RU2252826C1 - Rotary-pulse apparatus - Google Patents

Abstract

FIELD: devices for forming pulse oscillations in liquid medium for obtaining homogeneous emulsions and dispersed systems.

SUBSTANCE: proposed apparatus has housing with suction branch pipe for delivery of suspensions and delivery branch pipe for discharge of suspensions being treated; apparatus is also provided with rotor and stator located coaxially inside it. Rotor and stator have holes: holes in rotor are made in form of rectangular tubes and holes in stator are made in form of widening rectangular flat tubes. Proposed apparatus enhances efficiency of treatment of suspensions not only due to generation of pressure pulses but due to high-frequency oscillations formed at collapse of cavitation bubbles.

EFFECT: enhanced efficiency.

6 dwg

Description

The invention relates to a device for creating pulsed oscillations in a flowing liquid medium, mixing in systems “liquid - liquid”, “liquid - solid” and can be used in chemical, oil, pharmaceutical, engineering, mining and other industries for and intensification of various physicochemical, hydromechanical and heat and mass transfer processes (for example, for the preparation of water-coal fuel, water-hydrocarbon fuel, etc.).

A device, a rotary-pulse apparatus, patent RU No. 2179896 of 02.27.2000, in which a rotor and a stator are coaxially mounted in the housing with two cylindrical side walls in which radial channels are made, the channels in the outer wall of the stator are coaxial along the radial axis, is known. with channels in the inner wall of the stator, and the channels in the outer wall of the rotor are shifted relative to the channels in the inner wall of the rotor with an interval (a / 4 - 3a / 4) in the circumferential direction in the direction of rotation of the rotor, where a is the width of the channels of the rotor and stator.

A disadvantage of the known device is that the selected shape of the holes of the rotor and stator is not effective enough for the occurrence of hydrodynamic cavitation.

A device, an acoustic emitter, is known from Russian patent No. 2149713 dated 05/27/2000, in which, in a housing having inlet and outlet nozzles and coaxially mounted cylindrical rotor and stator with channels on the side walls, the stator is installed inside the rotor and the machined liquid is supplied from the outer surface of the rotor, the number of stator and rotor channels is equal to each other, and the channels in the rotor are made to the radius of the rotor at an angle

where ω is the angular velocity of the rotor (rad / sec);

R _cp is the average radius of the rotor (m);

a - the width of the rectangular channel of the rotor (m);

h is the height of the rotor channel (m);

Q - fluid flow through the emitter (m ³ / s).

A disadvantage of the known device is that for the suspension to flow through the device, it is necessary to increase the pressure in the suspension at the inlet opening to limits exceeding the back pressure exerted by the suspension, which is expelled by centrifugal force from the rotor holes to the stator holes. The use of such a device will significantly increase the specific energy consumption per unit of the processed suspension.

A device is known, a high-frequency multi-row rotary-pulse apparatus, Russian patent No. 2179895 dated 02.27.2002, in which a hollow stator and rotor are made in the form of bodies of revolution in a housing with an annular working chamber, with hollow stator and rotor in the side walls of which are made through channels located in rows, with the number of rows of at least one, while the channels of the rotor and stator are made in such a way that when the channels of the first row of the rotor are aligned with the channels of the first row of the stator, the channels of the other rows of the rotor are shifted you are in the circumferential direction relative to the channels of the respective rows of the stator by an amount determined from the ratio

d _n = 0.1K ₁ a (n-1)

where d _n is the shift in the circumferential direction of the rotor channels in the row with the number n relative to the stator channels in the row with the number n for such an arrangement of the rotor and stator when the channels of the first row of the rotor and stator are combined;

a - channel width;

K ₁ - coefficient, which is selected from the range of 0.9 <K ₁ <1.1.

The disadvantages of the known device is that for the effective operation of the device requires excess pressure at the inlet of the apparatus, within 3-10 atm, at which pulses of a suspension of known intensity and frequency range are formed.

