RU2799259C1 - Nozzle for spraying viscous liquids - Google Patents

Abstract

FIELD: liquid atomization technique.

SUBSTANCE: invention relates to injectors with direct injection of liquid fuel into the combustion space in a drip state, and can be used in various areas of production activity, in engine building, chemical and food industries, in fuel-burning units. The nozzle for spraying viscous liquids comprises a housing, which is formed by two cylinders of different outer diameters so that the end of the cylinder of smaller diameter is attached to it through the central hole in the plugged end of the cylinder of larger outer diameter, and the inner diameter of the cylinders is the same. The outer end of the cylinder of larger diameter is provided with a cover. An elongated cylindrical element is coaxially inserted into the housing, close to its inner walls, inside which a fuel channel is made. One end of the elongated cylindrical element protrudes outward from the housing and serves to supply pressurized fuel. In the middle part, the elongated cylindrical element is made with a protrusion, the outer diameter of which is equal to the inner diameter of the housing. The other end of the elongated cylindrical element, located inside the cylinder of a larger outer diameter, is made with a protrusion in the form of an elongated ellipsoid of revolution truncated on both sides, the outer end of which is cut inwards, forming a rounded edge. Between the outer surfaces of the elongated cylindrical element and the inner surfaces of the housing, a cavity is formed, which is connected through the first fitting on the side wall of the housing to a container filled with a primary atomizer under pressure. The protruding part of the housing in the form of a cylinder of larger outer diameter is made solid with an inner annular coaxial channel, which is connected to a container filled with a secondary spray under pressure by a second fitting in the side part of the housing. In the housing cover, opposite the rounded edge of the end of the elongated cylindrical element, a hole is made in the form of a truncated cone, the radius of which on the outer surface of the cover is less than the radius on the inner surface of the cover by an amount equal to the thickness of the cover, with the formation of an annular gap between the rounded edge of the elongated element and the housing cover for exit outside of the primary atomizer. Along the circumference of the cover, at an equal distance between themselves and from the centre of the fuel channel, n holes are made, each of which is connected to the annular coaxial channel by its channel parallel to the axis of the fuel channel.

EFFECT: expanding the range of technical tools for spraying viscous liquids.

1 cl, 3 dwg, 1 tbl

Description

The invention relates to the technique of spraying a liquid, for example, liquid fuels, namely to nozzles with direct injection of liquid fuel into the combustion space in a drip state and can be used in various areas of production, in engine building, chemical and food industries, in fuel-burning units.

Known nozzle for spraying viscous liquids [EN 2253802 C1, IPC F23D11/12 (2000.01), publ. 06/10/2005], containing a housing with a central fuel channel and a coaxial annular sprayer supply channel connected to a mixing chamber, part of which is made of a conical shape. The annular row of axial channels of the primary atomizer and the annular row of channels of the secondary atomizer are connected at the inlet to the coaxial annular atomizer supply channel, and at the outlet, respectively, to the nozzles of the primary atomizer and the nozzles of the secondary atomizer. Around the circumference at the outlet of the conical part of the chamber, nozzles of the tertiary atomizer are made, while the nozzles of the tertiary atomizer are installed at an angle δ≥15° relative to the vertical axis of the nozzle and at an angle φ≥15° relative to its plane.

The disadvantages of the known nozzle are unsatisfactory dispersion of the spray (~200 μm), as well as a large opening angle of the torch (up to 160°).

Known nozzle for spraying viscous liquids [RU 2039910 C1, IPC F23D11/10 (1995.01), publ.: 07/20/1995], containing a housing with a central fuel channel and a coaxial annular spray supply channel connected to the mixing chamber, as well as radial nozzles of the primary atomizer and nozzles of the secondary atomizer communicating the annular channel with the mixing chamber. The housing has an annular row of axial channels connected at the inlet to the mixing chamber, and at the outlet - to the radial nozzles of the primary atomizer, the longitudinal axes of which are located at a distance from the outlet section of the fuel channel, exceeding their diameter by 1.5-3.0 times. The outlet sections of said radial nozzles are located from the axis of the housing at a distance exceeding their diameter by 4-6 times. Nozzles of the secondary atomizer are axial and displaced in the circumferential direction relative to the axial channels, while their longitudinal axes are located from the body axis at a distance exceeding their diameter by 1.5-3.0 times.

