WO2008033045A1 - Friction reducing surface and a mass and heat transfer enhancing surface - Google Patents

Abstract

The invention relates to aerohydrodynamics, power engineering, processive operations, increasing transport efficiency, medicine and to other fields of scientific-and-engineering activities and engineering practice. The inventive surface for reducing friction with gas or liquid media or with mixtures thereof is characterised in that a smooth surface, with or without a protective layer, is provided with cavities formed by concave and convex second-degree surfaces which are conjugated along a common tangent, wherein the cavities are conjugated with the initially smooth surface with the aid of convex surfaces which form slopes, for which the initially smooth surface is a tangent surface at interfaces thereof, wherein a concave surface forming the bottom part of the cavity is embodied in such a way that it is smooth or is provided with a dome, the relationship between the height hc of the cavity and the dimension L1 thereof in a stream direction, is situated within a range of 0.001≤ hc/L1 ≤0.1, the relationship of the dimension L2 of the cavity to the longitudinal dimension L1 thereof lies within the range of 0.25≤L2/L1≤1 at the frequency f of cavities distribution through the surface of 0.05≤f≤0.5. The inventive surface for enhancing mass and heat transfer is also provided with cavities of the above-specified shape, wherein 0.1≤ hc/L1 ≤0.5; 0.25≤L2/L1≤1; 0.1≤f≤0.8.

Description

 Surface to reduce friction and surface to intensify mass and heat transfer

Technical field

The invention relates to aerohydromechanics, energy, flow technologies, tasks of increasing transport efficiency, medicine and other areas of scientific and technical activity and engineering practice, in which the success of the development and implementation of flow processes and equipment, their functional and technical and economic characteristics depend on the quality flows of a continuous medium and the ability to control the processes of interaction between the flow and the surface as a whole and, in particular, the boundary layers of gas flows, their two-phase liquids and whether multicomponent mixtures in order to reduce aerohydrodynamic losses during the relative motion of the surface and the continuous medium, to reduce cavitation destruction of surfaces and to intensify exchange processes on them.

State of the art

Closest to the proposed surfaces is the technical solution according to the patent RU 2020304, September 30, 1994, containing flow surfaces that are the interface between a moving continuous medium (gases, liquids, their two-phase or multicomponent mixtures) and a solid energy-exchange wall, originally flat, cylindrical , conical or any other profile. The surface shape proposed in this patent, which is a three-dimensional either concave or convex relief, makes it possible to intensify the heat transfer between the boundary surface and the main flow with a non-accelerating level of intensification of the growth of aerohydrodynamic losses due to the formation of vortex structures on such reliefs. The ranges of sizes of the proposed reliefs are associated with the characteristics of the boundary layers of the flow, while, according to the proposed solution, the surface of the flow contains three-dimensional concave or convex relief elements distributed along it with rounded transition sections that pair these elements with an initially smooth surface; moreover, any the cross-section of relief elements parallel to the plane in which their three nearest peaks lie has the shape of a smooth closed line.

The disadvantage of this well-known patent is its unidirectionality, limited mainly by solving heat transfer problems and the lack of optimal solutions to increase critical heat loads in boiling processes, reduce cavitation wear on surfaces, reduce the rate of deposition of impurities from energy carrier flows on streamlined surfaces, and reduce aerohydrodynamic resistance and resistance between friction surfaces in friction pairs, etc., as well as the absence of correlations between the curvatures of the sections redlagaemoy surface having a different sign on the concave and convex parts of its terrain, it is necessary for their design and construction.

The technical result of the implementation of the surface to reduce friction and aero-hydrodynamic resistance of surfaces is: to reduce the aero-hydrodynamic resistance of energy-exchange channels containing the proposed curved sections that are streamlined by continuous flows;

- reduction of aerodynamic drag of bodies with streamlined surfaces of the same shapes moving in air, in water areas and on land, the speed of which is sufficient for self-organization of secondary tornado-like jets;

- reduction of friction between solid surfaces rubbing against each other in gaseous or liquid media or in their mixtures, for example, in friction pairs placed in these media, due to giving the rubbing surfaces curvilinear shapes, forming between them a vortex boundary layer from the environment, acting as vortex bearings.

The technical result of the implementation of the surface intensification of mass and heat transfer is:

- an increase in the rate of exchange of heat and mass between the flows of coolants and energy-exchange surfaces containing the invention of curved sections of double curvature, on which tornado-like jets are formed, accelerating exchange processes in gases, liquids and in their mixtures at a level of hydraulic losses that lags behind the intensification measure; increasing critical heat loads on energy-exchanging surfaces cooled by liquid coolants by imparting to these surfaces the proposed curvilinear shapes that change the kinetics of mass transfer in the process of phase transformation in a liquid medium;

- prevention of cavitation destruction of surfaces streamlined by fluid flows by giving them shapes containing curved sections, and creating conditions for the formation of secondary tornado-like jets on these surfaces, preventing the growth of vapor-gas formations (bubbles) and evacuating nuclei of such formations beyond streamlined surface limits;

- reduction of the adsorption of contaminants, impurities and the buildup of deposits from the moving medium on the energy exchange surfaces of the forms proposed above due to the removal of impurities from these surfaces into the main stream, for example, in the form of ash, or substances undergoing phase transformations, including products of incomplete combustion of fuel, salt deposits, other adsorbed substances, including ice and snow.

Disclosure of invention

отношение поперечного размера L₂ углубления к продольному размеру Li углубления находится в интервале:The technical result is achieved by the fact that the surface to reduce friction with gaseous, liquid media or their mixtures is characterized by the fact that on a smooth surface with or without a protective layer, double curvature depressions are formed formed by second-order convex and concave surfaces conjugated by a common tangent, with the conjugation of the recesses with the initially smooth surface is carried out using convex shapes of the surfaces forming slopes, for which the initially smooth the surface is tangent, and the concave surface forming the bottom of the recess is smooth or with a fairing, and the ratio of the depths h _{c of the} recesses to the dimensions Li of the recesses along the flow direction are in the range:

the ratio of the transverse dimension L _{2 of the} recess to the longitudinal size Li of the recess is in the range:

0.25 ≤ Lg / Li <1 (V) with a density f of the location of the recesses on the surface in the range:

0.05 ≤ f <0.5 (C)

The recesses can be made with longitudinal and / or transverse dimensions, varying along the stream.

