Spray pipe flow control bypass with pressure stabilizing cavity

Abstract

The invention discloses a spray pipe flow control bypass with a pressure stabilizing cavity. The spray pipe flow control bypass comprises a bypass inlet, a bypass outlet and the pressure stabilizing cavity which are sequentially distributed in a spray pipe from the upstream to the downstream in the airflow flowing direction. An inner flow channel of the spray pipe comprises a spray pipe inlet, a spray pipe inner flow channel equal straight section, a spray pipe inner flow channel convergent section, a spray pipe throat, a spray pipe inner flow channel expansion section and a spray pipe outlet which are sequentially distributed in the air flow direction. The upstream of the bypass inlet is communicated with the nozzle inner flow channel equal straight section, and the downstream is communicated with the pressure stabilizing cavity; the upstream of the bypass outlet is communicated with the pressure stabilizing cavity, and the downstream is communicated with the nozzle throat or / and the nozzle inner flow channel expansion section; the pressure stabilizing cavity is used for receiving air flow from the bypass inlet, rectifying the air flow in the pressure stabilizing cavity and enabling the air flow to flow out through the bypass outlet. According to the invention, the weight caused by the wall surface of the flow control bypass is reduced, and meanwhile, the rectification of the airflow in the pressure stabilizing cavity is realized, so that the uniformity of the airflow flowing out of the pressure stabilizing cavity is better, and the airflow pulsation is smaller.

Description

Technical Field

[0001] The invention belongs to the field of advanced aircraft engine exhaust system design, and in particular relates to a nozzle flow control bypass. Background Art

[0002] With the development of science and technology and the urgent needs in practical applications, air bleed through ducts and flow control have become common specific measures in the advanced aviation field and effective means to improve performance.

[0003] In order to achieve the above goals, it has become an important measure to establish an air bleed path through a pipe with a fixed and fixed wall surface. However, the pipe with a fixed and fixed wall surface greatly affects the spatial layout of the equipment, increases the weight, and the common rigid pipe is difficult to apply to the adjustable mechanism, resulting in mutual constraints.

[0004] As far as aircraft engine nozzles are concerned, the above-mentioned air bleed ducts are extremely common and are often referred to as flow control bypasses. Common Laval nozzles can control the flow separation of the airflow on the wall of the nozzle expansion section through a flow control bypass. The dual-throat aerodynamic thrust vectoring nozzle with an adaptive bypass can adjust the thrust vector angle of the nozzle by controlling the bypass opening. There are many similar applications. Most of the above-mentioned bypasses are of fixed geometry, non-adjustable, and rigid, so they are often suitable for nozzles with fixed geometry. Once used in an adjustable nozzle, a trade-off must be made between the rigid bypass and the adjustable nozzle, which often takes up more weight, increases the complexity of the mechanism, affects the reliability of the components, and reduces the aerodynamic performance of the nozzle.

[0005] Therefore, designing a flow control bypass that is flexible, adjustable, lightweight, and has good performance is a key factor affecting whether the nozzle flow control can achieve its function. Summary of the invention

[0006] The object of the present invention is to provide a nozzle flow control bypass with a pressure stabilizing chamber to reduce the weight brought by the wall of the flow control bypass, while realizing the rectification of the airflow in the pressure stabilizing chamber, so that the airflow flowing out of the pressure stabilizing chamber is more uniform and the airflow pulsation is smaller.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A nozzle flow control bypass with a pressure stabilizing chamber comprises a bypass inlet, a bypass outlet and a pressure stabilizing chamber which are sequentially distributed along the airflow direction from upstream to downstream in the bypass of the nozzle; the inner flow channel of the nozzle comprises a nozzle inlet, a straight section of the inner flow channel of the nozzle, a convergent section of the inner flow channel of the nozzle, a nozzle throat, an expansion section of the inner flow channel of the nozzle and a nozzle outlet which are sequentially distributed along the airflow direction; the bypass inlet is connected to the straight section of the inner flow channel of the nozzle upstream and is connected to the pressure stabilizing chamber downstream; the bypass outlet is connected to the pressure stabilizing chamber upstream and is connected to the nozzle throat or / and the expansion section of the inner flow channel of the nozzle downstream; the pressure stabilizing chamber is used to receive the airflow from the bypass inlet and rectify it in the pressure stabilizing chamber before it flows out through the bypass outlet.