A device is known, a hydrodynamic emitter, Russian patent No. 2205073 dated 05/27/2003, having a nozzle and a resonant oscillating device with slots, equipped with a housing consisting of two disks, each of which has a central hole, an end annular groove and an internal, made on the passage to the annular groove is an annular groove, the disks face each other, forming an annular cavity from the end annular grooves and from the annular grooves, an internal circular nozzle, a resonant oscillating device cerned is designed as a set in the central opening of the circular nozzle against the inner annular resonant plate in which radial slits.

Positive in the known device is that there are no rotating working bodies.

A disadvantage of the known device is that such a device can only be used in liquid-liquid systems, and if there are solid components in the suspension, the ring resonance plate will wear out very quickly and then cease radiation due to frequency violation.

The technical problem to which the invention is directed is to create a device in which the conditions for the occurrence of fluctuations are provided not only from interruption of the flow of the processed suspension when the rotor and stator holes are displaced, but also the use of such shapes and sizes of the rotor and stator holes that provide stable conditions hydromechanical cavitation in order to intensify emulsification and ensure the conditions for the intensive course of many physical and chemical processes.

The formation of two cavitation zones (unlike all known devices) will lead to an intensification of the processes of emulsification and dispersion of the medium being processed, and alternating hydraulic shocks in the rotor holes and adjustable static pressure in the medium outlet pipe in the stator holes will ensure the completion of the thermodynamic life cycle of cavitation bubbles in the holes stator and rotor. Shock waves and cumulative jets formed during the “collapse” of cavitation bubbles, which have high energy, will provide highly efficient emulsification and dispersion of solid particles of the suspension.

This object is achieved in that in a rotary-pulse apparatus containing a housing 1 with a nozzle (Fig. 1, 2) for supply and a nozzle 7 for removal of the emulsified medium, inside of which the rotor 3 on the shaft 4 and the stator 2 are concentrically located to each other the peripheral part of the rotor, in the annular nozzle, the holes are made in the form of flat rectangular pipes. The holes in the stator are made in the form of flat rectangular pipes, expanding towards the housing with one ledge located along the rotor.

When the suspension passes through the holes located in the annular nozzle of the rotor 5, having a flat rectangular shape, low pressure zones are formed (zone A in Fig. 3), in which cavitation bubbles form.

At the moment of combining the rotor and stator openings, the suspension flow rushes under the influence of kinetic energy into the openings of stator 2, “sticks” to the wall and bends around the protrusion of the expanding part to form a cavitation zone (zone B in Fig. 3). With full alignment of the holes, and then in the phase of their overlap, the suspension flows along the same wall under the influence of the Coanda effect.

The pressure resulting from the condensation of vapor-gas and cavitation bubbles can be determined by the formulas.

1. Condensation of gas bubbles.

where R ₀ is the radius of the initial value of the gas bubble, mm;

R is the final value of the gas bubble, mm;

P ₀ - hydrostatic pressure in the liquid, kg / cm ² ;

P is the pressure that occurs in the center of condensation of the cavitation bubble, kg / cm ² .

и Р₀=1 кг/см² получаем Р=1260 кг/см².For example: when

and P ₀ = 1 kg / cm ² we get P = 1260 kg / cm ² .

2. The pressures arising from the condensation of steam navigation bubbles are determined by the formula

where β is the compressibility of the liquid, kg / cm ² (for water β = 50 · 10 ^-6 kg / cm ² ).

получаем Р=10300 кг/см².At the same values of P ₀ = 1 kg / cm ² and

we get P = 10300 kg / cm ² .

получаем Р=498800 кг/см².When P ₀ = 10 kg / cm ² and

we get P = 498800 kg / cm ² .

It is known that cavitation in a liquid occurs the earlier, the more the liquid is contaminated with solid particles.

This is due to the fact that a thin layer of air is adsorbed on the surface of solid particles, the particles of which, when they enter the zone of reduced pressure, serve as foci that contribute to the occurrence of cavitation. Cavitation bubbles arising on the surfaces of particles of emulsifiable and dispersible materials are deformed during movement of the processed hydraulic mixture. During condensation of deformed cavitation bubbles, cumulative streams arise, providing intensive mixing and emulsification of the treated medium.

