CN111520750B

CN111520750B - Novel combustion chamber head oil injection structure

Info

Publication number: CN111520750B
Application number: CN202010215765.2A
Authority: CN
Inventors: 张群; 曹婷婷; 杨福正; 刘强; 李程镐; 胡凡; 李小龙; 程祥旺
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2022-05-20
Anticipated expiration: 2040-03-25
Also published as: CN111520750A

Abstract

The invention provides a novel fuel injection structure at the head of a combustion chamber, which comprises a two-stage swirler, a central cone, a flow deflector, a fuel injection ring, a fuel injection hole and other structures, wherein the structures of the swirler and the central cone increase the effective air inlet area of the swirler, increase the air flow inlet amount, and avoid the eddy loss caused by a wall surface sudden expansion structure; the air flow is divided into two paths through the flow deflector and the oil injection, the initial breaking is completed near the outlet of the oil injection hole at high speed, and the two paths of air flow with opposite rotation directions are mixed with the air, and then the two paths of air flow collide and atomize at the tail part of the oil injection ring and complete the mixing; the oil-gas mixture will be further atomized by the venturi and mixed with the secondary swirler air flow, and then the homogeneous oil-gas mixture will enter the combustion chamber for combustion.

Description

Novel combustion chamber head oil injection structure

Technical Field

The invention relates to the field of combustion chambers of aero-engines, in particular to a novel head oil injection structure of a combustion chamber.

Background

Modern aircraft engines are developed rapidly, the requirements on performance are higher and higher, and in order to meet the requirements of high performance, high thrust-weight ratio and low emission of the existing engines, various links of engine design face huge challenges. The combustor is used as the main part of gas turbine and has the main functions of pressure diffusion and speed reduction, fuel preparation, low speed region formation and return region stable flame. The combustor is designed by adopting the principle of air splitting, and an inner casing, an outer casing, a diffuser, a flame tube, a fuel nozzle and a flame stabilizing device of the combustor are indispensable components of the combustor. With the rapid development of the aircraft engine technology, the engines develop towards the high temperature and high thrust-weight ratio, and the research of the aircraft engine technology faces many technical challenges, wherein four most key technical challenges are as follows: firstly, the combustion stability is improved; secondly, the durability of the flame tube is improved; reducing pollution emission; and fourthly, reducing the temperature distribution coefficient of the outlet of the combustion chamber.

The optimized design of the combustor head structure, advanced fuel atomization and advanced combustor cooling techniques are important approaches to address the above technical challenges. The oil injection mode is a very important ring in the aspect of improving fuel atomization, and the common structure of the head of the existing combustion chamber adopts a combination form of a two-stage swirler, a direct injection type fuel nozzle and a venturi. The direct-injection fuel nozzle is easy to cause the blockage problem of the nozzle due to the small equivalent diameter, can cause obvious total pressure loss and influences the stability and reliability of the work of an engine combustion chamber, so the research on an oil injection mode and a fuel atomization effect is always an important aspect of the research on a combustion chamber head.

The jet atomization of fuel is one of the key points of the work process research of the gas turbine, the overall performance of a combustion chamber is closely related to the emission of an engine, and as an upstream boundary of fuel jet crushing and atomization, the head structure of the combustion chamber has important influence on the flow characteristic and the atomization mode of the fuel, so that the reasonable design of the head of the combustion chamber can provide a more effective control means for the atomization process and the tissue combustion of the modern gas turbine. The fuel liquid column is broken and atomized under different working conditions of the combustion chamber, the fuel injection distance is shortened, the fuel atomization effect is improved, and the mixing level of fuel and air in the combustion chamber is improved, so that the positive influence on the combustion process in the combustion chamber is achieved, and the important influence on the efficient clean utilization of energy is also achieved.

Disclosure of Invention

The invention aims to solve the technical problem of providing a novel head oil injection structure of a combustion chamber, and the effect of improving fuel atomization and stable combustion is achieved by improving the head oil injection structure.

Technical scheme

The invention aims to provide a novel combustion chamber head oil injection structure.

The technical scheme of the invention is as follows:

novel combustor head oil spout structure, its characterized in that: the novel combustion chamber head oil injection structure comprises a primary swirler, a central cone, a flow deflector, an oil injection ring, an oil injection hole, an oil delivery pipeline, a venturi tube, a secondary swirler and a sleeve.

Novel combustor head oil spout structure, its characterized in that: the burner head inlet cancels the form of matching of a nozzle and a swirler, the center of the swirler is an entity and is combined with a central cone, a wall surface sudden expansion structure is avoided, the thickness of the swirler vanes is 1.5-2 mm, and the vane installation angle is 15-25 degrees.