The recesses can be applied either mechanically or electrochemically, or by forming on the surface a protective layer of polymer deposited on the surface followed by polymerization of the protective layer, or by surface treatment with a laser beam, or using combinations of these methods.

Slopes can be formed by a toroidal surface.

Slopes can be formed by a hyperbolic surface.

Slopes can be formed by an elliptical surface.

- r_sp)² + (h_c - h_sp)²]/2(h_c - h_sp). (E)A surface with a radius of curvature R (.) Having toroidal slopes, on which the radius of the recess r _{sp of the} concave spherical part is determined by the relation: r _sp = (2h _sp R ₍ . ₎ -H _sp ² ) ⁰ ' ⁵ (D) where h _sp - the depth of the concave spherical part of the recess; the radius of curvature of the convex part of the recess R ( ₊ ) is associated with its depth h _c and radius r _{c with the} ratio:

- r _sp ) ² + (h _c - h _sp ) ² ] / 2 (h _c - h _sp ). (E)

The surface is equipped with a fairing having the shape of a body of revolution with a curved base in the form of a part of the concave surface of the recess, while the projection of the fairing on any plane in which the axis of symmetry of these fairings and the tangent to the point of intersection of their axis of symmetry with the concave surface of the recess, is determined by the ratio: ri ² hi = const (F) where Гi is the radius of the fairing, hi is its height, taking values for the selected radius of curvature R (.) in the ranges l < G ⁵ ≤ hi ≤ l. (G)

The technical result is also achieved by the fact that the surface for intensifying convective mass and heat transfer with gaseous, liquid media or their mixtures is characterized in that depressions are formed on a smooth surface, formed by second-order conjugate convex and concave surfaces that are tangent to one another, and the depression is mated to the original a smooth surface is carried out with the help of convex surfaces forming slopes, for which, at the interface, the initially smooth surface is a kasate flax, and the concave surface forming the bottom of the recess is smooth or with a fairing, and the ratio of the depth h _{c of the} recess to the size Li of the recess along the flow direction is in the range:

0.05 <h _c / Li <0.5, (H) the ratio of the transverse dimension Lg of the recess to its longitudinal size Li is in the range:

0.25 ≤ L ₂ ALi <1, (I) with a density f of the location of the recesses on the surface in the range:

0, l ≤ f <0.8. (J)

The recesses can be made with longitudinal and / or transverse dimensions varying along the flow.

The recesses can be applied either mechanically or electrochemically, or by treating the surface with a laser beam or molding and polymerizing the surface of the protective layer, or using various combinations of these methods. Slopes can be formed by a toroidal surface.

Slopes can be formed by a hyperbolic surface.

Slopes can be formed by an elliptical surface.

- r_sp)² + (h_c - h_sp)²]/2(h_c - h_sp). (E)The surface of the recesses with a radius of curvature R (.> Having toroidal slopes and a spherical concave part, the radius r _{sp of} which is determined by the relation: r _sp = (2h _sp R ₍ . ₎ - h _sp ² ) ⁰ ' ⁵ (D) where h _sp - the depth of the concave spherical part of the recess; while the radius of curvature R ₍₊ ) of the convex part of the recess is associated with its depth h _c and radius r _{c with the} ratio:

- r _sp ) ² + (h _c - h _sp ) ² ] / 2 (h _c - h _sp ). (E)

The surface can be equipped with a fairing having the shape of a body of revolution with a curved base in the form of a part of the concave surface of the recess, while the projection of the fairing on any plane in which the axis of symmetry of these fairings lie and tangent to the point of intersection of their axis of symmetry with the concave surface of the recess is determined by the ratio :

Гi ² hj = сopst where r, is the radius of the fairing, hi is its height, taking values in the ranges l <Г ⁵ ≤ hi / ri <l for the selected radius of curvature R (.). (G)

On the surface of the heat exchanger plate, the recesses can be staggered or corridor-like, and the size of the recesses and their depth can increase or decrease in the direction of flow along the plate.

Around the main recesses can be located recesses with smaller longitudinal, transverse dimensions and depths.

On the other side of the surface are protrusions corresponding to the recesses.

On the other side of the plate surface are ribs oriented along the plate in the direction of flow. The recesses may be located on the other side of the plate symmetrically or asymmetrically with respect to the recesses of the main side of the plate.

The additional surface of the plate containing the recesses is placed relative to the main surface with the formation of a heat exchange channel, while the surfaces of the main and additional plates with recesses are facing each other and are located in parallel due to the spacing elements in the form of protrusions of a spherical, conical, cylindrical or other shape.

The surface of the pipe, in which the recesses along the pipe and across the pipe are staggered or corridor.

The size of the recesses and their depth increase or decrease in the direction of flow along or across the pipe.

On the inner surface of the pipe are protrusions having second-order surfaces.

Recesses may be located on the outer surface of the pipe, and protrusions may be located on its inner surface.

On the inner surface of the pipe can be located longitudinal ribs with recesses.

On the inner surface of the pipe can be located transverse ribs with recesses.

A curved twisted tape with recesses may be located inside the pipe.

On the inner surface of the pipe can be symmetrically or asymmetrically located recesses relative to the recesses on the outer surface.

The longitudinal, transverse dimensions and depth of the recesses deposited on the inner surface of the pipe increase or decrease in the direction of flow,

Recesses are located on the inner surface of the pipe and a curved twisted tape with recesses is installed inside the pipe. The inner surface of the pipe is made without a recess and a twisted tape with recesses is installed inside the pipe.

Brief Description of the Drawings

In FIG. 1 shows a fragment of a flow surface containing one recess, the totality of such recesses forms a flow surface and implements the proposed method.

In FIG. 2 shows the surface of the recess with a cowl in the form of a double recess deposited on the surface according to the method one in the other.

In FIG. 3 shows the surface of the recess with fairings in the form of many small recesses on its surface.

In FIG. 4 - the surface of the recess with a fairing in the form of a recess.

In FIG. 5 is a diagram of the streamlines of a medium involved in the formation of a secondary swirling structure in a recess on the surface at low speeds of relative motion of the surface and the medium.

