Passive fluid thrust vectoring nozzle and method for controlling linearity by regulating force vector angle

Abstract

The invention discloses a method for rapidly regulating and controlling the force vector angle control linearity of a passive fluid thrust vectoring nozzle. The passive fluid thrust vectoring nozzle comprises a main jet flow channel, a secondary flow control valve, a secondary flow injection channel, a wedge-shaped Coanda wall face and a secondary flow injection hole. The main jet flow channel is located between the secondary flow injection channels, and secondary flow is sucked in through the secondary flow injection holes. The secondary flow control valve is installed on the outer side of the secondary flow injection channel, and the suction flow of the main jet flow to the secondary flow is controlled by changing the opening area. According to the method for rapidly regulating and controlling the force vector angle control linearity of the passive fluid thrust vectoring nozzle, the problem that the force vector angle control linearity of a geometrically fixed nozzle cannot be regulated and controlled in the early stage is effectively solved, and the capability that the nozzle meets the engine control requirement under different geometric configurations and jet flow speeds is achieved; and the engineering practicability of the passive fluid thrust vectoring nozzle on an aircraft is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft thrust vectoring, and particularly relates to a passive fluid thrust vector nozzle and a method for regulating the linearity of the control of the force vector angle. Background Technique

[0002] Thrust vectoring technology is of great significance for enhancing the flight control stability, stealth performance, agility, etc. of aircraft, and is a key technology for the development of future high-performance aircraft. Currently, most high-performance aircraft in the world adopt mechanical or active fluid thrust vectoring technology, which has the disadvantages of slow deflection response, complex structure and large weight, and the need for additional air sources or bleeding air from the engine. Based on this, a new passive fluid thrust vector technology based on jet entrainment effect has been developed. This technology controls the degree of self-entrainment of the jet on the surrounding fluid, generates a pressure difference on both sides of the jet to drive the jet to deflect, and does not require a secondary air source and too many mechanical components. Therefore, it has the advantages of few moving parts, light structural weight, and fast deflection response, and has broad application prospects on aircraft.

[0003] Early research found that most of the passive fluid thrust vector nozzles with rectangular configurations have problems such as sudden jumps, hysteresis, and non-linearity in the control of the force vector angle. Through a large number of wind tunnel tests and CFD numerical simulations, relevant researchers have preliminarily obtained the influence laws of key nozzle geometric configuration parameters such as plate length, inclination angle, and position difference on the force vector angle control characteristics. On this basis, the researchers further designed a nozzle with a wedge configuration with a certain included angle at the trailing edge. Although experiments have proved that the wedge nozzle can solve the problems of sudden jumps and hysteresis in the control of the force vector angle of the rectangular nozzle, changing the jet velocity and the size of the trailing edge included angle will significantly change the linearity of the force vector angle control of the nozzle. Moreover, using the traditional differential control method of secondary flow valves with an unadjustable initial position, it is impossible to regulate the linearity of the force vector angle control of geometrically fixed nozzles, and it is difficult to make the nozzle work at the design point that meets the engine control requirements under different geometric configurations and jet velocities. The above discussion shows that the common method to improve the control linearity of the nozzle at present is to carry out the configuration design of the nozzle, but relevant research shows that there is a large coupling effect between the geometric configuration and the linearity of the force vector angle control of the nozzle. Therefore, the research period for improving the linearity of the force vector angle control by designing the nozzle configuration is long and the difficulty is high, and it is difficult to match different engine operating conditions only through configuration design, and it is impossible to break through the engineering practical bottleneck of shortening the nozzle development period and realizing reliable control on aircraft. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a passive fluid thrust vector nozzle and a method for regulating the linearity of the force vector angle control. Without changing the geometric configuration parameters of the nozzle, the nozzle and the method only use the differential starting point of the bilateral secondary flow control valve to control the initial actuation position of the differential regulation valve, and have the ability to adapt to different nozzle geometric configurations and jet velocities, and quickly regulate the linearity of the nozzle force vector angle control, which can provide a solution for the nozzle to adapt to all working conditions on the aircraft and reliable control.

[0005] To achieve the above invention purpose, the present invention adopts the following technical solutions:

[0006] A passive fluid thrust vector nozzle includes a main jet flow channel, a secondary flow control valve, a secondary flow injection channel, a wedge-shaped Coanda wall surface, and a secondary flow injection hole. The secondary flow control valve includes an upper secondary flow control valve and a lower secondary flow control valve. The secondary flow injection channel includes an upper secondary flow injection channel and a lower secondary flow injection channel. The wedge-shaped Coanda wall surface includes an upper wall surface and a lower wall surface. The secondary flow injection hole includes an upper secondary flow injection hole and a lower secondary flow injection hole. The main jet flow channel is connected to the secondary flow injection channel through the secondary flow injection hole, and the deflection control of the main jet flow is realized by changing the pressure in the secondary flow injection channel by the secondary flow control valve.

[0007] Further, the secondary flow control valve adopts one or several valves that can be proportionally adjusted, such as gate valves, butterfly valves, ball valves, plug valves, etc.

[0008] Furthermore, the upper secondary flow control valve and the lower secondary flow control valve control the pressure in the upper secondary flow injection channel and the lower secondary flow injection channel in a differential manner up and down.

[0009] Further, the secondary flow injection channel is used to introduce the gas around the nozzle into the main jet flow channel.

[0010] Further, the trailing edge of the wedge-shaped Coanda wall surface forms a certain angle.