Novel combustor head oil spout structure, its characterized in that: the guide vane is connected oil spout ring and first order swirler internal wall, and its height is 1/6 ~ 1/8 of swirler diameter, and its blade direction of rotation is opposite with swirler blade direction of rotation, and 15 ~ 20 of blade installation angle, thickness are 2 ~ 4mm, and inside has oil pipeline, and the diameter is 1 ~ 2 mm.

Novel combustor head oil spout structure, its characterized in that: the oil injection ring is of an annular structure, the inner wall and the outer wall of the oil injection ring on the axial section are both streamlined to reduce resistance, the axial length is 1/3-1/4 of the cyclone, and the radial thickness is 15-20 mm; an oil inlet hole is formed at the joint of the outer wall and the flow deflector, and the diameter of the oil inlet hole is 1-2 mm; the inner wall surface and the outer wall surface are uniformly provided with circular inclined oil spray holes with the diameter of 1-1.5 mm, the adopted outlet is rectangular or elliptical, the oil spray holes on the inner wall surface and the axial airflow flow direction form an included angle of 25-35 degrees, and the oil spray holes on the outer wall surface and the axial airflow flow direction form an included angle of 35-45 degrees.

Novel combustor head oil spout structure, its characterized in that: defeated oil pipe diameter is 2 ~ 3mm, gets into from one-level swirler outer wall, sends into the defeated oil pipe way in the water conservancy diversion piece through one-level swirler wall with the fuel, and then stably provides the fuel for spouting the oil ring.

Novel combustor head oil spout structure, its characterized in that: the diameter of the outlet of the venturi is 7/8-6/7 of the diameter of the inlet, the contraction ratio of the venturi is 1.3-1.7, the throat of the venturi is positioned at the axial position of 1/3-1/2, the diameter of the throat of the venturi is 2/3-3/4 of the diameter of the outlet of the venturi, and the outlet expansion cone angle is 10-40 degrees.

Novel combustor head oil spout structure, its characterized in that: the secondary cyclone is a radial cyclone, the thickness of each blade is 1.5-2 mm, the installation angle of each blade is 15-25 degrees, and the expansion taper angle of the sleeve is 10-50 degrees.

The invention has the following beneficial effects:

compared with the conventional combustion chamber head structure, the novel combustion chamber head oil injection structure has the advantages that the center direct injection type nozzle is removed and changed into the small-diameter center cone, the effective air inlet area of the cyclone is increased, the air flow air inflow is increased, and the eddy loss caused by the sudden expansion structure of the wall surface is avoided; the air current is divided into two strands through the water conservancy diversion piece and fuel injection ring to accomplish near the oil spout hole export fast and break for the first time and mix with the air, then two strands of opposite rotation direction's air current collision atomizing mixes, mixes through the venturi tube and with the air current of second grade swirler, and later even oil gas mixture will get into and burn in the combustion chamber.

Drawings

FIG. 1: novel overall structure schematic diagram of head oil injection structure of combustion chamber

FIG. 2: novel internal section view of combustion chamber head oil injection structure

FIG. 3: novel combustion chamber head oil injection structure local enlarged view

In the figure: 1. the device comprises a primary cyclone, a central cone, a primary cyclone outer wall, a secondary cyclone, a secondary flow channel, a sleeve, a venturi tube, a flow deflector, a flow guide plate, a fuel injection ring, a fuel injection hole, a fuel injection pipeline and a fuel delivery pipeline, wherein the primary cyclone is 2, the central cone is 3, the primary cyclone outer wall is 4, the secondary cyclone is 5, the secondary flow channel is 6, the sleeve is 7, the venturi tube is 8, the flow deflector is 9, the fuel injection ring is 10, the fuel injection hole is 11.

Detailed Description

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

with reference to fig. 1, 2 and 3, the invention provides a technical scheme of a novel combustion chamber head oil injection structure. Fig. 1 is a schematic view of an overall structure of a novel combustion chamber head oil injection structure, fig. 2 is a sectional view of an inside of the novel combustion chamber head oil injection structure, and fig. 3 is a partial enlarged view of the novel combustion chamber head oil injection structure.