[0009] The number of the bypass inlet and the bypass outlet are independently one or more.

[0010] The pipeline downstream of the bypass inlet extends into the pressure stabilizing chamber, and the length of the extended portion of the pipeline in the pressure stabilizing chamber is 5%-10% of the length of the pipeline where the bypass inlet is located outside the pressure stabilizing chamber.

[0011] The pipeline upstream of the bypass outlet extends into the pressure stabilizing chamber, and the length of the extended portion of the pipeline in the pressure stabilizing chamber is not less than 20% of the length of the pipeline at the bypass inlet outside the pressure stabilizing chamber.

[0012] The pipeline inlet upstream of the bypass outlet is provided with a bell mouth.

[0013] The pressure stabilizing cavity has a changeable shape.

[0014] The boundary of the pressure stabilizing chamber is the outer wall surface, inner wall surface or internal partition plate of the nozzle, or the geometric boundary of other parts. The boundary of the pressure stabilizing chamber is rigid or flexible, and no gas penetrates or leaks from the boundary of the pressure stabilizing chamber.

[0015] The internal volume of the pressure stabilizing chamber is more than three times the internal volume of the bypass pipeline to be replaced.

[0016] Beneficial effects: The nozzle flow control bypass with a pressure stabilizing chamber provided by the present invention has the following advantages over the prior art:

[0017] (1) The concept of a broad pressure-stabilizing cavity is defined, which eliminates the fixed wall and fixed flow channel of the traditional airflow bypass, reduces the solid wall required for the airflow bypass, and a single flow control bypass is expected to reduce weight by more than 50%;

[0018] (2) The rectification of the airflow in the pressure stabilization chamber makes the airflow out of the pressure stabilization chamber more uniform and less pulsating, which helps to achieve more efficient flow control. It can be applied to the flow control of the vector generated by the aerodynamic thrust vectoring nozzle, which is expected to increase the thrust vector angle by more than 20%;

[0019] (3) By adding a pressure stabilizing cavity in the flow control bypass, the geometric, spatial, and motion constraints of the flow control bypass caused by the fixed wall and fixed geometry are reduced, making it more suitable for the flow control bypass in the adjustable nozzle;

[0020] (4) The structure is simple, which greatly simplifies the complex surface caused by the flow control bypass. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a nozzle flow control bypass with a pressure stabilizing chamber according to the present invention;

[0022] Figure 2 A schematic diagram of a flow control bypass with a pressure stabilization chamber for a Laval nozzle;

[0023] Figure 3 The schematic diagram of the flow control bypass design with a pressure stabilizing chamber for the bypass double-throat nozzle is shown;

[0024] Figure 4 A simplified schematic diagram of a nozzle flow control bypass with a pressure stabilizing chamber is shown;

[0025] Figure 5 A schematic diagram of a nozzle flow control bypass design with a pressure stabilizing chamber, a bypass inlet and multiple bypass outlets;

[0026] Figure 6 This is the Mach number cloud diagram of the numerical simulation of the typical working condition of the traditional bypass double-throat nozzle;

[0027] Figure 7 The Mach number cloud diagram of the typical numerical simulation of the bypass double-throat nozzle with a pressure stabilizing chamber flow control bypass;

[0028] In the figure: 1, nozzle inlet, 2, straight section of the flow channel in the nozzle, 3, bypass inlet, 4, pressure stabilizing chamber, 5, convergent section of the flow channel in the nozzle, 6, nozzle throat, 7, bypass outlet, 8, divergent section of the flow channel in the nozzle, 9, outer wall of the nozzle, 10, nozzle outlet. DETAILED DESCRIPTION

[0029] The present invention will be further explained below in conjunction with the accompanying drawings.

[0030] like Figures 1 to 4 As shown, a nozzle flow control bypass with a pressure stabilizing chamber of the present invention is arranged in the nozzle internal bypass, and the internal flow channel of the nozzle involved includes a nozzle inlet 1, a straight section 2 of the nozzle internal flow channel, a convergent section 5 of the nozzle internal flow channel, a nozzle throat 5, a nozzle internal flow channel expansion section 8, and a nozzle outlet 10 distributed in sequence along the airflow direction.

