Aerodynamic vectoring nozzle utilizing adaptive wave train to change flow direction

Abstract

The application discloses a kind of aerodynamic vectoring nozzle for changing flow direction by adaptive wave train, and the internal flow passage is mainly composed of upper wall surface, lower wall surface and inner plug cone.The inner plug cone separates the internal flow passage of nozzle into upper and lower two passages.The upper wall surface, lower wall surface and inner plug cone are provided with mechanical adjusting mechanism, which can independently or linkage adjust the throat area and outlet area of the upper and lower two passages, so as to independently adjust the sum of the throat area of the upper and lower two passages and the area ratio of each other, use the adaptive wave train formed by the pressure difference at the intersection of the upper and lower two passages to change the flow direction of the two passages, and achieve the purpose of changing the thrust vector angle and pitching moment of the nozzle.The airflow direction angle of the application is determined by the area ratio of the upper and lower two passages, and is less affected by the pressure ratio, and the vector angle is almost the same under high pressure ratio (>20) and low pressure ratio (<10).Meanwhile, the throat area can be adjusted to meet the flow demand under different working conditions of the engine.

Description

Technical Field

[0001] This invention relates to the field of aero-engine vector nozzle technology, specifically to an aerodynamic vector nozzle that uses an adaptive wave system to change the flow direction. Background Technology

[0002] Aircraft equipped with thrust vectoring can achieve attitude control through the direct control torque generated by thrust, gaining better agility, post-stall maneuverability, and superior flight qualities, thus gaining an advantage in air combat. The vectoring nozzle is the core component of thrust vectoring control, determining the technological level of the aircraft and engine, and is one of the key technologies for future fighter jets. Existing mechanical vectoring nozzles include: mechanical-hydraulic linkage type, deflector type, and gas-rudder type; they are structurally complex, weighing approximately 30% of the total engine weight and costing up to 40% of the total engine value, with poor maintainability and reliability. Therefore, developing a vectoring nozzle with a simple structure, light weight, and good maintainability is urgently needed.

[0003] Currently, aerodynamic vectoring nozzles are gradually becoming a research focus and hot topic in various countries due to their simple structure, light weight, and small radar cross-section, and they have important application prospects in aircraft engines. Current research on aerodynamic vectoring nozzles mainly includes throat deflection and co-current / counter-current types, most of which suffer from problems such as difficulty in flow control, low thrust coefficient, and increased drag due to complex external shapes, thus posing challenges for engineering applications.

[0004] Therefore, this invention proposes an aerodynamic vector nozzle that uses an adaptive wave system to change the flow direction. By adjusting the geometry of the upper and lower walls and the inner cone, the area ratio of the upper and lower flow channels is changed, thereby changing the degree of expansion of the airflow in the upper and lower flow channels. The adaptive wave system generated by the pressure difference of the airflow at the intersection of the upper and lower flow channels is used to change the airflow direction, thereby achieving the purpose of changing the nozzle thrust vector angle and pitching moment. Summary of the Invention

[0005] Purpose of the invention: This invention proposes an aerodynamic vector nozzle that uses an adaptive wave system to change the flow direction. By adjusting the geometry of the upper and lower walls and the inner cone, the area ratio of the upper and lower flow channels is changed, thereby changing the degree of expansion of the airflow in the upper and lower flow channels. The adaptive wave system generated by the pressure difference of the airflow at the confluence of the upper and lower flow channels is used to change the airflow direction, thereby achieving the purpose of changing the nozzle thrust vector angle and pitching moment.

[0006] Because the throat areas of both the upper and lower flow channels can be adjusted, the flow rate adjustment requirements can be met simultaneously with vector adjustment. Utilizing the principle of adaptive wave systems, the airflow direction angle is determined by the ratio of the upper and lower flow channel areas. Therefore, the nozzle vector angle is less affected by the pressure drop ratio, and the vector angles for high pressure drop ratios (>20) and low pressure drop ratios (<10) are almost identical.

[0007] Technical solution:

[0008] An aerodynamic vector nozzle that uses an adaptive wave system to change the flow direction includes an upper wall, a lower wall, and an adjustable inner plug cone; the adjustable inner plug cone divides the inner flow channel of the binary vector nozzle into upper and lower flow channels; the upper wall and the lower wall form the nozzle inlet and nozzle outlet; the adjustable inner plug cone and the upper wall form the upper flow channel throat and upper flow channel outlet; the adjustable inner plug cone and the lower wall form the lower flow channel throat and lower flow channel outlet.

