CN113006949A

CN113006949A - Spiral oil pipe type three-gas-path air atomizing nozzle

Info

Publication number: CN113006949A
Application number: CN202110238184.5A
Authority: CN
Inventors: 张群; 王晓燕; 王紫欣; 马晓曦; 高耀红
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2021-03-04
Filing date: 2021-03-04
Publication date: 2021-06-22
Anticipated expiration: 2041-03-04
Also published as: CN113006949B

Abstract

The invention provides an air atomizing nozzle structure. The nozzle adopts a scheme of combining an inner ring air passage, an outer ring air passage and a spiral oil pipe so as to solve the problem of insufficient fuel atomization at present. The mixing cavity and the inner cavity of the lining sleeve are integrally and gradually contracted, and hemispherical disturbing fluids are arranged on the wall surfaces of the mixing cavity and the lining sleeve; the spiral oil pipe and the inner ring main and auxiliary gas circuit are arranged in the mixing cavity, and the bushing with the throat and the outer wall of the mixing cavity form an outer ring gas circuit; the diameter of the central air pipe communicated with the auxiliary air passage and the spiral diameter of the spiral oil pipe wound outside the central air pipe are gradually reduced along the axial direction, and the wall surfaces of the central air pipe communicated with the auxiliary air passage and the spiral oil pipe are provided with spray holes. The fuel oil is accelerated to be sprayed out from the spray holes under the action of centrifugal force and pressure difference, and is atomized into small oil drops at one time; then carrying out secondary atomization under the shearing impact of the inner ring secondary air flow, and expanding the secondary atomization downstream under the blowing of the high-speed main air flow; and finally, carrying out tertiary atomization on the fuel oil fine droplets and the outer ring airflow at the throat of the bushing to form uniform oil-gas mixed gas. The structure effectively enhances the atomization effect of the fuel oil and reduces the emission of pollutants.

Description

Spiral oil pipe type three-gas-path air atomizing nozzle

Technical Field

The invention belongs to the field of combustion chambers of aero-engines, and particularly relates to a spiral oil pipe type three-gas-path air atomizing nozzle.

Background

The nozzle is an important part in a combustion chamber of an aircraft engine, and the main function of the nozzle is to realize fuel atomization, so the performance of the nozzle has great influence on the combustion process. At present, nozzles used inside combustion chambers can be divided into two categories according to the atomization principle: pressure atomization and air atomization. Pressure atomization is to convert pressure potential energy into power potential energy, so that atomization is realized through strong shearing action between gas and liquid phases; the air atomization takes air as a medium, and the air and the liquid fuel are collided, extruded, sheared, torn and the like, so that the liquid fuel is crushed.

With the innovation of the technology of the aero-engine, the combustion efficiency of the combustion chamber is effectively improved, the pressure ratio and the temperature rise of the combustion chamber are improved, the advantages of the air atomizing nozzle are gradually highlighted under a certain working condition, the air atomizing nozzle can ensure that fuel oil and air flow are fully mixed, the advantages that a low oil supply pressure and an outlet temperature field are not sensitive to fuel oil change and the like can be achieved, and the air atomizing nozzle is frequently used in the aero-engine with higher performance. The traditional air atomizing nozzle structure enables fuel to be subjected to the action of inner and outer swirling air shearing forces in the downstream flowing process to form smaller atomized particles. The air atomizing nozzle has the defects that the air atomizing nozzle has higher requirements on a processing technology, and simultaneously, the quality of fuel oil atomization is poor easily due to one-time atomization, so that the temperature distribution is uneven, and the combustion efficiency of the whole combustion chamber is influenced.

The invention utilizes the mode of combining the spiral oil pipe and the three gas paths to carry out primary atomization with the inner ring main and auxiliary gas flows in the mixing cavity, so that oil drops form smaller atomized particles, and then secondary atomization is carried out with the outer ring gas flow at the throat of the bushing to form finer oil mist, thereby effectively improving the air atomization effect; the inclined oil injection hole on the spiral oil can solve the problem of uneven fuel space distribution, so that the combustion efficiency is improved, and the pollutant emission is reduced.