In FIG. 6 shows the same process visualized by photographing.

In FIG. 7 shows a visualization of the process of compressing a vortex into a recess and absorption into a vortex of a medium from a wall layer of a stream flowing around a surface with recesses.

In FIG. 8 shows a visualization of a turbulent flow around a relief of three-dimensional depressions.

In FIG. 9 shows the result of measuring the thickness of the boundary layer on the surface with a recess. 1 - smooth surface, 2 - surface with a recess; the maximum on curve 2 corresponds to the coordinates of the zone of expiration of the tornado-like jet from the recess.

In FIG. 10 shows a three-dimensional pressure plot experimentally measured on the surface of a recess. The reduced pressure at the periphery corresponds to the absorption of the medium from the boundary layer into the recess, and the increased pressure zone (dome) in the central part of the recess determines the pressure at the end of the self-organizing tornado-like jet, which ensures the outflow the main flow of the mass of the medium; sucked in by a whirlwind; the zone of location of the maximum pressure in the recess coincides with the zone of location of the maximum thickness of the boundary layer above the recess in FIG. 9 and with the coordinates of the location of the fairing from the surface Gertler vortices in FIG. 11, which indicates the "extrusion" of a tornado-like jet from the recess.

In FIG. Figure 11 presents a visualization of the main stream flow around the recess, demonstrating a change in the structure of the boundary layer due to the formation of surface Hertler’s vortices in the form of “brackets”, indicated by arrows, which replace shear stresses in the traditional Prandtlé layer of adhesion by rolling stresses “brackets” on the surface, which is necessary the condition for self-organization of tornado-like vortices and the basis for reducing friction stresses on the proposed surfaces. In the photograph, a fairing is constructed, built of Gertler’s vortices by a secondary swirling current in a depression of the selected shape. The trunk of a tornado-like vortex, as follows from the examination of the photograph, is filled with “braids” - Gertler’s vortices, sucked off by the tornado-like vortex, which in the case of using such surfaces for heat and mass transfer causes its high intensity.

In FIG. 12 shows the surface of a heat exchanger plate with longitudinal ribs.

In FIG. 13 shows the placement of the plates to form a heat exchange channel.

In FIG. 14 shows the surface of a heat exchanger pipe.

In FIG. 15 shows the surface of a pipe with longitudinal ribs.

In FIG. 16 shows the surface of the pipe with transverse ribs inside.

Embodiments of the invention

The flow surfaces to reduce friction stresses (TLJS-DR) and intensify mass and heat transfer (TLJS-HMT), proposed in the invention, provide the necessary and sufficient conditions for the formation of a new class flows covering the possibilities of increasing the functional and technical and economic efficiency of practically the entire fleet of flow processes, apparatuses, equipment and transport units used in human scientific and practical activities.

Surfaces TLJS-DR (Torpedo Liket Jet Surfase-Result) are used for:

- reduction of aerohydrodynamic resistance of various bodies in relative motion with a continuous medium, including airplanes, cars, trains, river, sea and ocean vessels and yachts;

- reduce pressure losses in the pressure channels transporting gases, liquids and their mixtures.

TLJS-HMT surfaces (Tomato Liket Jet Surf-Net & Mass Trapfinder) are used for:

- increase the functional efficiency of energy-exchange flow processes and equipment, including units for heat and mass transfer; reduction of cavitation wear on the surfaces of hydraulic turbomachines, propellers of ship propellers, hydraulic pumps and other units exposed to cavitation processes;

- heating and cooling magnetothermal units to convert low-grade heat fluxes into mechanical and electrical forms of energy;

- increase the functional efficiency of other energy-exchange flow processes and equipment.

The above areas of use of the invention determine a variety of options for its implementation. However, common to all possible options when setting a specific task are:

- quantitative determination of the basic functional characteristics of processes or equipment that are expected to be improved;

- selection of shapes and sizes of reliefs based on an analysis of task parameters;

- The choice of technology for applying reliefs on the surface. As an example, we give a relief streamlined by a stream of a continuous medium, the convex part of which is a segment of a torus having a section in the form of a circle, and the concave part is a segment of any second-order surface, for example, spherical. The convex part of the curved surface of the recesses - slopes, external to the geometric center of the recesses, is characterized by the radius of curvature R ( ₊ ), and the other, or the internal part of this surface, for example, a segment of a sphere located around the geometric center of the curved section, is characterized by the radius of curvature R _Q and the curvature and shape of the convex toroidal part is determined by the ratio:

R ₍₊ ) = Kgs - r _sp ) ² + (h _c - h _sp ) ² ] / 2 (h _c - h _sp ). (E) and the shape of the concave part, by the ratio:

R (-) = (r _Sp ² + h _sp ² ) / 2h _sp , (D) the ratio of the radii of curvature of the convex and concave parts of the recess is found from the corresponding ratio of conditions (Q) (see below) in the interval:

10- ⁶ _{<R (+ / R ()} <l; when the conditions that determine the stability limit of the boundary layer flow on the surface with respect to the emergence surface Goertler vortices.:

[δ ₂ (x) / R ₍ .)] ⁰ ' ⁵ ILo δ ₂ (x) / v>7; [δ2 (x) / R ₍₊₎ l ⁰ ' ⁵ U _m δ ₂ (x) / v> 7, (К) where U∞ is the velocity of the flow flowing onto a curved surface with radii of curvature R ( ₊ > and R ( .), δg (x) is the thickness of the pulse loss in the boundary layer formed by the flow of the medium on the streamlined surface, v is the viscosity of the flowing medium; it is taken into account that the critical velocities U∞ for the isothermal flow are lower for concave sections of the recesses compared to the critical value speeds for convex sections.

