CN111520757B - Direct injection type concave cavity swirl nozzle - Google Patents

Abstract

The invention provides a direct injection type concave cavity swirl nozzle, which comprises structures such as an oil inlet, an oil delivery pipe, an annular cavity, a concave cavity, an oil injection hole and the like, and has the advantages that: compare the head with conventional direct injection formula nozzle and have the cavity structure, the defeated oil pipe fuel of inside center is direct by the blowout of central nozzle opening, and the defeated oil pipe of two sides carries the fuel to get into the ring chamber, spout by four rows of crisscross nozzle openings of arranging (direct injection nozzle opening and radial nozzle opening) again, can form the weak whirl of minizone in the cavity, the fuel is broken with higher speed, shortens the fuel atomization distance, improves the fuel atomization quality, even fuel distributes also can effectual reduction pollutant and discharges.

Description

Direct type concave cavity swirl nozzle

technical field

The present invention relates to the field of aero-engine combustion chambers, in particular to a direct-shot concave cavity swirl nozzle.

Background technique

With the continuous development of the aviation industry, higher requirements are put forward for the performance of aero-engines. Modern aero-engines are developing in the direction of high performance, high thrust-to-weight ratio, low emissions and economy. In order to meet the current requirements for engines, in the engine design All aspects of the process are facing enormous challenges. Among them, the combustion chamber is the main power supply structure of the aero-engine, and its main functions are to diffuse pressure and reduce speed, prepare fuel, and form a low-speed area or a recirculation area to stabilize the flame. The performance of the combustion chamber directly affects various indicators such as engine thrust and emissions. Therefore, the design of the combustion chamber is particularly important. The modern aero-engine combustion chamber mainly adopts the principle of air split. The main components of the combustion chamber structure include the outer casing, diffuser, flame tube, fuel nozzle and flame stabilization device. The combustion chamber has achieved stable combustion and low pollutant emissions. , high durability and uniform outlet temperature distribution coefficient requirements.

One of the key technologies for the combustion chamber to affect the emission is the fuel injection method of the combustion chamber head. The advanced fuel atomization method can well solve the combustion stability and low emission performance requirements of the combustion chamber. At present, the common structure of the combustion chamber head is It adopts a combination of two-stage swirler, direct injection fuel nozzle and venturi. The high-speed airflow from the compressor is mixed with the fuel oil through the swirler to provide the combustion chamber with a suitable oil-fuel ratio for combustion, and generates a stable flame in the recirculation zone near the head outlet; and the direct-injection fuel nozzle that is often used at present, due to etc. The small effective diameter can easily lead to the blockage of the nozzle, which will cause obvious total pressure loss and affect the stability and reliability of the combustion chamber of the engine. important aspects of research.

Jet atomization of fuel has always been one of the research focuses of the combustion process of aero-engines. The atomization level and blending level of fuel are closely related to the combustion performance and emission indicators of the combustion chamber. As the upstream boundary of fuel jet fragmentation and atomization, combustion The design of the chamber head is particularly critical, which directly affects the fuel flow characteristics and the atomization mode. Therefore, rational optimization of the main component that supplies fuel to the combustion chamber, that is, the nozzle is the most direct means to improve fuel atomization, so that the combustion chamber can stabilize the fuel supply even under different working conditions, shorten the fuel injection distance, and improve the fuel atomization. It not only has a positive impact on the combustion process in the combustion chamber, but also has an important impact on the efficient and clean utilization of energy.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to propose a direct-shot concave-cavity swirl nozzle, which can improve fuel atomization level, stabilize combustion and reduce pollutant emissions by improving the direct-shot nozzle at the head of the combustion chamber.

Technical solutions

The purpose of the present invention is to provide a direct-shot concave cavity swirl nozzle, which can improve the level of fuel atomization, stabilize combustion and reduce pollutant emissions.

The technical scheme of the present invention is as follows:

The direct injection concave cavity swirl nozzle is characterized in that: the direct injection concave cavity swirl nozzle includes an oil inlet hole, a side oil pipeline, a central oil pipeline, an annular cavity, a radial oil injection hole, a direct injection oil injection hole, a concave cavity, a Stage radial injection hole, secondary radial injection hole, central injection hole.

The direct-shot concave cavity swirl nozzle is characterized in that: the outer diameter of the direct-shot concave cavity swirl nozzle is 20-25mm, the outer wall of the head is streamlined, and the depth of the concave cavity structure at the outlet is equal to 1/6 of the full length. ; The fuel sprayed from the radial injection holes drives the fuel sprayed from the direct injection holes to form a weak swirl in the cavity, which accelerates the fragmentation and atomization of the fuel and shortens the fuel injection distance.

The direct-shot concave cavity swirl nozzle is characterized in that: the oil pipeline is divided into two side oil pipelines and a central oil pipeline, which enters through the oil inlet hole, and is divided into three strands at 1/3 of the total length based on the oil inlet end. The diameter of the central fuel pipe is 2-3mm, and the fuel is directly sprayed from the central fuel injection hole. The diameter of the side fuel pipe is 5-7mm, and the fuel enters the annular cavity to provide fuel for the multi-stage fuel injection holes of the head.

The direct injection concave cavity swirl nozzle is characterized in that: there are two rows of direct injection oil injection holes, the diameter of which is 1-2 mm, which is arranged in a ring; The radial injection hole of the first stage is 2-3mm in diameter and the angle between the tangential angle of the circumference is 50°-60°, and the diameter of the radial injection hole of the second stage is 3-4mm and the tangential angle of the circumference is 75°. -90°.