The disadvantages of the known nozzle are unsatisfactory dispersion of the spray (~200 μm).

The technical result of the invention is the expansion of the arsenal of technical means for spraying viscous liquids.

The proposed nozzle for spraying viscous liquids, as well as in the prototype, contains a housing with a coaxial annular sprayer supply channel and a central fuel channel.

According to the invention, the nozzle body is formed by two cylinders of different outer diameters so that the end of the cylinder of a smaller diameter is attached to it through a central hole in the plugged end of the cylinder of a larger outer diameter, and the inner diameter of the cylinders is the same. The outer end of the cylinder of larger diameter is provided with a cover. An elongated cylindrical element is coaxially inserted into the housing, close to its inner walls, inside which a fuel channel is made. One end of the elongated cylindrical element protrudes outward from the housing and serves to supply pressurized fuel. In the middle part, the elongated cylindrical element is made with a protrusion, the outer diameter of which is equal to the inner diameter of the housing. The other end of the elongated cylindrical element, located inside the cylinder of a larger outer diameter, is made with a protrusion in the form of an elongated ellipsoid of revolution truncated on both sides, the outer end of which is cut inward , forming a rounded edge. Between the outer surfaces of the elongated cylindrical element and the inner surfaces of the housing, a cavity is formed, which is connected through the first fitting on the side wall of the housing to a container filled with a primary atomizer under pressure. The protruding part of the housing in the form of a cylinder of a larger outer diameter is made solid with an inner annular coaxial channel, which is connected to a container filled with a secondary spray under pressure by a second fitting in the side part of the housing. In the housing cover, opposite the rounded edge of the end of the elongated cylindrical element, a hole is made in the form of a truncated cone, the radius of which on the outer surface of the cover is less than the radius on the inner surface of the cover by an amount equal to the thickness of the cover, with the formation of an annular gap between the rounded edge of the elongated element and the housing cover for exit outside of the primary atomizer. Along the circumference of the cover, at an equal distance between themselves and from the center of the fuel channel, n holes are made, each of which is connected to the annular coaxial channel by its channel parallel to the axis of the fuel channel.

By dividing the atomizer flow into two (primary and secondary), a phased crushing of the fuel flow exiting the fuel channel is carried out, which achieves the maximum interaction between the fuel and the atomizer, which ensures its high-quality atomization, bringing it closer to a monodisperse fine state. Additionally, an increase in the speed of movement of fuel droplets is achieved, as well as a decrease in the values of the jet opening angles and its deviation from the original trajectory.

An increase in the volume fraction of small droplets in the flow provides faster ignition of fuel droplets in the combustion chambers, since it is known that the smaller the droplet size, the shorter the ignition delay time [V. Salomatov, G. Kuznetsov, S. Syrodoy, N. Gutareva, Effect of high-temperature gas flow on ignition of the water-coal fuel particles, Combust. flame. 203 (2019) 375-385].

Increasing the speed of droplets provides faster filling of the combustion chamber with atomized fuel.

Reducing the jet opening angle is necessary when using pre-furnaces for preliminary heating of droplets before they are fed into the main combustion chamber . If the pre-furnace is a cylindrical extended channel, then a large jet opening angle leads to the settling of a large part of the drops on its walls. Reducing the jet deviation angle from the original trajectory provides predictable spraying, since with a large deflection angle, some of the droplets, due to a change in their trajectory, will settle in the lower part.

In FIG. 1 shows the appearance of a nozzle for spraying viscous liquids.

In FIG. 2 shows a longitudinal section of a nozzle for spraying viscous liquids A-A, a side view and a cross section B-B.

In FIG. 3 shows a diagram of spraying a viscous liquid.

Table 1 (see the graphic part) shows the results of spraying a viscous liquid - water-coal fuel.