Disclosure of Invention

The invention aims to solve the technical problem of providing a spiral oil type three-gas-path air atomizing nozzle so as to solve the problems of insufficient fuel oil atomization, uneven fuel space distribution and the like in the prior art. In the technology, fuel oil is uniformly sprayed to the periphery through an inclined oil spraying hole of a spiral oil pipe and is atomized for the first time to form small oil drops; then the fuel oil is impacted and sheared with the high-speed airflow ejected by the central air pipe jet orifice, so that the fuel oil is atomized for the second time; the main airflow of the mixing cavity interferes with the fluid action, the turbulence degree is improved, the small oil drops are prevented from remaining on the wall surface to a large extent, the small oil drops are blown at a high speed of the main airflow and extend to the downstream until the throat of the lining, the mixed gas at the moment is accelerated in the narrow channel and is collided and torn with the outer ring airflow, the oil drops are atomized for three times to form uniform oil mist, the fuel oil atomization effect is further optimized, the smoke intensity and the heat radiation quantity are greatly reduced, the pollutant emission is reduced, and the combustion efficiency of the combustion chamber is effectively improved.

Technical scheme

The invention aims to provide a spiral oil pipe type three-gas-path air atomizing nozzle.

The technical scheme of the invention is as follows:

the utility model provides a three gas circuit air atomizing nozzle of spiral oil pipe formula, has adopted three gas circuits and the atomizing scheme of cubic, its characterized in that: on the basis of the existing mixing cavity and lining structure, the outlet of the mixing cavity is set as the throat of the lining, and hemispherical disturbance fluid is distributed on the wall surfaces of the mixing cavity and the lining; an inner ring auxiliary gas path is communicated in the central gas tube and is arranged in the center of the mixing cavity, and gas injection holes with the same size are uniformly distributed on the wall surface of the gas tube; spiral oil pipe winding is in the central trachea outside, and same axis is shared to both, and the same nozzle opening of size is being distributed equally on the oil pipe wall, and the afterbody sets up the tapered oilhole that contracts.

The spiral oil pipe type three-gas path air atomizing nozzle is characterized in that: the hemispherical turbulent fluids on the straight section of the mixing cavity have the same size and are arranged in a fork arrangement mode; the contraction section is provided with the same turbulence bodies, the arrangement mode (in-line arrangement or cross arrangement) of the turbulence bodies depends on the contraction angle, and the distribution density of the turbulence bodies can be slightly smaller than that of the straight section. The joints of the turbulent flow bodies and the wall surfaces are in arc transition.

The spiral oil pipe type three-gas path air atomizing nozzle is characterized in that: the distribution of the spherical disturbing fluid on the inner wall of the lining is similar to that of the mixing cavity, the straight section is arranged in a staggered mode, the contraction section can be arranged in a staggered mode, and the distribution density can be smaller than that of the straight section.

The spiral oil pipe type three-gas path air atomizing nozzle is characterized in that: the inner diameter of the central air pipe is linearly reduced along the axial direction; the air injection holes on the tube wall have the same size and are spirally wound and distributed on the wall surface of the central air tube in equal distance and equal diameter.

The spiral oil pipe type three-gas path air atomizing nozzle is characterized in that: the external spiral diameter of the spiral oil pipe is linearly reduced, the thread pitch is constant, and the diameter of the internal pipeline is unchanged; the head part of the spiral oil pipe is connected with the fuel oil pipe, and the tail part of the spiral oil pipe is horizontal along the axial direction; the whole length of the mixing cavity is larger than that of the central oil pipe, and the tail oil outlet is positioned at the downstream of the mixing cavity, namely the front part of the outlet of the mixing cavity.

The spiral oil pipe type three-gas path air atomizing nozzle is characterized in that: the spiral oil pipe is distributed with oil injection inclined holes with the same size, and the injected fuel oil and the inner ring main air flow have component speeds with opposite directions to force the fuel oil and the inner ring main air flow to mutually impact; the diameter of the tail part taper oil spray hole can be slightly larger than the inclined oil spray hole.

