A throat-shifted aerodynamic vectoring nozzle with an asymmetric cavity design

Abstract

The present invention discloses a throat-offset aerodynamic vector nozzle with an asymmetric concave cavity design, which is characterized in that: the inner flow channel of the throat-offset aerodynamic vector nozzle includes a nozzle inlet, an equal straight section, a throat front convergent section, a throat, an asymmetric concave cavity and two throats that are sequentially connected; the asymmetric concave cavity includes a two-throat front expansion section connected to the one throat, and a two-throat front convergent section connected to the two throats; the upper part of the asymmetric concave cavity is an upper concave cavity, and the lower part of the asymmetric concave cavity is a lower concave cavity; the asymmetric design of the concave cavity is reflected in that the length of the lower concave cavity is greater than the length of the upper concave cavity; the length of the expansion section of the lower concave cavity is greater than the length of the expansion section of the upper concave cavity. Through the asymmetric design of the concave cavity, the effects of self-contained vector angle, asymmetric vector angle and radar signal shielding are obtained.

Description

Technical Field

[0001] The invention relates to the technical field of aero-engine thrust vectoring nozzles, and in particular to a throat-offset aerodynamic vectoring nozzle with an asymmetric concave cavity design. Background Art

[0002] The next generation of fighter aircraft are required to have 4S capabilities, namely super stealth, supersonic cruise, super maneuverability and super information advantage; therefore, the requirements for the aircraft exhaust system are also greatly increased, and the aircraft is required to have extremely high maneuverability, that is, the use of thrust vector exhaust system becomes an inevitable choice.

[0003] Fluid thrust vectoring nozzles have become a research hotspot in various countries due to their simple structure and light weight. Among them, the throat offset aerodynamic vectoring nozzle, as a new type of aerodynamic thrust vectoring nozzle, has the characteristics of simple overall structure and outstanding vector performance, and has received more and more attention. The traditional throat offset aerodynamic vectoring nozzle is a double throat form, and the specific structure includes nozzle inlet, straight section, a throat front convergent section, a throat, a second throat front expansion convergent section (concave cavity), and two throats.

[0004] The drag of the rear fuselage accounts for 38%-50% of the drag of the entire aircraft, of which 1 / 3 is caused by the tail nozzle and the rear fuselage. The flight-engine integration technology is the core technology of future combat aircraft after the wing-body fusion technology and the aerodynamic stealth integrated technology. Its core is the aerodynamic integration of aircraft and engine, structural integration and control integration. Among them, the exhaust system is required to be integrated with the rear fuselage to achieve better efficient internal and external flow aerodynamic characteristics and good flight performance and quality within the envelope.

[0005] There are two normal working states of the throat-shifted aerodynamic vectoring nozzle: vector state and non-vector state, and the working state is switched by whether there is airflow injection at a throat. Taking the vector state as an example, airflow is injected at the upper or lower part of a throat, and the injected airflow exerts a vertical force on the flow of the mainstream, causing disturbances in the mainstream and flowing along the wall of one side of the expansion and convergence section at the front of the second throat. The airflow deflection effect is amplified and ejected through the concave cavity, and finally generates a head-up or head-down torque. The airflow injected at a throat in the vector state can be an external air source, such as a high-pressure gas cylinder, an air pump, an external airflow of an aircraft, etc., or it can be drawn from a position inside the engine that is higher than the pressure of a throat, such as from the rear of the fan, the compressor, etc., and the gas at the turbine outlet can also be drawn through a special channel for injection to achieve adaptive passive control. Therefore, according to whether it is necessary to draw air from the outside, the throat-shifted aerodynamic vectoring nozzle is divided into active type and passive type.