A curvilinear relief is applied to the streamlined surface (Fig. 1) in the form of separate recesses 1 of double curvature, each of which consists of the concave part 2 of the inner curved surface of the recess, having the selected curved shape in the form of a second-order surface without acute angles on it, including, for example, a spherical shape with a radius of curvature R (.), or an elliptical shape with radii of curvature R _nn (-) and Rmaχ (-), mating with an initially smooth surface 3 convex curved slopes of a toroidal shape of a round, elliptical, parabolic or hyperbolic sections with radii of curvature for which, at the junctions, the initially smooth surface is tangent, and concave and convex surfaces have common tangents at the conjugation points. Values of Rшш (.). Rmaχ (-) _> Rmin (+) and Rmax (+) are determined similarly to the above from the relations (Q):

10- ⁶ _{<R (+) / R {} -) <l; 10- ^b <R _{max (+} / R ₍ . ₎ <L; lО ^ & ^ - fВ + ≠ ϊ,

10 ≤Rmax (+) / Rmax (-) ≤l; 10 <Rmin (+) / Rinax (-) ≤l;

A surface for reducing friction with a gaseous, liquid medium, or mixtures thereof, is characterized in that, on a smooth surface with a protective layer in the form of a polymer material deposited on this surface or without it, recesses 1 are formed formed by the convex 4 and concave 2 surfaces of the second of order, the conjugation of the recesses with the initially smooth surface 3 is carried out using forming ramps, convex surfaces, for which in the places of conjugation the initially smooth surface is are tangent, moreover, the concave surface forming the bottom of the recess is smooth or with a cowl 5, and the ratio of the depth h _{c of the} recess to the size L _{1 of the} recess along the flow direction is in the range

при плотности f расположения углублений на поверхности, находящейся в интервале:0.001 ≤ h / Li ≤ OD (H) the ratio of the transverse dimension L _{2 of the} recess to the longitudinal Li size of the recess is in the range:

when the density f of the location of the recesses on the surface located in the interval:

0D <f <0.5. (FROM) The recesses on the surface can be made with longitudinal and transverse dimensions, varying along the stream.

The recesses can be applied either mechanically or electrochemically, or by molding and polymerizing the protective layer, or by surface treatment with a laser beam, or using combinations of these methods.

Slopes can be formed either toroidal, or hyperbolic, or parabolic, or elliptical surfaces.

With the toroidal shape of the slopes with a cross section in the form of a circle, the deepening radius r _{sp of the} concave spherical part of the curved surface having a radius of curvature R ₍ .) Is determined by the relation: r _sp = (2h _sp R ₍ .) - h _sp ² ) ⁰ ' ⁵ ( D) where h _sp is the depth of the concave spherical part of the recess; the radius of curvature of the convex part of the recess R ( ₊ ) is associated with its depth h _c and radius r _{c with the} ratio:

R ₍₊ ) = [O _c - r _sp ) ² + (h _c - h _sp ) ² ] / 2 (h _c - Ji ₄ ,). (E)

Fairings on such surfaces are in the form of bodies of revolution, the curvilinear base of which are parts of the concave surface of the recess, and the projection of the fairing on any plane in which the symmetry axis of the fairing lies and tangent to the intersection of this axis with the concave surface of the recess is determined by the ratio:

Гi ² hi = sopst, (F) where ri is the radius of the fairing, hi is its height, which, for a selected radius of curvature R (.), Takes values in the ranges:

10 ^"5 <hi / ri <1 (G)

Fairings can be made in the form of recesses, double recesses or recesses located on the surface of the main recess (figure 2 - figure 4).

The surface for intensifying convective mass and heat transfer with a gaseous, liquid medium or mixtures thereof is characterized in that depressions 1 are formed on a smooth surface and are formed by tangent convex 4 and concave 2 second-order surfaces, wherein the recess is conjugated to an initially smooth surface 3 by means of convex surfaces forming slopes for which the initially smooth surface is tangent at the interface, the concave surface forming the bottom of the recess is smooth or with a cowl 5, and the ratio of the depth h _{c of the} recess to the size L _{1 of the} recess along the flow direction is in the range:

0.1 <h _c / Li <0.5, (H) the ratio of the transverse dimension to the longitudinal dimension of the recess is in the range:

0.25 <IVL ₁ <1, (I) with a density f of the location of the recesses on the surface in the range:

0, l ≤ f <0.8. (J)

The recesses can be made with longitudinal and / or transverse dimensions varying along the flow.

The recesses were applied either by mechanical or electrochemical methods, or by forming and polymerizing a protective layer, or by treating the surface with a laser beam, or using combinations of these methods.

Slopes can be formed either toroidal, or hyperbolic, or parabolic, or elliptical surfaces.

The radius of the recess r _{sp of the} concave spherical part of the curved surface has a radius of curvature R (.) And is determined by the relation: r _sp = (2h _sp R _(-) - h _sp ² ) ⁰ ' ⁵ , (D) where h _sp is the depth of the concave spherical part recesses; the radius of curvature of the convex part of the indentation R ₍₊ ) of its slopes is related to the depth h _c and its radius r _{c with the} ratio:

R ( ₊₎ = [(Gc - r _sp ) ² + (h _c - h _sp ) ² ] / 2 (h _c - h _sp ). (E)

Fairings 5 may be in the form of bodies of revolution having a curved base in the form of a part of the concave surface of the recess, while the projection onto any plane in which the axis of symmetry of these fairings lie and tangent to the point of intersection of the axis of their symmetry with the concave surface of the recess is determined by the ratio:

T ₁ ² hi = const (F) where Г} is the radius of the fairing, hj is its height, which, for a selected radius of curvature R (.), Takes values in the ranges:

10G ^s ≤ Wr ≤ l. (G)

On the surface of the heat exchange plate 6, the recesses 1 can be staggered or corridor-like.

The size of the recesses and their depth may increase or decrease in the direction of flow along the plate.

Around recesses of a larger size, recesses with smaller dimensions and depths can be symmetrically located. On the other side of the plate 6, protrusions corresponding to the recesses may be located. On the other side of the plate can be located ribs 7, oriented along the plate in the direction of flow.

The recesses on the other side of the plate can be located symmetrically or asymmetrically with respect to the recesses of the main side. The additional surface of the plate 12 can be placed relative to the main surface of the plate 6 with the formation of a heat exchange channel, while the surfaces of the main and additional plates with recesses face each other and are located in parallel due to the spacing elements 8 in the form of protrusions of a spherical, conical, cylindrical or other shape.

On the surface of the pipe 9, the recesses can be located along and across the pipe in a checkerboard or corridor order.