The invention has the following beneficial effects:

(1) the invention adopts the central air pipe as the inner ring auxiliary air passage, the contracted air pipe passage forces the air flow to spray out in an accelerated way, and the inner ring main and auxiliary air flow atomizes the liquid fuel in the mixing cavity, thereby greatly improving the atomization effect of the fuel compared with the traditional one-time atomization. (2) The invention adopts the spiral oil pipe, fuel oil rotates at high speed in the spiral pipe, and the fuel oil rotates at an accelerated speed along with the linear reduction of the diameter of the spiral line of the pipe. Under the combined action of centrifugal force, internal and external pressure difference and the like, fuel oil is ejected along the inclined hole of the pipe wall in a high-speed rotation mode and is impacted with the inner ring secondary air flow to generate a shearing effect, and compared with a direct injection type oil nozzle, the direct injection type oil nozzle not only thins fuel oil droplets, but also gives acceleration to the fuel oil, and meanwhile solves the problem that the fuel space is unevenly distributed. (3) The semi-spherical vortex generator is adopted, and the high-speed airflow meets the obstacle to generate a main reflux area and an auxiliary reflux area, so that the turbulence of the airflow is greatly improved, and the shearing action of oil gas is increased; in the mixing cavity, the turbulence generator can reduce the residual quantity of the fine oil drops on the wall surface, so that the fuel oil is fully atomized; the connection of the spoiler and the wall surface adopts circular arc transition, and the shell avoids the residue of fuel at the connection seam. (4) The mixed gas in the mixing cavity reaches extremely high flow velocity at the throat of the bushing, and is atomized with the outer ring cyclone for three times, so that the fuel atomization effect is enhanced.

Drawings

FIG. 1: cross-sectional view of a three-path air atomizing nozzle of the helical oil tube type

FIG. 2: side view of spiral oil pipe type three-gas path air atomizing nozzle

FIG. 3: cross-sectional views of mixing chamber and liner

FIG. 4: cross sectional view of central trachea

FIG. 5: side view of central trachea

FIG. 6: schematic diagram of spiral oil pipe

FIG. 7: side view of spiral oil pipe

In the figure: 1-mixing chamber, 2-fuel pipe, 3-coiled oil pipe, 4-central gas pipe, 5-bush, 6-oil mist spray orifice, 7-hemispherical spoiler, 8-oil spray inclined hole, 9-gas spray hole, 10-conical oil spray hole, 11-mixing chamber spray orifice (bush throat)

Detailed Description

The invention will now be further described with reference to the accompanying drawings in which:

with reference to fig. 1, the invention provides a spiral oil pipe type three-gas-path air atomizing nozzle which can effectively improve the atomizing effect of liquid fuel and solve the problem of uneven fuel space distribution.

The specific process comprises the following steps:

the gas enters from the nozzle head, one part of the gas enters the central gas pipe 4 to form inner ring secondary gas flow, and the other part of the gas enters the mixing cavity 1 to form inner ring primary gas flow; gas enters from the liner 5 to form an outer annular gas flow. The mixing cavity 1 consists of a straight section and a contraction section, the wall surface is provided with a hemispherical spoiler 7, the turbulence degree of the inner ring main airflow is increased, the rotational flow close to the wall can weaken the surface tension effect of an oil film, and the fuel oil is promoted to expand downstream along with the inner ring main airflow so as to reduce the residual quantity of the fuel oil on the wall surface. The inner ring main gas flow creates a high velocity and accompanying turbulent flow of partial recirculation within the mixing chamber 1. The inner ring secondary air flow is continuously accelerated in the contracted central air pipe 4 and reaches the maximum speed at the tail part of the pipe, the air flow is forced to be ejected out from the air injection holes 9 at high speed by the pressure difference between the inside and the outside of the pipe, the air injection holes 9 are distributed on the wall surface of the central air pipe 4 according to a spiral line, and the multi-angle injection increases the shearing action with fuel oil to a certain extent. The fuel oil enters the spiral oil pipe 3 from the fuel oil pipe 2, the fuel oil accelerates and rotates in the pipe and flows downstream under the action of centrifugal force and an energy equation, a certain distance exists between the central axis of the inclined oil injection hole 8 and the central axis of the spiral pipe at the position, and the pipe body is spiral, so that the fuel oil sprayed out of the inclined oil injection hole 8 generates circumferential component velocity; the central axis of the oil injection inclined hole 8 and the central axial included angle of the spiral pipe at the position are approximately kept at a certain angle, and the flowing direction of the main air flow of the mixing cavity is opposite to the inclined direction of the oil injection inclined hole 8, so that the injected fuel generates the axial speed along the upstream; the remaining fuel is injected from the tail cone-shaped injection hole 10 at a high speed. The fuel oil is primarily atomized into small liquid drops through the oil injection inclined holes 8, and then is collided and torn with the air flow sprayed out of the air injection holes 9 to be secondarily atomized, so that uniform rough oil mist is formed. The linear reduction of the radius of the 3 spiral lines of the spiral oil pipe, the acceleration of the inner ring airflow and the rotational flow, the turbulence and the shearing action are greatly improved, and the secondary atomization effect is enhanced. Under the blowing of the high-speed inner ring main air flow, oil mist in the air and an oil film on the wall surface of the mixing cavity 1 expand downstream and accelerate in a contraction section to flow to the throat 11 of the bushing, the throat is a narrow throat, the mixed air of the inner ring reaches the maximum flow speed, and meanwhile, the mixed air of the outer ring accelerates to flow to the throat and is crossed with the mixed air of the inner ring to form shearing impact to carry out three-time atomization. The oil mist is blown to the oil mist spray holes 6, and is better mixed in the air flow under the driving of strong turbulence formed by the three air flows of the inner ring and the outer ring, so that more uniform oil mist is formed and enters the head part of the flame tube.