[0006] However, according to current research, during the flight, due to the problem of balancing the flight torque, the aircraft often needs to have its own vector angle for the aircraft torque balance. Furthermore, aircraft such as the B2 have adopted the extension of the rear body lower edge plate to block radar signals and enhance stealth capabilities. Therefore, designing an aerodynamic vector nozzle with an asymmetric vector angle that meets the stealth requirements has become an urgent problem to be solved. Summary of the invention

[0007] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a throat-offset aerodynamic vectoring nozzle with an asymmetric concave cavity design. The asymmetric concave cavity generates an asymmetric vortex system to provide a built-in head-up / head-down vector angle for take-off / flight requirements, and generates an asymmetric head-down / head-up vector angle to address the deficiencies in the prior art.

[0008] Technical solution: To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a throat-shifted aerodynamic vectoring nozzle with an asymmetric concave cavity design, characterized in that: the inner flow channel of the throat-shifted aerodynamic vectoring nozzle includes a nozzle inlet, an equal straight section, a throat front convergent section, a throat, an asymmetric concave cavity and two throats that are sequentially connected; the nozzle is a binary configuration;

[0009] The asymmetric concave cavity includes a front expansion section of two throats connected to one throat, and a front convergence section of two throats connected to the two throats; the upper part of the asymmetric concave cavity is an upper concave cavity, and the lower part of the asymmetric concave cavity is a lower concave cavity;

[0010] The asymmetric design of the cavity is reflected in that the length of the lower cavity is greater than that of the upper cavity; the length of the expansion section of the lower cavity is greater than that of the expansion section of the upper cavity. Through this asymmetric design of the cavity, the effects of self-contained vector angle, asymmetric vector angle and radar signal shielding are obtained.

[0011] The concave cavity includes a concave cavity asymmetric angle γ, which satisfies:

[0012]

[0013] in:

[0014] L 1 is the length of the upper cavity, L 2 is the length of the lower concave cavity; d 1 is the expansion length of the upper cavity, d 2 is the expansion length of the lower concave cavity; α 1 is the expansion angle of the upper cavity, α 2 is the expansion angle of the lower concave cavity, β 1 is the convergence angle of the upper cavity, β 2 is the convergence angle of the upper cavity, D th1 is the throat length, Dth2 is the length of the second throat.

[0015] Preferably, the value range of the asymmetric angle γ of the cavity is 4° to 20°. The length of the lower cavity and the length of the upper cavity satisfy L 2 =1.02L 1 ~1.15L 1 The convergence angle β of the lower concave cavity 2 The value range is 30°~40°. The expansion angle α of the upper cavity 1 The expansion angle α of the lower concave cavity 2 The above constraints can ensure that the cavity asymmetry angle γ is within the above range and can limit the range of other undescribed parameters.

[0016] Preferably, when the throat-offset aerodynamic vector nozzle with an asymmetric concave cavity design is in a vector state, the value range of the inherent vector angle is 0° to 10°, at which time the main flow of the nozzle is deflected upward to provide a nose-up torque for the aircraft.

[0017] Beneficial effects: The asymmetric concave throat offset aerodynamic vector nozzle provided by the present invention has the following advantages over the prior art:

[0018] (1) Through the design of an asymmetric cavity, the cavity generates an asymmetric vortex system to provide a built-in nose-up / nose-down vector angle for takeoff / flight requirements and generate an asymmetric nose-down / head-up vector angle.

[0019] (2) The asymmetric cavity and rear body of the integrated design provide radar signal shielding and enhance stealth performance.

[0020] (3) The present invention can be combined with the invention of other modified throat-shifted aerodynamic vectoring nozzles and applied to other modified throat-shifted aerodynamic vectoring nozzles. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the throat-offset aerodynamic vector nozzle body structure of the present invention;

[0022] Figure 2 This is a Mach number cloud diagram of the throat-offset aerodynamic vector nozzle in a non-vector state of the present invention;

[0023] Figure 3 This is a Mach number cloud diagram of the throat-offset aerodynamic vector nozzle in the head-down vector state of the present invention;

[0024] Figure 4 This is a Mach number cloud diagram of the head-up vector state of the throat-offset aerodynamic vector nozzle of the present invention;

[0025] Figure 5This is a graph showing the variation of the vector angle of the throat-offset pneumatic vector nozzle in a non-vector state of the present invention;

[0026] Figure 6 The diagram is a regular diagram of the vector angle variation of the throat-offset aerodynamic vector nozzle of the present invention;

[0027] Figure 7 This is a thrust coefficient diagram of the throat-offset aerodynamic vector nozzle in non-vector state.