The pressures arising at the disappearance points of cavitation bubbles generate shock waves in the fluid. The shock wave decays rapidly as it moves away from the collapsed bubble. However, if the surface of a solid is near the bubble, the shock wave reaching it has sufficient intensity to deform this surface. In the cavitation zone, a huge number of bubbles appear and collapse. Therefore, one and the same surface or particle of a solid body experiences repeatedly repeated pulses of mechanical stress, which lead to fatigue and subsequent destruction of these particles.

Figure 1 shows a longitudinal section of a rotary-pulse apparatus, consisting of the following parts:

1 - hollow body;

2 - stator ring with holes;

3 - a rotor made in the form of a centrifugal impeller;

4 - rotor shaft;

5 - a rotor ring with holes;

6 - suction pipe of the housing.

Figure 2 shows a cross section of a rotary pulse apparatus, which additionally shows:

7 - pipe for removal of the processed medium;

8 - the suction cavity of the rotor;

9 - pressure regulator.

Figure 3 shows the conditions for the occurrence of hydrodynamic cavitation in the holes of the rotor ring 5 and the stator ring 2 (zone A and zone B) when the holes are aligned.

Figure 4 shows the conditions for the occurrence of water hammer in the holes of the rotor ring 5 and the condensation of the navigation bubbles in the holes of the stator ring 2 under the action of excess pressure P ₂ supported by the pressure regulator 9.

Figure 5 shows the position of the rings of the rotor and stator at the time of alignment of the holes.

Figure 6 shows the position of the rotor and stator when the holes do not match.

The rotor 3 is equipped with vanes, like a centrifugal pump, designed to communicate the centrifugal force of the processed fluid and provide pressure P ₁ in front of the flat rectangular holes of the rotor 3.

The pipe 7 for the removal of the processed medium is equipped with a pressure regulator 9, which provides the necessary pressure P ₂ in the pressure cavity of the rotary pulse apparatus.

Rotary-pulse apparatus, depending on the application, can be made of any size and performance.

The design of the rotary-pulse apparatus ensures a break in the continuity of the processed suspension or hydraulic mixture, which increases the vibration energy by 40%, and the optimal ratio of the rotor and stator bore sizes provides conditions for the stable occurrence of cavitation bubbles that condense, “collapse” under conditions of hydraulic shocks in the bore of the rotor and under the influence of excess pressure in the holes of the stator.

The rotary-pulse apparatus operates as follows.

When the rotor 3 is rotated, the suspension to be processed through the suction pipe 6 of the hollow body 1 enters the suction cavity 8 and is sent to the rotor 3, made in the form of an impeller of a centrifugal pump. The rotor 3, mounted on the shaft 4, rotating, acts with the blades on the suspension, discards it to the peripheral part, to the annular nozzle 5 and gives it kinetic energy.

In the annular nozzle 5 of the rotor, the suspension passes through many flat rectangular openings. Possessing great kinetic energy, the suspension flow, passing through flat rectangular holes, forms low pressure zones in them (zone A in Fig. 3). Not only zone A, but also the transit stream of the suspension within this region, is characterized by the presence of a vacuum, which ensures saturation of the suspension with cavitation bubbles.

(N _vac ) _max = (0.75-0.8) P ₁ -P ₂ ,

where (N _vac ) _max is the maximum vacuum in zone A;

P ₁ - pressure in the impeller in front of the rotor holes;

P ₂ - pressure in the pressure region of Fig.2.

When the pressure in zone A and the transit stream of the treated suspension decrease below the saturated vapor pressure of one of the components, the suspension boils intensively, forming navigation bubbles, and saturates the transit stream with them within this zone. After the passage of zone A in the transit jet, the pressure rises and the cavitation bubbles condense, forming the first wave of cavitation shocks. Shock waves intensively stir the suspension, deform the surface of the solid particles of the slurry slurry, and the liquid penetrating the microcracks under the influence of the shock waves increases them or destroys the named particles.