[0009] Preferably, the converging and expanding sections of the upper and lower walls are each driven and connected to a first mechanical adjustment mechanism, which adjusts the length of the converging and expanding sections. The first mechanical adjustment mechanism is a hydraulically or electrically driven telescopic linkage mechanism. The adjustable inner plug cone is driven and connected to a second mechanical adjustment mechanism, which adjusts the four wall sections of the adjustable inner plug cone. The second mechanical adjustment mechanism includes four hydraulically or electrically driven telescopic linkage mechanisms, which are respectively driven and connected to the four wall sections. By changing the position and shape of the upper wall, lower wall, and adjustable inner plug cone, the areas of the upper flow channel throat, lower flow channel throat, upper flow channel outlet, and lower flow channel outlet can be adjusted independently or in conjunction.

[0010] Beneficial effects: The aerodynamic vector nozzle that utilizes an adaptive wave system to change the flow direction provided by this invention has the following advantages compared to existing technologies:

[0011] 1) By generating a slanted shock wave system through pressure balance, a thrust vector is induced to meet the requirements of high pressure ratio propulsion systems;

[0012] 2) The thrust vector is generated through pressure balance, which has a high thrust coefficient and is not sensitive to flow rate and external environment; and the nozzle has a smooth outer surface and low bottom drag.

[0013] 3) By changing the inner cone, flow regulation and vector generation were achieved, meeting the needs of future high-speed aircraft. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the adaptive wave system principle utilized in this invention.

[0015] Figure 2(a) is a schematic diagram of the aerodynamic vector nozzle configuration that uses an adaptive wave system to change the flow direction according to the present invention.

[0016] Figure 2(b) is a schematic diagram of the first mechanical adjustment mechanism and the second mechanical adjustment mechanism described in this invention;

[0017] Figure 2(c) is a side view of the first and second mechanical adjustment mechanisms described in this invention;

[0018] Figure 3 This is a schematic diagram of the flow field structure of the aerodynamic vector nozzle that uses an adaptive wave system to change the flow direction, as described in this invention.

[0019] Figure 4 This is a typical Mach number cloud diagram of an aerodynamic vector nozzle that uses an adaptive wave system to change the flow direction, as described in this invention.

[0020] Figure 5 This is a numerical schlieren image of a typical aerodynamic vector nozzle that uses an adaptive wave system to change the flow direction, as described in this invention.

[0021] Figure 6 This is a typical airflow angle contour map of an aerodynamic vector nozzle that uses an adaptive wave system to change the flow direction, as described in this invention.

[0022] Figure 7 This is a dimensionless wall pressure distribution diagram of a typical aerodynamic vector nozzle that uses an adaptive wave system to change the flow direction, as described in this invention.

[0023] Figure 8 This is a typical outlet airflow angle distribution diagram of an aerodynamic vector nozzle that utilizes an adaptive wave system to change the flow direction, as described in this invention.

[0024] Figure 9 These are shock wave-expansion wave polarograms at the nozzle exit with different area ratios.

[0025] In the figure: upper wall (1), lower wall (2), nozzle inlet (3), adjustable inner plug cone (4), upper flow throat (5), lower flow throat (6), upper flow outlet (7), lower flow outlet (8), nozzle outlet (9). Detailed Implementation

[0026] The invention will now be further explained with reference to the accompanying drawings.

[0027] Figure 1 This is a schematic diagram of the adaptive wave system principle utilized in this invention. When two supersonic airflows with different pressures converge, they achieve pressure balance through shock waves or expansion waves, while simultaneously changing their flow direction. Depending on the initial direction angle and pressure magnitude of the two airflows at the time of convergence, two scenarios can occur: both airflows achieve pressure balance through oblique shock waves, and one airflow achieves pressure balance through a shock wave while the other achieves pressure balance through an expansion wave. The critical scenario is that one airflow achieves pressure balance through a shock wave while the other does not. This flow phenomenon is simply referred to as an adaptive wave system.

[0028] Figure 2 is a schematic diagram of the aerodynamic vector nozzle configuration that utilizes an adaptive wave system to change the flow direction according to the present invention. The schematic diagram in Figure 2 includes an upper wall (1), a lower wall (2), a nozzle inlet (3), an adjustable inner plug cone (4), an upper flow throat (5), a lower flow throat (6), an upper flow outlet (7), a lower flow outlet (8), and a nozzle outlet (9). Figure 3 The diagram shows a flow field structure in which one flow path passes through a shock wave and another flow path passes through an expansion wave to achieve pressure balance.