The direct-shot concave cavity swirl nozzle is characterized in that: taking the oil inlet end as the benchmark, it enters the annular cavity at a distance of 3/4 of the full length from the inlet, and the annular cavity wall thickness is 2-3 mm.

The present invention has the following beneficial effects:

The advantages of the direct injection concave cavity swirl nozzle of the present invention are mainly manifested in that, compared with the conventional direct injection nozzle, the head concave cavity structure, two side fuel pipes transport fuel into the annular cavity, and then four rows of staggered fuel injection holes ( Direct injection holes and radial injection holes) can form a small range of weak swirl in the cavity, accelerate fuel fragmentation, shorten fuel atomization distance, improve fuel atomization quality, and even fuel distribution can also be effective. Reduce pollutant emissions.

Description of drawings

Figure 1: Schematic diagram of the overall structure of the direct-shot concave cavity swirl nozzle

Figure 2: Cross-sectional view of the central axis of the direct-shot concave cavity swirl nozzle

Figure 3: Cross-sectional view of the radial injection hole in the head of the direct-shot concave swirl nozzle

In the picture: 1. Oil inlet hole, 2. Side oil pipe, 3. Central oil pipe, 4. Annular cavity, 5. Radial injection hole, 6. Direct injection hole, 7. Concave cavity, 8. Level 1 radial Oil injection hole, 9. Secondary radial oil injection hole, 10. Central oil injection hole, L is the total length of the direct-shot concave cavity swirl nozzle.

Detailed ways

Now in conjunction with the accompanying drawings, the present invention will be further described:

1, 2, and 3, the present invention provides a technical solution for a direct-shot concave cavity swirl nozzle. Figure 1 is a schematic diagram of the overall structure of the direct-shot concave cavity swirl nozzle, Figure 2 is a cross-sectional view of the central axis of the direct-shot concave cavity swirl nozzle, and Figure 3 is a direct-shot concave cavity swirl nozzle. A cross-sectional view of the head radial injection hole.

Specific process: the fuel enters the nozzle through the oil inlet hole (1), and is divided into a side fuel pipe (2) and a central fuel pipe (3) at 1/3 of the total length. ), the side fuel pipe (2) sends the fuel into the annular cavity (4) to supply fuel to the multi-stage fuel injection holes, and the fuel sprayed from the radial fuel injection holes (5) will form a swirl in the cavity (7). The structure, the staggered distribution with the direct injection holes (6) can drive the direct injection to form a swirl together, and weaken the effect of the swirl, so that the fuel can still be ejected at a relatively concentrated spray cone angle when it is sprayed out of the nozzle. The fuel can be broken and atomized to a certain extent before it is sprayed; the fuel injected from the radial injection holes (5) and the direct injection holes (6) in the cavity (7) collides to cause a large area of the fuel to be broken, while the cavity ( 7) The weak swirling flow generated in the interior uses the shearing action of the airflow to further break up and atomize the fuel. After that, the fuel enters the combustion chamber through the head outlet and is mixed with the high-speed rotating airflow from the swirler into the combustion chamber for combustion.

Claims (5)

1. Direct-injection type concave cavity swirl nozzle, its characterized in that: the direct injection type cavity swirl nozzle comprises an oil inlet hole, a side oil delivery pipe, a center oil delivery pipe, an annular cavity, a radial oil injection hole, a direct injection oil injection hole, a cavity and a center oil injection hole, wherein the direct injection oil injection hole and the radial oil injection hole are annularly distributed in the cavity along the circumferential direction, and four rows of oil injection holes are formed by arranging the single-row direct injection oil injection hole and the single-row radial oil injection hole at intervals.

2. The direct cavity swirl nozzle of claim 1, wherein: the outer diameter of the direct-injection type concave cavity swirl nozzle is 20-25mm, the outer wall of the head part is streamline, and the outlet is 1/6 with the depth of a concave cavity structure equal to the full length; the fuel oil sprayed from the radial fuel spray holes drives the fuel oil sprayed from the direct fuel spray holes to form weak rotational flow in the concave cavity, so that the crushing and atomization of the fuel oil are accelerated, and the fuel oil spraying distance is shortened.

3. The direct cavity swirl nozzle of claim 1, wherein: the oil delivery pipe is divided into two side oil delivery pipes and a central oil delivery pipe, the side oil delivery pipes enter from oil inlet holes, the side oil delivery pipes are divided into three parts at the position of the full length 1/3 by taking an oil inlet end as a reference, the diameter of the central oil delivery pipe is 2-3mm, fuel oil is sprayed out from the central oil injection hole, the diameter of the side oil delivery pipes is 5-7mm, and the fuel oil enters into an annular cavity to provide fuel oil for the head multistage oil injection hole.

4. The direct cavity swirl nozzle of claim 1, wherein: two rows of direct injection oil injection holes with the aperture of 1-2mm are annularly arranged; the radial oil spray holes are divided into a first-stage radial oil spray hole and a second-stage radial oil spray hole, the included angle between the diameter of the first-stage radial oil spray hole and the circumferential tangent is 50-60 degrees, and the included angle between the diameter of the second-stage radial oil spray hole is 3-4mm and the circumferential tangent is 75-90 degrees.

5. The direct cavity swirl nozzle of claim 1, wherein: the oil inlet end is taken as a reference, the oil enters the annular cavity at the position which is far away from the inlet 3/4 and the wall thickness of the annular cavity is 2-3 mm.

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