The size of the recesses and their depth can increase or decrease in the direction of the flow or across it.

On the inner surface of the pipe 9 can be located spherical protrusions (not shown), longitudinal ribs 10, or transverse ribs 11, or twisted tape 13 with recesses. The recesses on the inner surface of the pipe can be located symmetrically or asymmetrically with respect to the recesses on the outer surface.

On the inner surface of the pipe can be located recesses, the size and depth of which increase or decrease in the direction of flow along the pipe.

Recesses may be located on the inner surface of the pipe and a curved twisted strip with recesses is installed inside the pipe.

The radii of curvature of the relief, the radii of the traces of the recesses on the formed surface, the depth of the relief and the parameters of the fairing in the case of its arrangement in the recesses are determined by the above ratios and ranges named by the letters, (A) ₅ (B) ₅ (C) ₅ (D) ₅ (E ) _J (F) ₉ (H) ₉ (I) ₅ (J) (K) and (Q). For example, choose a channel or body, the functioning of which is associated with the relative motion of their surface and continuous medium. The main aero-hydrodynamic characteristics of the flows of gases, liquids or their two-phase mixtures are determined in the case of the formation of the proposed flow with built-in tornado-like jets in the channels or similar characteristics for a body moving in the above environments. The ranges of possible changes in the thermophysical properties of the working medium are established, the characteristic size that determines the mode of relative motion of the continuous medium and surface, the Reynolds numbers (Re) are calculated and the possible ranges of their changes are determined. In accordance with the result of the analysis, the Re numbers are varied in order to select the possible radii (sizes) of the trace of the recesses on the moldable surface, trying to place their integral numbers along and across the flow or in the direction of movement of the body. In accordance with the problem solved by forming a flow with built-in tornado-like jets, the shape of the recesses, the radii of their curvature, and the relief density f are selected using the ranges of their changes indicated by the letters (A), (B), (C) (E) and (Q). Given that the value f = πr _c ² / tit ₂ , ti and tg are selected — the transverse and longitudinal steps of the location of the recesses on the initially smooth surface, respectively, so that, when best approximated to a given value f, the number of recesses along and across the moldable surface would be integral. Following the selection of f, ti and t ₂ , the radius of the trace of the recess on the surface is determined from the relation: r _c = (H ₁ I ₂ At) ⁰ ' ⁵ .

Using the range of values h _c / r _c indicated by the letters (A) or (H), depending on the problem being solved, the depth h _{c of the} constructed relief is calculated. In accordance with the chosen radii of curvature, the density of the recesses, the size of the traces and depths of the relief, they develop a technology for forming the surface, prepare the appropriate tool and make channels or bearing surfaces.

The present invention is based on the phenomenon of self-organization of quasipotential tornado-like jets of gases, liquids and / or their two-phase mixtures in recesses having a second-order boundary surface discovered by the authors, about 30 years ago, and rearrangement on such surfaces of the boundary layer when these media flow around surfaces with recesses . This phenomenon has been experimentally studied, theoretically described, visualized and tested in laboratory and field conditions in a wide range of velocities and pressures, including in the ranges of subsonic and supersonic air flow velocities and at critical and supercritical parameters of liquid coolants.

The velocity and pressure fields in the tornado-like jets detected are described by exact solutions of the basic non-stationary equations of viscous fluid hydrodynamics (Navier-Stokes and continuity equations), and the knowledge and experience gained in the research and development of molded surfaces provided the necessary and sufficient conditions for their formation, which is the subject of the invention.

The detected jets and the process of their self-organization were named by us Torpedo Like Jet (TLJ) and Torpedo Like Jet SeIf Orgapizatiop Rocess (TLJSOP), respectively; the surface on which the TLJSOP emerges is called TLJ-Surface (TLJS), and the technologies using such jets are called TopJet Jet Technologies (TLJT).

Numerous aerohydrodynamic and technical experiments, the development and testing of experimental and field models of flow equipment and transport units with high reliability indicate a decrease with the help of TLJT friction stresses on streamlined surfaces (see Fig. 8-10) and the intensification of heat and mass transfer when lagging behind the measure of its increase hydraulic losses. In this case, TLJs are formed in flows of gases, liquids, and in their mixtures at practically important regimes of continuous medium motion corresponding to Reynolds numbers Re> 5-10, calculated from the geometric dimensions of the selected curvilinear relief, for example, by the diameter of symmetrical recesses d _c or by their depth h _c defining the characteristics of the secondary flow in the recess.

The visualization of the process of formation of TLJ flows given in the photographs of FIG. 5, 6, 7, and 8 allows one to see a radially converging tornado jet elongated from the cavity and built into the flowing stream, the longitudinal size of which substantially exceeds the transverse one, and its spatial orientation in the stream indicates the connection of one end of the jet with the curved surface of the cavity, from which the jet sucks the mass of the continuous medium also expires, and to the connection of its second end face or with the curved surface of a neighboring depression located downstream into which a tornado-like jet blows glubleniya weight of the continuous medium or from host this mass corresponding zone of the main flow, wherein the pressure and velocity swirling jet stitched with the pressure and flow rate.

It has been experimentally proved that tornado-like jets (TLJs) self-organize on TLJS in the recesses of the special relief described below with the relative motion of the molded boundary surface and a viscous continuous medium. In this case, the flow of the medium or the motion of bodies in the medium is characterized by Reynolds numbers calculated by the size of the recesses along the flow or in the direction of the body-Re> 500, moreover, the selected shapes and sizes of curvature of the convex and concave parts of the relief initiate the action of forces absent when flow around smooth surfaces and rearrangement of the boundary layer of the flow from shear on its initially smooth sections to a three-dimensional curved boundary layer consisting of surface vortices such as Gertler’s vortices or their ensembles linear surface.