[0031] The nozzle flow control bypass with a pressure stabilizing chamber of the present invention comprises a bypass inlet 3, a bypass outlet 7 and a pressure stabilizing chamber 4 which are sequentially distributed from upstream to downstream along the airflow direction in the nozzle.

[0032] The bypass inlet 3 is connected to the straight section 2 of the flow channel in the nozzle upstream, and is connected to the pressure stabilizing chamber 4 downstream.

[0033] The bypass outlet 7 is connected to the pressure stabilizing chamber 4 upstream and connected to the nozzle throat 5 or the nozzle inner flow channel expansion section 8 downstream, or a plurality of bypass outlets 7 are connected to the nozzle throat 5 and the nozzle inner flow channel expansion section 8 respectively.

[0034] The pressure stabilizing chamber 4 is used to receive the airflow from the bypass inlet 3 and rectify the airflow in the pressure stabilizing chamber 4 before flowing out through the bypass outlet 7 .

[0035] The nozzle flow control bypass with a pressure stabilizing chamber of the present invention adopts a structure of a bypass inlet, a pressure stabilizing chamber, and a bypass outlet, replacing the original bypass inlet, bypass pipe, and bypass outlet structure; that is, the pressure stabilizing chamber replaces the original bypass pipe. The pressure stabilizing chamber is characterized in that it is a closed space except for the bypass inlet and the bypass outlet, and has a large internal volume with a variable volume. The pressure stabilizing chamber has a variable shape and has a certain number of airflow inlets and outlets, which reduces the weight brought by the wall of the flow control bypass, and at the same time realizes the rectification of the airflow in the pressure stabilizing chamber, so that the airflow flowing out of the pressure stabilizing chamber has better uniformity and smaller airflow pulsation.

[0036] The boundary of the pressure stabilizing chamber 4 is the outer wall surface, inner wall surface or internal partition plate of the nozzle, and its material is rigid or flexible, and there is no gas penetration or leakage from the boundary of the pressure stabilizing chamber. Thus, the geometric, spatial and motion constraints of the flow control bypass caused by the fixed wall surface and fixed geometry are reduced, and it is further suitable for the flow control bypass in the adjustable nozzle.

[0037] Compared with the replaced bypass pipe, the internal volume of the pressure stabilizing chamber is significantly larger; generally speaking, the internal volume of the pressure stabilizing chamber is more than 3 times the internal volume of the replaced bypass pipe; thereby improving the uniformity of the secondary flow out of the nozzle bypass outlet and reducing air flow pulsation.

[0038] The number of bypass inlets and bypass outlets is independently 1 or more. Generally speaking, the 1 bypass inlet-1 bypass outlet configuration is often used for simple flow control of secondary flow injection in the nozzle flow channel, which is often used to improve the secondary flow control of large expansion BiLaval nozzle flow separation, vector generation and regulation of aerodynamic thrust vectoring nozzle secondary flow control, etc. 1 bypass inlet-multiple bypass outlets are often used for a variety of application scenarios represented by nozzle wall cooling, vector generation and regulation of aerodynamic thrust vectoring nozzle secondary flow control, etc.

[0039] The pipeline downstream of the bypass inlet 3 extends into the pressure stabilizing chamber 4, and the length of the extended portion of the pipeline in the pressure stabilizing chamber 4 is 5%-10% of the length of the pipeline at the bypass inlet 3 outside the pressure stabilizing chamber 4. The pipeline upstream of the bypass outlet 7 extends into the pressure stabilizing chamber 4, and the length of the extended portion of the pipeline in the pressure stabilizing chamber 4 is not less than 20% of the length of the pipeline at the bypass inlet 3 outside the pressure stabilizing chamber 4.

[0040] The pipeline existing downstream of the bypass inlet can be completely consistent with the original bypass pipeline. The pipeline inlet upstream of the bypass outlet 7 is provided with a bell mouth to achieve the rectification of the airflow.

[0041] The present invention can be better understood with reference to the following examples.

[0042] Example 1

[0043] Figure 4 A simplified schematic diagram of a nozzle flow control bypass design with a pressure stabilization chamber is shown. All black solid lines in the figure represent the solid wall of the nozzle with a certain thickness. The pressure stabilization chamber is a bypass inlet-bypass outlet configuration. The cavities inside the nozzle throat convergence section and the nozzle expansion section together constitute the pressure stabilization chamber.