The specific process comprises the following steps: high-speed airflow from the gas compressor enters the head part of the combustion chamber from the primary swirler (1), the airflow passing through the primary swirler (1) is changed into three-dimensional high-speed rotating airflow, eddy loss generated by a simple boss structure after a nozzle is cancelled is avoided due to the existence of the small-diameter central cone (2), then the airflow is divided into an inner part and an outer part through the oil injection ring (9), the inner wall surface and the outer wall surface of the oil injection ring (9) are both streamlined, the convection flow loss is small, circular inclined oil injection holes (10) are uniformly formed in the inner wall surface and the outer wall surface, an included angle of 25-35 degrees is formed between the oil injection holes in the inner wall surface and the axial airflow flow direction, and an included angle of 35-45 degrees is formed between the oil injection holes in the outer wall surface and the axial airflow flow direction; fuel oil enters through an oil conveying pipeline (11) in the outer wall (3) of the primary cyclone, is conveyed into the oil conveying pipeline (11) in the flow guide plate through the outer wall (3) of the primary cyclone, then enters the oil injection ring (9), and is injected from oil injection holes (10) in the inner wall and the outer wall of the oil injection ring (9); the jet of the inner wall surface hole and the airflow direction are in the same direction and form an included angle, so that the primary atomization of the fuel oil is achieved, the included angle between the outer wall surface hole and the airflow is larger, part of the fuel oil collides with the wall surface or the flow deflector (8) to be crushed besides airflow crushing, and the fuel oil is rapidly crushed and atomized near the outlet in both crushing modes; then the two air flows are converged at the tail part of the oil injection ring (9), because the rotation direction of the flow deflector (8) is opposite to that of the first-stage swirler (1), the two air flows are converged at the tail part, and the fuel oil is further crushed and atomized due to the shearing action of the air flows; then the oil-gas mixture enters a venturi (7), and large-size fuel droplets in the venturi (7) can also collide and break through the wall surface to further atomize the fuel; the oil-gas mixture passing through the venturi (7) is converged with the airflow of the secondary cyclone (4), and the shearing action between the airflows further atomizes the fuel and mixes the fuel with the air, and finally the fuel enters the combustion chamber for combustion. The multi-level fuel atomization mode has better fuel atomization level, the fuel atomization at the head outlet of the combustion chamber is more uniform, the atomization distance is shortened, and the ignition reliability and the combustion stability in the combustion chamber are facilitated.

Claims

1. Novel combustor head oil spout structure, its characterized in that: the novel combustion chamber head oil injection structure comprises a primary cyclone, a central cone, a flow deflector, an oil injection ring, an oil injection hole, an oil delivery pipe, a venturi tube, a secondary cyclone and a sleeve; the airflow enters from the first-stage swirler and is divided into two parts through the flow deflector and the oil injection ring for crushing and atomizing, and because the flow deflector and the blades of the first-stage swirler rotate in opposite directions, the two airflows are sheared and atomized at the tail part of the oil injection ring, then are mixed with the airflow entering from the second-stage swirler through the venturi tube, and finally enter the combustion chamber for stable combustion.

2. The novel combustion chamber head oil injection structure as claimed in claim 1, characterized in that: the nozzle and the swirler are not used at the inlet of the head of the combustion chamber, the center of the swirler is of a central cone structure, a wall surface sudden expansion structure is avoided, the thickness of the swirler vanes is 1.5-2 mm, and the vane installation angle is 15-25 degrees.

3. The novel combustion chamber head oil injection structure as claimed in claim 1, characterized in that: the guide vane is connected oil spout ring and one-level swirler wall, and its height is 1/6 ~ 1/8 of swirler diameter, and its blade direction of rotation is opposite with one-level swirler blade direction of rotation, and 15 ~ 20 of blade installation angle, thickness are 2 ~ 4mm, and inside has oil pipeline, and the diameter is 1 ~ 2 mm.

4. The novel combustion chamber head oil injection structure as claimed in claim 1, characterized in that: the oil injection ring is of an annular structure, the inner wall and the outer wall of the oil injection ring on the axial section are both streamlined to reduce resistance, the axial length is 1/3-1/4 of the cyclone, and the radial thickness is 15-20 mm; the diameter of a hole at the joint of the outer wall and the flow deflector is 1-2 mm; circular inclined oil spray holes with the diameter of 1-1.5 mm are uniformly formed in the inner wall surface and the outer wall surface, the adopted outlet is rectangular or elliptical, the included angle between the oil spray holes in the inner wall surface and the axial airflow flowing direction is 25-35 degrees, and the included angle between the oil spray holes in the outer wall surface and the axial airflow flowing direction is 35-45 degrees.

5. The novel combustion chamber head oil injection structure as claimed in claim 1, characterized in that: defeated oil pipe diameter is 2 ~ 3mm, gets into from one-level swirler outer wall, sends into the defeated oil pipe way in the water conservancy diversion piece through one-level swirler wall with the fuel, and then stably provides the fuel for spouting the oil ring.

6. The novel combustion chamber head oil injection structure as claimed in claim 1, characterized in that: the diameter of the outlet of the venturi is 7/8-6/7 of the diameter of the inlet, the contraction ratio of the venturi is 1.3-1.7, the throat of the venturi is positioned at the axial position of 1/3-1/2, the diameter of the throat of the venturi is 2/3-3/4 of the diameter of the outlet of the venturi, and the expansion cone angle of the outlet is 10-40 degrees; the secondary cyclone is a radial cyclone, the thickness of each blade is 1.5-2 mm, the installation angle of each blade is 15-25 degrees, and the expansion taper angle of the sleeve is 10-50 degrees.