At the time of alignment of the rotor and stator holes, the liquid passing through the step of the expanding holes forms low pressure zones in zones B of the stator ring 2 (Fig. 3), in which cavitation bubbles form.

At the time of overlapping of the rotor holes with the side walls of the stator, a sharp increase in pressure occurs along the entire length of the rectangular flat rotor holes (direct hydraulic shock), which is amplified by shock waves from the “collapse” of cavitation bubbles in zone A of the rotor ring 5 (Fig. 4).

In zone B, an intensive “collapse” of cavitation bubbles provides a constant overpressure P ₂ supported by a pressure regulator 9 (FIG. 2).

An increase in the intensity of emulsification, dispersion, as well as the occurrence of physicochemical processes due to the rupture of the continuity of the treated suspension and the consequent cavitation action on the components of the suspension in the holes of the rotor and stator contributes to an increase in the productivity of the rotary-pulse apparatus.

A rotary-pulse apparatus makes it possible to obtain homogeneous finely dispersed suspensions, to prepare various emulsions, to ensure the occurrence of many physicochemical reactions requiring elevated pressures and temperatures, to mix immiscible liquids, and to activate processed suspension components.

The thermal energy released as a result of the “collapse” of cavitation bubbles allows many processes to be carried out without preliminary heating of the suspension components at negative temperatures.

List of references

1. Patent of Russia No. 2179896 dated 02.27.2000.

2. Russian Patent No. 2149713 dated 05/27/2000.

3. Patent of Russia No. 2179895 dated 02.27.2000.

4. Patent of Russia No. 2205073 dated February 27, 2000.

5. T.M.Bashta. “Engineering Hydraulics”, Moscow: Engineering, 1971, pp. 44 ... 49, 118, 349, 375, 379 ... 381, 509 ... 512.

6. L.I. Bogomolov, K.A. Mikhailov. “Hydraulics”, Moscow: Stroyizdat, 1972, p. 87 ... 92, 142 ... 150, 398 ... 405.

7. R.R. Chugaev. “Hydraulics”, Moscow: Energy, Leningrad Branch, 1971, p. 14 ... 17, 28 ... 33, 64 ... 74, 85 ... 88, 135 ... 140, 163. ..167, 277 ... 286, 307 ... 314.

8. I. Pirsol. “Cavitation”, trans. from English Ph.D. Yu.F. Zhuravleva, Moscow: Mir, 1975, p. 9 ... 20, 22 ... 25, 36 ... 50, 69 ... 89.

9. M.A. Lavrentiev, B.V. Shabat. “Problems of hydrodynamics and their mathematical models”, Moscow: Nauka, 1973, p. 350, 352 ... 357.

10. B.B. Mayer. “Cumulative effect in simple experiments”, Moscow, 1989, pp. 44, 47, 92 ... 97, 175 ... 177.

11. E.I. Zababakhin, I.E. Zababakhin. "The phenomena of unlimited cumulation." M .: Nauka, 1988, pp. 11-17, 20-30.

12. I.Sh. Fedotkin, A.F. Nelegin. “The use of cavitation in technological processes”, Kiev: Vishcha school, 1984, pp. 12-13.

13. Doctor of Technical Sciences, Professor B.A. Agranata. “Ultrasonic technology”, Moscow: “Metallurgy”, 1974, pp. 144-150, 211-220, 400-413.

Claims (1)

A rotary-pulse apparatus having a hollow body with a suction pipe for supplying suspensions and a discharge pipe for removing processed suspensions, a rotor in the form of a centrifugal wheel with holes along the periphery and a stator with holes installed coaxially to the rotor, characterized in that, for the purpose of intensification of emulsification, dispersion and acceleration of physicochemical processes due to hydrodynamic cavitation, the holes in the rotor are made in the form of flat rectangular pipes, and the holes I am in the stator - in the form of a ledge of expanding rectangular flat pipes.

Images