The dimensionless relation (K), composed of the radius vector of the surface curvature R ₍₊₎ or R ₍ .) (Hereinafter, the radius everywhere), the viscosity of the medium v, the magnitude of the velocity vector of the unperturbed continuous flow U∞, and the pulse loss thickness δ ₂ (x) in the boundary layer of the flow, being a stability criterion with respect to the appearance of surface vortices such as Gertler vortices in the boundary layer, indicates the possibility of controlling the vortex boundary layer using the parameters of the flow of a continuous medium and the radius of curvature of the streamlined surface. In a boundary layer of this type, which we called a finely dispersed moving boundary layer [Fépélou Dispersible Mobil Vohidaru Lauer (FDMBL)], the nature of the friction stresses on curved surfaces changes, turning from shear to friction-driven rolling. This quality is one of the main advantages of the proposed TLJS, a prerequisite for self-organization of the TLJ, and one of the main reasons for the reduction of friction stresses when flowing around curved-linear concave reliefs. The presence of a three-dimensional vortex boundary layer (FDMBL) provides the conditions for the conjugation of TLJ with the concave surface of the recesses and does not lead to energy dissipation in a rotating flow, which destroys, as is known, vortex systems formed on smooth surfaces, where the “sticking” conditions L. Prandtl, requiring equalizing the flow rate with the speed of the streamlined surface, and there is no FDMBL. In the case of a three-dimensional vortex layer, this condition is fulfilled indirectly through the surface vortices arising at the ends of the formed tornado-like jet, which “settled” these surface structures (see Fig. 11). FDMBL surface vortices moving along a curvilinear relief similarly to a roller or wheel have, at the points of contact with the surface or on the interface line with it, the speed, as indicated above, equal to the surface velocity, in the case of resting channels or plates at TLJS, equal to zero, and in case of TLJS moving with a given speed U∞ - equal to this speed, which corresponds to the conditions of "adhesion". The remaining surface points of these vortices move with non-zero velocities corresponding to the velocities of the vortices generating these vortices and stitched with them like a swirling stream (see photo of Fig. 11). In the case of TLJ, the ensemble of vortices forming FDMBL is formed by the swirling flow itself at the ends of the jet on a curved surface and is used by a tornado vortex, figuratively speaking, for rolling on these vortices along the surface of the recess. This explains the mechanism for reducing energy dissipation in self-organizing tornado-like jets. In addition to this process, the boundary layer on a curved surface is structured into large formations, consisting of vortices in the form of microscopic “brackets” visualized in the photograph of FIG. 11. Self-organizing vortex jets, as mentioned above, suck off the boundary layer, consisting of such “brackets”, from the surface of the recess and from the smooth part of the relief surrounding it, transferring the suction mass to the main stream. Each of these “kitties” significantly exceeds the mass and volume of turbulent moths, which determine the efficiency of heat and mass transfer mechanisms in turbulent flows, which explains the advantages of TLJS compared to other forms of relief traditionally used to intensify heat and mass transfer.

The three-dimensional relief of the recesses and the TLJ self-organizing in it transform the streamlined molded surface:

- into the system of runoffs of a working continuous medium from the boundary layer of the current into the recesses, moreover, the flow is provided by the acceleration of the flow on convex slopes of the relief, causing a decrease in static pressure in this zone of the formation of the jet, and the flow rate is determined by the chosen shape and curvature of the boundary surface; - to the system of sources of tornado-like jets, flowing and sucking from the recesses, surface vortices and vorticity from FDMBL formed on the sections of a curved surface, transferring to the main stream, as indicated above, the masses of a continuous medium flowing into the recesses in the form of large formations - macroscopic “little ones” rendered in the photograph of FIG. eleven.

The mechanisms of these processes, as indicated above, reduce friction stresses on molded surfaces, intensifying heat and mass transfer processes on them; Moreover, the laws of these processes on surfaces with convex-concave reliefs differ significantly from those describing the processes of friction and exchange when flowing over relatively smooth and rough surfaces that “generate” turbulence in the wall layers of the flow, for example, due to natural or artificial roughness.

Tornado jets are formed, as described above, in the recesses at the “surface - moving medium” interface under the action of forces caused by the shapes of the selected relief, including:

- braking forces arising under the influence of dynamic pressure of the flow on the downstream slopes of the recesses, causing, to the extent of the squared magnitude of the velocity of the flowing stream Ui _n ^{2, the} elastic reflection of the flow from the concave slopes and the appearance in the concave part of the recesses of the return flow moving in the bottom region of the recess with speed, not much different from Uj _n . (U is the velocity of the flow flowing into the recess, measured at the interface between the recess and the initially smooth surface at a point at a height of 0.1 mm above it and in the return flow inside the recess at a point lying on the central meridian on the downstream slopes). On slopes meeting the main stream flowing into the recesses, it is cross-linked with the return flow, generating a vortex structure inside the recesses with medium circulation Г0 = 2πRUφ, while the azimuthal velocity of such circulation is U ₄ , = Uj _n = kUос, where k <l reflects Peculiarities of the profile of the flow velocity over the initially streamlined throat and curved surfaces. Due to the small difference in velocities in the inflowing stream and in the return flow generated by it in the recess (in the experimental data, the difference "k" in the return and flowing flows is no more than ~ 8%) a pair of forces acts on the vortex structure formed in the recess, self-similarly rotating the vortex in the recess by an angle β ~ 45 ° relative to the direction of the main flow and causing an additional twist of the jet;

- mass inertial forces directed along the radii of curvature of the recesses to their center and forming a two-dimensional velocity field on the convex slopes of the relief in a moving medium, containing the radial U _r and azimuthal U _φ with respect to the central axis of the recess, velocity components. Moreover, the movement of the medium along curved convex slopes leads to a decrease in the probability of flow separation and, as mentioned above, to the formation of a three-dimensional vortex boundary layer FDMBL on them. The characteristics of the surface vortices arising in such a layer on a curved surface depend, as is known, on the velocity Ui _n , the state of the boundary layer (laminar, turbulent), the thickness of the momentum loss Lr in it, and the radii of curvature of the convex-concave relief R ( ₊ ) and R (.), respectively. Such a boundary layer, as indicated above, reduces the level of energy dissipation in the flow, reducing the likelihood of its separation from the convex surface of the slopes, and gives the current in the recess a high dynamism due to the conversion of the shear boundary layer into a three-dimensional vortex with which the formed swirl flow is crosslinked. Further formation of tornado-like jets occurs on concave slopes of the recesses also under the influence of mass inertia forces directed in this zone from the surface into the main stream along the radii of curvature to its center. The choice of the geometric shape of the convex-concave sections of the boundary surface and the corresponding radii of curvature of the relief of the recesses determines the effect on the formed swirling jet of inertia forces, which impart a longitudinal velocity component U _{z to} this secondary flow. This component arises due to the action on the stream flowing into the recesses with a speed U = (U _φ ² + U _r ² ) ^{0 5} , accelerations a = U ² / R, directed along the radii of curvature R from the concave surface into the stream and imparting to the jet additional radial convergence, increasing as its radius r decreases, the azimuthal velocity of the secondary flow Uφ, and the longitudinal pressure gradient determined by it and the longitudinal velocity U ₂ . A similar mechanism provides the TLJ pressure plot necessary for transferring and blowing mass of a medium sucked off by tornado-like jets onto a surface lying downstream or into the main flow;