[0028] In the figure: 1-nozzle inlet, 2-straight section, 3-convergent section at the front of the first throat, 4-first throat, 5-expanding section at the front of the second throat, 6-convergent section at the front of the second throat, 7-second throat DETAILED DESCRIPTION

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

[0030] like Figure 1 As shown, it is a configuration diagram of a throat offset aerodynamic vector nozzle with an asymmetric concave cavity design. The nozzle structure includes a nozzle inlet 1, a straight section 2, a throat front convergence section 3, a throat 4, a second throat front expansion section 5, a second throat front convergence section 6, and a second throat 7. The nozzle is a binary structure. Figure 1 A side view of the nozzle.

[0031] The two throat front expansion sections 5 and the two throat front convergence sections 6 constitute the asymmetric concave cavity of the present invention.

[0032] The upper part of the cavity is the upper cavity, and the lower part of the cavity is the lower cavity. 1 is the length of the upper cavity, L 2 is the length of the lower cavity, d 1 is the length of the upper cavity expansion section, d 2 is the length of the expansion section of the lower concave cavity, α 1 is the expansion angle of the upper cavity, α 2 is the expansion angle of the concave cavity, β 1 is the upper cavity convergence angle, β 2 is the upper cavity convergence angle, D th1 is the throat length, D th2 is the length of the second throat.

[0033] The asymmetry of the cavity can further cause the asymmetry of the recirculation zone in the cavity, and further, the wave system in the cavity is also offset, so in the non-vector state, a self-contained vector angle can still be generated. In the vector state, due to the asymmetry of the cavity structure, the up / down disturbance of the throat is caused by the up / down asymmetry, which further leads to the asymmetry of the up / down separation shock waves in the cavity, and finally leads to the asymmetry of the vector angle.

[0034] The throat offset aerodynamic vector nozzle of the reference configuration has completely symmetrical upper and lower concave cavities, that is, L 1 =L 2 ,d 1 =d 2 ,α 1 =α 2 , β 1 =β 2 , the cavity-related parameters are coupled with each other.

[0035] In order to achieve the asymmetric design of the cavity, the present invention adopts the method of controlling variables for design. Compared with the symmetrical cavity, the throat area law remains unchanged, that is, D th2 =1.2D th1 , upper cavity length L 1 The expansion angle of the upper cavity is α 1 and the concave cavity expansion angle α 2 Equal, that is, α 1 =α 2 The asymmetric design of the cavity is to make L 2 >L 1 ,d 2 >d 1 ,The remaining parameters are appropriately varied according to the geometric constraints and ,design requirements.

[0036] Define the cavity asymmetry angle γ equal to

[0037]

[0038] The range of the cavity asymmetric angle γ is 4° to 20°. Under the premise of ensuring the angle, the length of the lower cavity is greater than the length of the upper cavity, that is, L 2 >L 1 , and the range is L 2 =1.02L 1 ~1.15L 1 . Convergence angle of the lower concave cavity β 2 The range is 30°~40°. The above constraints can ensure that the cavity asymmetric angle γ is within the above range, and can limit the range of other undescribed parameters. Through the design of the above geometric parameters, when the nozzle is in a non-vector state, the range of the self-contained vector angle is 0~10°. When the nozzle is in a vector state, the head-up / head-down vector angle is asymmetric, and the difference range is 3~16°. Through the asymmetric design of the cavity, the effect of obtaining an asymmetric vector angle and shielding the radar signal can be achieved.

[0039] Here we introduce the spanwise depth Lz commonly used in the art, that is, the depth of the nozzle along the spanwise extension. Lz is the same for the entire nozzle. Throat area = Lz*D th , when Lz is determined, by changing the corresponding throat length D th To control the corresponding throat area, so Dth It can also be seen as a symbol indicating the relationship between the corresponding throat areas.