The nozzle contains a housing formed by two cylinders of different outer diameters so that the end of the cylinder of smaller diameter 1 (Fig. 1) through the central hole in the plugged end of the cylinder of larger outer diameter 2 is attached to it. The inner diameter of cylinders 1 and 2 is the same. The outer end of the cylinder of larger diameter 2 is provided with a cover 3.

An elongated cylindrical element (Fig. 2) is coaxially inserted into the housing, close to its inner walls, inside which a fuel channel 4 is made. One end of the elongated cylindrical element protrudes out of the housing and serves to supply fuel under pressure. In the middle part, the elongated cylindrical element is made with a ledge, the outer diameter of which is equal to the inner diameter of cylinders 1 and 2. the end of which is cut inward , forming a rounded edge.

Between the outer surfaces of the elongated cylindrical element and the inner surfaces of the housing, a cavity 7 is formed, which is connected through the first fitting 8 on the side wall of the housing to a container filled with a primary atomizer under pressure, for example, air.

In the cover 3 of the body, opposite the rounded edge of the end of the elongated cylindrical element, a hole 9 is made so that an annular gap is formed between the rounded edge of the elongated element and the cover 3 of the body for the primary atomizer to go outside.

Hole 9 in the housing cover is made in the form of a truncated cone so that its radius on the outer surface of the cover 3 is less than its radius on the inner surface of the cover 3 by an amount equal to the thickness of the cover 3.

The protruding part of the body in the form of a cylinder of a larger outer diameter is made solid with an internal annular coaxial channel 10, which is connected to a container filled with a secondary spray under pressure by a second fitting 11 in the side of the body. Air can be used as a secondary atomizer.

In the cover 3 around the circumference, at an equal distance between themselves and from the center of the fuel channel 4, opposite the annular coaxial channel 10, n holes 12 are made, each of which is connected to the annular coaxial channel 10 by its channel 13, made parallel to the axis of the fuel channel 4. Number of holes 12 performed based on the values of the required mass flow rate of the secondary atomizer, for example, four, as shown in Fig. 1.

The nozzle works as follows. A viscous fuel, such as coal-water fuel, is supplied through the central fuel channel 2 with a mass flow rate in the range of 100-500 kg/h. The primary atomizer, for example, air, is supplied from the nozzle 8 of the primary atomizer with a mass flow rate of 35-70 kg/h simultaneously with the supply of the secondary atomizer, for example, air, from the nozzle 11 of the secondary atomizer with a flow rate of 20-50 kg/h. In this case, the flow of the atomizer, flowing out of the hole 9, creates a discharge of the atomizer, which leads to the primary crushing of the fuel jet leaving the fuel channel 4 into drops. The droplet flow formed as a result of primary crushing at a distance of about 80-100 mm from the cover 3 of the nozzle is subjected to secondary crushing due to interaction with the jets of the secondary atomizer emerging from holes 12. As a result of this interaction, large (more than 100 microns) drops are crushed into smaller ones, droplet speed increases. Additionally, due to the impact on the atomized fuel flow by a group of jets of the secondary atomizer emerging from the holes 12, the angle of deviation of the jet from the original trajectory decreases - the flow is stabilized, and the opening angle of the jet is also reduced.