[0029] To further illustrate the principle of this invention, a typical nozzle utilizing an adaptive wave system was designed and inviscid numerical simulations were performed. The upper channel area ratio of this nozzle is 2, the lower channel area ratio is 3, and the total area ratio is 2.4. Figure 4 , 5 Figures 6 and 6 respectively present the Mach number contour plot, numerical schlieren plot, and airflow angle contour plot. Through... Figure 4 As can be seen from the Mach number cloud map, there is a significant difference in the degree of airflow expansion between the upper and lower channels. The lower channel has a greater degree of expansion and a higher Mach number. According to the basic principles of fluid mechanics, the pressure in the lower channel is lower. Figure 5 The numerical schlieren plot reflects the density gradient of the airflow along the X-axis, with density gradients greater than 0 shown in red and density gradients less than 0 shown in blue. The plot shows that at the confluence of the two airflows, the upper flow channel achieves density equilibrium through an expansion wave, while the lower flow channel achieves equilibrium through an oblique shock wave. According to basic principles of fluid mechanics, pressure equilibrium is also achieved. Figure 6 An airflow angle contour map is provided, showing that the airflow direction angle changes significantly at the point where the upper and lower airflows meet.

[0030] To verify the feasibility of designing aerodynamic vectors using the principle of changing airflow direction with an adaptive wave system, the wall pressure distribution and outlet airflow angle distribution of the above-mentioned nozzle were statistically analyzed, as shown below. Figure 7 , 8 As shown, it is evident that the nozzle outlet (9) must be located downstream of the upper flow channel outlet (7) and the lower flow channel outlet (8) during the design process. This is to fully utilize the pressure difference between the upper and lower walls and to maximize the portion of the airflow direction angle change at the nozzle outlet, thereby increasing the vector angle.

[0031] To explore the limits of generating aerodynamic vectors using the principle of changing airflow direction using adaptive wave systems, the following is given: Figure 9Shock-expansion wave polarimetric curves of nozzle exit airflow with different area ratios. The abscissa of the intersection point of the curves with different area ratios represents the flow direction angle after the airflow converges. It can be seen that airflow angles from 0° to at least 20° can be easily achieved by combining different area ratios. Furthermore, since this invention utilizes an adaptive shock-expansion wave system, the airflow angle is only affected by the area ratio of the two flow channels and is not affected by the nozzle pressure drop. When adjusting this invention, the thrust vector effect can be achieved even at higher pressure drops by adjusting the ratio.

[0032] The upper wall, lower wall, and adjustable inner plug cone undergo forward and backward translation, up and down translation, rotation around the axis, and deformation to independently or in conjunction with the areas of the upper and lower flow channel throats, the upper and lower flow channel outlets, and the lower flow channel outlet. Ultimately, this allows for independent adjustment of the sum of the areas of the upper and lower flow channel throats and their respective area ratios, thereby controlling the nozzle flow rate and generating the required vector angle.

Claims

1. A pneumatic vector nozzle that utilizes an adaptive wave system to change the flow direction, characterized in that, It includes an upper wall (1), a lower wall (2), and an adjustable inner plug cone (4); both the upper wall (1) and the lower wall (2) include a convergent section and a diverging section, and the adjustable inner plug cone (4) divides the inner flow channel of the binary vector nozzle into upper and lower flow channels; the upper wall (1) and the lower wall (2) form the nozzle inlet (3) and the nozzle outlet (9); the adjustable inner plug cone (4) and the upper wall (1) form the upper flow channel throat (5) and the upper flow channel outlet (7); the adjustable inner plug cone (4) and the lower wall (2) form the lower flow channel throat (6) and the lower flow channel outlet (8); By adjusting the geometry of the upper and lower walls and the inner cone, the area ratio of the upper and lower flow channels is changed, thereby altering the degree of airflow expansion in the upper and lower flow channels. The pressure difference between the upper and lower flow channels at their intersection generates an adaptive wave system to change the airflow direction, thus achieving the purpose of changing the nozzle thrust vector angle and pitching moment.

2. The aerodynamic vector nozzle for changing the flow direction using an adaptive wave system according to claim 1, characterized in that, The converging and expanding sections of the upper wall (1) and lower wall (2) are all driven and connected to a first mechanical adjustment mechanism. The length of the converging and expanding sections is adjusted by the first mechanical adjustment mechanism. The first mechanical adjustment mechanism adopts a hydraulic or electric driven telescopic linkage mechanism. The adjustable inner plug cone (4) is driven and connected to a second mechanical adjustment mechanism. The four wall sections of the adjustable inner plug cone are adjusted by the second mechanical adjustment mechanism. The second mechanical adjustment mechanism includes four hydraulic or electric driven telescopic linkage mechanisms, which are respectively driven and connected to the four wall sections. By changing the position and shape of the upper wall (1), lower wall (2) and adjustable inner plug cone (4), the areas of the upper flow channel throat (5), lower flow channel throat (6), upper flow channel outlet (7) and lower flow channel outlet (8) are adjusted in a coordinated manner.

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