Claims

1. The utility model provides a three gas circuit air atomizing nozzle of spiral oil pipe formula, has adopted three gas circuits and the atomizing scheme of cubic, its characterized in that: on the basis of the existing mixing cavity and lining structure, the outlet of the mixing cavity is set as the throat of the lining, and hemispherical disturbance fluid is distributed on the wall surfaces of the mixing cavity and the lining; an inner ring auxiliary gas path is communicated in the central gas tube and is arranged in the center of the mixing cavity, and gas injection holes with the same size are uniformly distributed on the wall surface of the gas tube; spiral oil pipe winding is in the central trachea outside, and same axis is shared to both, and the same nozzle opening of size is being distributed equally on the oil pipe wall, and the afterbody sets up the tapered oilhole that contracts.

2. The spiral oil tube type three-gas path air atomizing nozzle as set forth in claim 1, wherein: the hemispherical turbulent fluids on the straight section of the mixing cavity have the same size and are arranged in a fork arrangement mode; the contraction section is provided with the same turbulence bodies, the arrangement mode (in-line arrangement or cross arrangement) of the turbulence bodies depends on the contraction angle, and the distribution density of the turbulence bodies can be slightly smaller than that of the straight section. The joints of the turbulent flow bodies and the wall surfaces are in arc transition.

3. The spiral oil tube type three-gas path air atomizing nozzle as set forth in claim 1, wherein: the distribution of the spherical disturbing fluid on the inner wall of the lining is similar to that of the mixing cavity, the straight section is arranged in a staggered mode, the contraction section can be arranged in a staggered mode, and the distribution density can be smaller than that of the straight section.

4. The spiral oil tube type three-gas path air atomizing nozzle as set forth in claim 1, wherein: the inner diameter of the central air pipe is linearly reduced along the axial direction; the air injection holes on the tube wall have the same size and are spirally wound and distributed on the wall surface of the central air tube in equal distance and equal diameter.

5. The spiral oil tube type three-gas path air atomizing nozzle as set forth in claim 1, wherein: the external spiral diameter of the spiral oil pipe is linearly reduced, the thread pitch is constant, and the diameter of the internal pipeline is unchanged; the head part of the spiral oil pipe is connected with the fuel oil pipe, and the tail part of the spiral oil pipe is horizontal along the axial direction; the whole length of the mixing cavity is larger than that of the central oil pipe, and the tail oil outlet is positioned at the downstream of the mixing cavity, namely the front part of the outlet of the mixing cavity.

6. The spiral oil tube type three-gas path air atomizing nozzle as set forth in claim 1, wherein: the spiral oil pipe is distributed with oil injection inclined holes with the same size, and the injected fuel oil and the inner ring main air flow have component speeds with opposite directions to force the fuel oil and the inner ring main air flow to mutually impact; the diameter of the tail part taper oil spray hole can be slightly larger than the inclined oil spray hole.