[0040] Figure 2 , 3 Figure 4 shows the Mach number cloud diagrams of the three states of a throat-shifted aerodynamic vectoring nozzle with a typical asymmetric cavity design. It can be seen that in the non-vector state, the nozzle has a self-contained vector angle, the head-down vector is not equal to the head-up vector, and the head-up vector is significantly larger than the head-down vector. The asymmetry of the cavity can further cause the asymmetry of the recirculation zone in the cavity, and further, the wave system in the cavity is also shifted, so in the non-vector state, a self-contained vector angle can still be generated. In the vector state, due to the asymmetry of the cavity structure, the up / down asymmetry is generated when the throat is disturbed, which further leads to the asymmetry of the up / down separation shock waves in the cavity, and finally leads to the asymmetry of the vector angle.

[0041] Figure 5 , 6 , 7 show the performance parameters of a typical asymmetric cavity design throat offset aerodynamic vectoring nozzle. It can be seen that the self-contained vector angle can reach about 9°. In the vector state, the thrust vector angle is asymmetric. Compared with the basic configuration, the asymmetric cavity configuration can increase both the head-down and head-up vector angles. In the non-vector state, the thrust coefficient can also be slightly improved compared with the basic configuration. (EXAMPLE 1, 2, and 3 are three typical asymmetric cavity throat offset aerodynamic vectoring nozzles based on the design criteria of this patent).

[0042] 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 throat-shifted aerodynamic vectoring nozzle with an asymmetric concave cavity design. Features: The inner flow passage of the throat-shifted aerodynamic vectoring nozzle comprises a nozzle inlet (1), a straight section (2), a throat front convergent section (3), a throat (4), an asymmetric cavity and two throats (7) which are connected in sequence. The throat-shifted aerodynamic vectoring nozzle is a binary configuration. The asymmetric concave cavity comprises a second throat front expansion section (5) connected to a throat (4), and a second throat front convergence section (6) connected to the second throat (7); the upper part of the asymmetric concave cavity is an upper concave cavity, and the lower part of the asymmetric concave cavity is a lower concave cavity; the length of the lower concave cavity is greater than the length of the upper concave cavity; the length of the expansion section of the lower concave cavity is greater than the length of the expansion section of the upper concave cavity; The concave cavity includes a concave cavity asymmetric angle γ, which satisfies: in: L 1 is the length of the upper cavity, L 2 is the length of the lower concave cavity; d 1 is the expansion length of the upper cavity, d 2 is the expansion length of the lower concave cavity; α 1 is the expansion angle of the upper cavity, α 2 is the expansion angle of the lower concave cavity, β 1 is the convergence angle of the upper cavity, β 2 is the convergence angle of the upper cavity, D th1 is the throat length, D th2 is the length of the second throat.

2. The throat-shifted aerodynamic vectoring nozzle with an asymmetric concave cavity design as claimed in claim 1, Features: The value range of the cavity asymmetric angle γ is 4°~20°.

3. The throat-shifted aerodynamic vectoring nozzle with an asymmetric concave cavity design as claimed in claim 1, Features: The length of the lower cavity and the length of the upper cavity satisfy L 2 =1.02L 1 ~1.15L 1 .

4. The throat-shifted aerodynamic vectoring nozzle with an asymmetric concave cavity design as claimed in claim 1, Features: The convergence angle β of the lower concave cavity 2 The value range is 30°~40°.

5. The throat-shifted aerodynamic vectoring nozzle with an asymmetric cavity design as claimed in claim 2, Features: The expansion angle α of the upper concave cavity 1 The expansion angle α of the lower concave cavity 2 equal.

6. The throat-shifted aerodynamic vectoring nozzle with an asymmetric cavity design as claimed in claim 1, Features: When the throat-offset aerodynamic vectoring nozzle with an asymmetric concave cavity design is in a vector state, the value range of the self-contained vector angle is 0°~10°.

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