A series of experiments was carried out to numerically estimate the values of spray characteristics (volume fraction of small droplets, droplet velocity, jet opening angle, jet deviation angle from the initial trajectory). Experiments were performed for cases when the secondary atomizer was not used, as well as when it was used (air supply). 3 compositions of water-coal fuels were used as a spray liquid. The first composition was a mixture of tap water and coal enrichment waste - coal filter cake grade D (mass concentration of each component was 50%). The second composition was a mixture of tap water, waste coal preparation - coal filter cake grade D and rapeseed oil (the mass concentration of the components was 45:50:5%). The third composition was a mixture of tap water, waste coal preparation - coal filter cake grade D and sawdust (the mass concentration of the components was 50:45:5%). Water-coal fuel was supplied through the fuel channel 4 with a mass flow rate of 140 kg/h. Air, as primary and secondary atomizers, was supplied through the first 8 and second 11 fittings through flexible hoses connected to the outlets of the receivers of the PATRIOT EURO 24/240 air compressors (type - piston oil; operating pressure - 0.1-0.8 MPa; receiver volume - 24 l). To register the spraying characteristics, a video recording system was used, which included: a Multiled PT-V9 GS Vitec searchlight (number of LEDs - 24; luminous flux - 7700 Lm; power - 84 W, scattering angle - 30°); high-speed video camera "Phantom MIRO M310" (resolution 1280 × 800 pixels; shooting frequency - 3200 frames per second; exposure time - 1 μs; image resolution - 12 bits); set of lenses: "SIGMA 50 mm 1: 2.8D MACRO EX" (focal length - 50 mm, relative aperture - 2.8); "Nikon Micro-Nikkor 200mm f / 4D ED-IF A" (focal length - 200 mm, relative aperture - 4). Simultaneously with the supply of coal-water fuel, a video recording of the fuel atomization process was started using a personal computer, using a high-speed video camera, and the area around the water-coal fuel droplets was illuminated using an LED spotlight installed opposite the video camera. The resulting video images were transferred to a personal computer, where they were processed, during which the spray characteristics were determined. Software used: "Phantom Camera Control" and "ActualFlow". Data processing was carried out by analogy with that described in [G.V. Kuznetsov, P.A. Strizhak, T.R. Valiullin, R.S. Volkov, Atomization behavior of composite liquid fuels based on typical coal processing wastes, Fuel Process. Technol. 225 (2022) 107037].

Table 1 shows the values of the characteristics of water-coal fuel spraying established by the results of experiments. The results of studies of the characteristics of the atomization of water-coal fuel (the volume fraction of small drops, the velocity of the drops, the angle of the jet opening, the angle of deviation of the jet from the original trajectory), obtained using the method of high-speed video recording, make it possible to carry out a comparative analysis of the characteristics of the atomization of water-coal fuel without using, as well as when using secondary atomizer. So it can be seen that the use of a nozzle with a secondary atomizer leads to an increase in the volume fraction of small droplets in the flow, an increase in the speed of the droplets, a decrease in the angle of deviation of the jet from the original trajectory, as well as the angle of opening of the jet.

Claims (1)

Nozzle for atomizing viscous liquids, comprising a body with a coaxial annular atomizer supply channel and a central fuel channel, characterized in that the body is formed by two cylinders of different outer diameters so that the end of the cylinder of a smaller diameter is attached to it through a central hole in the plugged end of the cylinder of a larger outer diameter , moreover, the inner diameter of the cylinders is the same, and the outer end of the cylinder of a larger diameter is provided with a cover, while an elongated cylindrical element is coaxially inserted into the housing, close to its inner walls, inside which a fuel channel is made, and one end of the elongated cylindrical element protrudes out of the housing and serves to supply fuel under pressure, in the middle part the elongated cylindrical element is made with a protrusion, the outer diameter of which is equal to the inner diameter of the body, and the other end of the elongated cylindrical element, located inside the cylinder of a larger outer diameter, is made with a protrusion in the form of an elongated ellipsoid truncated on both sides rotation, the outer end of which is cut inward , forming a rounded edge, between the outer surfaces of the elongated cylindrical element and the inner surfaces of the housing, a cavity is formed, which is connected through the first fitting on the side wall of the housing to a container filled with a primary pressure atomizer, the protruding part of the housing in the form of a larger cylinder external diameter, is made solid with an inner annular coaxial channel, which is connected by a second fitting in the side part of the housing to a container filled with a secondary spray under pressure; the outer surface of the cover is less than the radius on the inner surface of the cover by an amount equal to the thickness of the cover, with the formation of an annular gap between the rounded edge of the elongated element and the housing cover for the primary atomizer to go out, around the circumference of the cover, at an equal distance between themselves and from the center of the fuel channel, made n holes, each of which is connected to the annular coaxial channel by its channel parallel to the axis of the fuel channel.

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