- forces such as the Magnus force arising due to the interaction of the main flow flowing into the recesses with a tornado-like vortex, the circulation of Go in the cavity generates a lifting force F, which depends on the velocity of the flowing current Uj _n , and the effective size of the vortex structure across the flow L;

F = pU _m ГОL directed from the concave part of the curved surface into the flow normal to the plane in which the velocity vector of the main flow and the vector determined by the direction of circulation in the vortex structures are located, where Ui _n and Го are defined above, and the p-density of the continuous medium in a whirlwind.

These forces, together with the mass forces of inertia acting on the concave part of the relief, provide a “tack” of tornado-like vortices in the flowing stream, pull one of the ends of the vortex and its “path” into the main stream.

The magnitudes of the forces listed above and the directions of their action on the structure of the formed flow are controlled, as indicated above, by the specified shapes of the double-curvature depressions, their density with respect to the area of the initially smooth surface, and the flow regimes of the flowing medium. For example, in the process of flowing around recesses, the shape of which has central axial symmetry and is determined by the radii of curvature R ₍₊ ) and R ₍ .) Per continuous flow, characterized by Reynolds numbers Re≥500, calculated from the diameter d _c = 2r _c , of the trace of the recess by of the formed surface and moving over the convex slopes of the recesses with a speed Ui _n , mass inertia forces act, compressing, in accordance with the sign of curvature R ₍₊₎ , the flow to the convex slopes. These forces reduce the probability of separation of the flow from the curved surface of the recess and inform the flowing into it of a flow greater or less, depending on the chosen radii of curvature, radial convergence and azimuthal velocity U _φ . Such a movement, as indicated above, forms between the curved surface and the tornado-like flow of FDMBL, and such a boundary layer accompanies the formed flow on the concave part of the recess. Surface vortices such as Gertler’s vortices give the swirling jet in the recess dynamism with respect to a curved surface, stabilize its outflow into the main flow, constructing a fairing from these vortices, formed by the structure of the swirling tornado-like flow and the curved shape of the recess (see photo of Fig. 11).

In accordance with the stated reasons, the interface “continuous medium - streamlined surface * is given a curvilinear shape in the form of regularly alternating depressions of double curvature, creating a force action that ensures self-organization in the flow in these FDMBL zones and secondary swirling jets directed from the indicated surface zone of the flow into mainstream. In this case, the forces that arise cause an independent force impact on the moving medium, which leads to a curvature of the forms of the flow stream lines, and, as a result, to self-organization of tornado-like jets.

The relief of depressions applied to streamlined surfaces, as established in theoretical and experimental studies, changes the structure of the boundary layer of the flow on the boundary surfaces, generates self-organization of tornado-like jets, sucking off a part of the continuous medium concentrated in the zone where the recesses are located on the streamlined surface, affecting the level of flow energy dissipation , and intensifying the exchange processes between the swirling jet and the surface. The choice of the radii of curvature and the size of the curved sections of the streamlined surface is carried out on the basis of theoretical calculations confirmed in experimental studies, they provide the technology of their deposition on the surface and the self-organization conditions of the secondary tornado-like jets built into the flowing stream are fulfilled. The flow of a working continuous medium is either directed onto surfaces formed by recesses, or a relief of this form is applied to the surface of bodies moving in a medium of gases, liquids, or in their two-phase mixtures, reaching this reduces friction stresses on molded surfaces and intensifies the processes of mass and heat transfer between the energy exchange surface and the flows of a continuous medium.

Industrial applicability

The proposed surfaces are used to reduce the aerohydrodynamic resistance of pressure channels and various bodies in a state of relative motion with a continuous medium, and / or to increase the functional efficiency of energy transfer processes and equipment, including heat transfer and mass transfer processes, as well as in other areas, everywhere where, in comparison with traditional methods of mass and heat transfer, it is necessary to intensify metabolic processes with a limited increase or decrease in hydraulic resistance phenomena and reduce cavitation wear of the surfaces of hydraulic turbines, hydraulic pumps, propellers of ship propulsors and other devices operating in a liquid medium. In particular, the invention finds application in various modes of transport, including aircraft, automobiles, high-speed rail trains, sea and river vessels, gas turbine units with cooled blades, nuclear power uranium assemblies, steam generators, various heat exchangers, recuperators and other energy exchangers and devices, in household appliances, including in air conditioners, fans, heating appliances, in kitchen utensils such as kettles, pots, pans and R., in various types of sports equipment, including sports cars, motorcycles, bicycles, tracksuits for motorcycling, cycling, swimming, running, etc., in various biochemical processes associated with the movement of gaseous or liquid reagents, as well as the creation of devices and prostheses for circulatory systems, in medical devices for artificial blood supply, purification of blood from harmful impurities, in artificial respiration devices, etc., in other words, in all types of flow technologies in which technological efficiency is due to the movement of gases, liquids, their two-phase and / or multicomponent mixtures.

The above areas of use of the invention determine a variety of options for its implementation. However, common to all possible options when setting a specific task are: determination of the main functional characteristics of processes or equipment that are supposed to be improved, and, based on an analysis of parameters, the choice of shapes, sizes and technology of applying reliefs on the surface.