[0044] Example 2

[0045] Figure 5 The schematic diagram of a nozzle flow control bypass design with a pressure stabilizing chamber, one bypass inlet and multiple bypass outlets. It has one bypass inlet and a total of 6 bypass outlets (3 / group on each side), of which one group is used for flow control throat and the other two groups are used for cooling the nozzle wall.

[0046] Example 3

[0047] Figure 7 A nozzle flow control bypass design with a pressure stabilization chamber is presented. This solution is aimed at the bypass double-throat nozzle design. Figure 6 The adaptive bypass channel in is changed to Figure 7 Under the same nozzle working pressure drop ratio NPR=4, the improved double-throat aerodynamic thrust vectoring nozzle with adaptive bypass of the pressure stabilizing cavity of the present invention is better than the reference double-throat aerodynamic thrust vectoring nozzle ( Figure 6 ), the thrust vector angle increased from the baseline 15.93° to 20.64°, an increase of 29.6%; the thrust coefficient increased from the baseline 0.947 to 0.964, an increase of 1.2%, demonstrating the technical advantages of the present invention.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A nozzle flow control bypass with a pressure stabilizing chamber, characterized in that: The invention comprises a bypass inlet (3), a bypass outlet (7) and a pressure stabilizing chamber (4) which are sequentially distributed along the airflow direction from upstream to downstream in the bypass of the nozzle; the internal flow channel of the nozzle comprises a nozzle inlet (1), a straight section (2) of the internal flow channel of the nozzle, a convergent section (5) of the internal flow channel of the nozzle, a nozzle throat (5), an expansion section (8) of the internal flow channel of the nozzle, and a nozzle outlet (10) which are sequentially distributed along the airflow direction; the bypass inlet (3) is connected to the straight section (2) of the internal flow channel of the nozzle upstream, and is connected to the pressure stabilizing chamber (4) downstream; the bypass outlet (7) is connected to the pressure stabilizing chamber (4) upstream, and is connected to the nozzle throat (5) or / and the expansion section (8) of the internal flow channel of the nozzle downstream; the pressure stabilizing chamber (4) is used to receive the airflow from the bypass inlet (3) and rectify it in the pressure stabilizing chamber (4), and then flow out through the bypass outlet (7).

2. The nozzle flow control bypass with a pressure stabilizing chamber according to claim 1, characterized in that: The number of the bypass inlet and the bypass outlet are independently one or more.

3. The nozzle flow control bypass with a pressure stabilizing chamber according to claim 1, characterized in that: The pipeline downstream of the bypass inlet (3) extends into the pressure stabilizing chamber (4), and the length of the extended portion of the pipeline in the pressure stabilizing chamber (4) is 5%-10% of the length of the pipeline at the bypass inlet (3) outside the pressure stabilizing chamber (4).

4. The nozzle flow control bypass with a pressure stabilizing chamber according to claim 1, characterized in that: The pipeline upstream of the bypass outlet (7) extends into the pressure stabilizing chamber (4), and the length of the extended portion of the pipeline in the pressure stabilizing chamber (4) is not less than 20% of the length of the pipeline at the bypass inlet (3) outside the pressure stabilizing chamber (4).

5. The nozzle flow control bypass with a pressure stabilizing chamber according to claim 1, characterized in that: The pipeline inlet upstream of the bypass outlet (7) is provided with a bell mouth.

6. The nozzle flow control bypass with a pressure stabilizing chamber according to claim 1, characterized in that: The pressure stabilizing chamber (4) is changeable in shape.

7. The nozzle flow control bypass with a pressure stabilizing chamber according to claim 1, characterized in that: The boundary of the pressure stabilizing chamber (4) is the outer wall surface, inner wall surface or internal partition plate of the nozzle, or the geometric boundary of other parts. The boundary of the pressure stabilizing chamber (4) is rigid or flexible, and no gas penetrates or leaks from the boundary of the pressure stabilizing chamber.

8. The nozzle flow control bypass with a pressure stabilizing chamber according to claim 1, characterized in that: The internal volume of the pressure stabilizing chamber (4) is more than three times the internal volume of the bypass pipeline to be replaced.

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