Claims

Claim 1. A surface for reducing friction with gaseous, liquid media, or mixtures thereof, characterized in that depressions are formed on a smooth surface with or without a protective layer, formed by second-order convex and concave surfaces conjugated by a common tangent, while the depression is mated to an initially smooth surface is carried out with the help of convex surfaces forming slopes, for which, at the interface, the initially smooth surface is tangent, and the concave surface forming d nnuyu recess portion, is made smooth or with a fairing, and the ratio of depth h _c recess to recess the size L ₁ along the flow direction are in the interval _(with HOOl≤h / Li≤OD, the transverse dimension ratio of L ₂ to recess the longitudinal dimension L ₁ is recess in the range

with a density f of the location of the recesses on the surface located in the range of 0.05 <f <0.5. 2. The surface according to claim 1, on which the recesses are made with longitudinal and / or transverse dimensions varying along the stream. 3. The surface according to claim 1, on which the recesses are deposited either mechanically or electrochemically, or by molding and polymerizing the protective layer, or by treating the surface with a laser beam. 4. The surface according to claim 1, on which the slopes are formed by a toroidal surface. 5. The surface according to claim 1, on which the slopes are formed by a hyperbolic surface. 6. The surface according to claim 1, on which the slopes are formed by an elliptical surface. 7. The surface according to claim 4, on which the radius of the recess r _{sp of the} concave spherical part of the curved surface having a radius of curvature R ₍ ^ is determined by the relation: r _sp = (2h _sp R _(-r h _sp ² ) ⁰ ' ⁵ , where h _sp is the depth of the concave spherical part of the recess; the radius of curvature of the convex part of the recess is associated with its depth h _c and radius r, the ratio: R ( ₊₎ = [(r _c -rsp) ² + (h _c -h _sp ) ² ] / 2 (h _c -h _sp ). 8. The surface according to claim 1, on which the fairing is in the form of bodies of revolution with a curved base of which is part of the concave surface of the recess, and the projection of the fairing on any plane in which the symmetry axis of the fairing lies and tangent to the intersection of this axis with the concave surface of the recess is determined by the ratio : Гj ² hi = cpst where Гi is the radius of the fairing, hi is its height, taking values in the ranges for the selected radius of curvature R (.)

P 9. The surface for intensifying convective mass and heat transfer with gaseous, liquid media or their mixtures is characterized in that depressions are formed on a smooth surface, formed by second-order convex and concave surfaces conjugated by common tangent, while the depression is conjugated with an initially smooth surface using convex surfaces' forming slopes, for which, at the interface, the initially smooth surface is tangent, and the concave surface forming I bottom of the recess is made smooth or with a fairing, and the ratio of depth h _c recess to recess the size L ₁ along the flow direction is in the range _from OjOS≤h / Li≤OD transverse dimension ratio L ₂ recesses to the longitudinal dimension L ₁ is in recess interval

when the density f of the location of the recesses on the surface is in the range of 0.1 <f ≤ 0.8. 10. The surface according to claim 9, on which the recesses are made with longitudinal and / or transverse dimensions varying along the flow. 11. The surface according to claim 9, on which the recesses are applied either mechanically or electrochemically, or by treating the surface with a laser beam, or by molding and polymerizing the surface of the protective layer, or by using various combinations of these methods. 12. The surface according to claim 9, on which the slopes are formed by a toroidal surface. 13. The surface of claim 9, wherein the slopes are formed by a hyperbolic surface. 14. The surface of claim 9, wherein the slopes are formed by an elliptical surface. 15. The surface according to claim 12, on which the radius of the recess r _{sp of the} concave spherical part of the curved surface having a radius of curvature R ₍ . _{) Is} determined by the relation: r _S p = (2h _sp R _(-) -h _sp ² ) ⁰ ' ⁵ , where h _sp is the depth of the concave spherical part of the recess; the radius of curvature R ( ₊ ) of the convex part of the recess is associated with its depth h _c and radius r _{c with the} ratio: R ₍₊₎ = [(r _c -r _sp ) ² + (h _c -h _sp ) ² ] / 2 (h _c -h _sp ). 16. The surface according to claim 9, in which the fairings are in the form of bodies of revolution having a curved base in the form of a part of the concave surface of the recess and projected onto any plane in which the axis of symmetry of these fairings and tangent to the point of intersection of the axis of symmetry with the concave surface of the recess lie and the shape of this projection is determined by the relation: r; ² hi = cpst where Гj is the radius of the fairing, hi is its height, taking values in the ranges at the chosen radius of curvature R ₍ . ₎ Yu ^"5 <! H.≤ l. Rι 17. The surface of the heat transfer plate according to claim 9, in which the recesses are staggered or corridor-like. 18. The surface of claim 17, wherein the size of the recesses and the depth increase or decrease in the direction of flow along the plate. 19. The surface according to claim 17, on which around the recesses are located recesses with smaller longitudinal, transverse dimensions and depths. 20. The surface according to p. 17, on which on its other side there are protrusions corresponding to the recesses. 21. The surface according to claim 17, on which on the other side of the plate are ribs oriented along the plate in the direction of flow. 22. The surface of claim 17, wherein the recesses are located on the other side of the plate symmetrically or asymmetrically with respect to the recesses of the main side. 23. The surface according to claim 17, which contains an additional surface of the plate with recesses, located relative to the main surface with the formation of a heat exchange channel, while the surface of the plates with recesses are facing each other and are located in parallel due to the spacing elements in the form of hemispherical, conical, cylindrical protrusions or other forms. 24. The surface of the pipe according to claim 9, on which the recesses along the pipe and across the pipe are staggered or corridor. 25. The surface according to p. 24, on which the size of the recesses and their depth increases or decreases in the direction of flow along / or across the pipe. 26. The surface according to p. 24, on which on the inner surface of the pipe there are protrusions having a second-order surface. 27. The surface according to claim 24, on which recesses are located on the inner surface of the pipe, the size and depth of which increase or decrease in the direction of flow along or across the pipe. 28. The surface according to p. 24 or 27, on which on the inner surface of the pipe are longitudinal ribs with recesses on their surface. 29. The surface according to claim 24 or 27, on which transverse ribs with recesses are located on the inner surface of the pipe. 30. The surface according to claim 24 or 27, on which a curved twisted tape with recesses is located inside the pipe. 31. The surface according to p. 24, on which on the inner surface of the pipe are recesses symmetrically or asymmetrically relative to the recesses on the outer surface.