[0011] Based on the method for regulating the linearity of the force vector angle control of the above passive fluid thrust vector nozzle, a force vector angle control curve with better linearity is quickly obtained. In this patent, a wedge-shaped nozzle with a ratio of the width to the height of the main jet flow channel of 5 and a trailing edge angle of the wedge-shaped Coanda wall surface of 120° is used as the regulation object, and the differential starting point of the secondary flow control valve is used to control the linearity of the force vector angle control curve when the jet velocity of the nozzle is 75 m / s, but the jet velocity and geometric configuration size of the nozzle are not limited to this. The force vector angle control curve of the nozzle under the actuation of the secondary flow control valve with different differential starting points is obtained by measuring the force with an aerodynamic balance, and the concavity and convexity of the control curve near the control quantity K = 0 are compared and the linear correlation coefficient R is calculated.2 , so as to obtain a control curve with the highest linearity that meets the engine control requirements as the preferred control curve of the nozzle, which specifically includes the following steps:

[0012] 1) Calculate the starting position of the differential of the secondary flow control valve

[0013]

[0014] where δ c is the starting point of the differential of the secondary flow control valve, S0 is the initial closing area of the unilateral secondary flow control valve given artificially, and S t is the total area of the unilateral secondary flow control valve.

[0015] 2) Calculate the actuation step of the secondary flow control valve

[0016]

[0017] where ΔS 闭 is the step of the secondary flow control valve actuating in the closing direction from the differential starting point, and ΔS 开 is the step of the secondary flow control valve actuating in the opening direction from the differential starting point, and m is the number of steps for the secondary flow control valve to actuate from the differential starting point to the open or closed state.

[0018] 3) Select several different differential starting points within the range of 0 - 100%, and use the formula in step 2 to calculate the actuation step of the secondary flow control valve respectively. Take the differential starting point as the starting point of the valve actuation. At the same time, control the upper (lower) secondary flow control valve to actuate in the opening direction, and the lower (upper) secondary flow control valve to actuate in the closing direction. The valve differential control amount corresponding to one actuation is K, and it is defined that the jet deflecting K to one side is positive, and deflecting K to the other side is negative. Measure the vector force components under different control amounts by the aerodynamic balance, calculate the force vector angle θ, and obtain the force vector angle control curve at the selected differential starting point.

[0019]

[0020] where F x is the axial thrust measured by the balance, and F y is the lateral force in the jet deflection direction measured by the balance.

[0021] 4) Calculate the linearity R of the force vector angle control curve in step 3, find the differential starting points corresponding to the two control curves with the highest linearity, and continue to select differential starting points within this range for aerodynamic balance force measurement until the linearity of the control curve reaches an optimal value.

[0022] Δ = max|θ - θ fit | (6)

[0023]

[0024] where θ fit is the force vector angle obtained by linear fitting under the same differential control amount of the valve, Δ is the maximum deviation of linear fitting, and θ max is the force vector angle when K = 100% obtained by linear fitting, and θ min is the force vector angle when K = -100% obtained by linear fitting.

[0025] The passive fluid thrust vector nozzle and the method for regulating the linearity of the force vector angle control disclosed by the present invention have the following beneficial effects:

[0026] By controlling the differential starting point of the bilateral secondary flow control valve, the linearity of the force vector angle control of the passive fluid thrust vector nozzle can be quickly regulated, which has the ability to adapt to different geometric configurations and jet velocities of the passive fluid thrust vector nozzle, reduces the R & D cycle and cost of the nozzle configuration design, solves the problem that the linearity of the force vector angle control of the pre - geometric fixed nozzle cannot be regulated, provides a solution for this type of passive fluid thrust vector nozzle to adapt to all working conditions and be reliably controlled on the aircraft, and further promotes its engineering practicability on the aircraft. Brief Description of the Drawings

[0027] Figure 1 is a schematic structural diagram of a passive fluid thrust vector nozzle in an embodiment of the present invention;

[0028] Figure 2 is Figure 1 a longitudinal sectional view of the symmetric plane of the passive fluid thrust vector nozzle shown;

[0029] Figure 3 is a force vector angle control curve diagram of the nozzle when the differential starting points are 0%, 30%, and 70% in an embodiment of the present invention;

[0030] Figure 4 is a comparison diagram of the linearity of the force vector angle control curves of the nozzle when the differential starting points are 0%, 30%, 50%, 60%, and 70% in an embodiment of the present invention.

[0031] Among them: 1, main jet flow channel; 2, upper secondary flow control valve; 3, lower secondary flow control valve; 4, upper secondary flow injection channel; 5, lower secondary flow injection channel; 6, upper wall surface; 7, lower wall surface; 8, secondary flow injection hole. Detailed Embodiments

[0032] The following will combine with the accompanying drawings to elaborate in detail on a passive fluid thrust vector nozzle and a method for regulating the linearity of the control of the force vector angle proposed by the present invention. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "left side", "right side", "upper part", "lower part", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second", etc. do not represent the importance of components, so it cannot be understood as a limitation to the present invention. The specific dimensions adopted in this embodiment are only for illustrating the technical solution by way of example and do not limit the protection scope of the present invention.

[0033] In this embodiment, taking Figures 1 to 2 a wedge-shaped passive fluid thrust vector nozzle shown as an example, it includes a main jet flow channel 1, an upper secondary flow control valve 2, a lower secondary flow control valve 3, an upper secondary flow injection channel 4, a lower secondary flow injection channel 5, an upper wall surface 6, a lower wall surface 7, and a secondary flow injection hole 8.

[0034] As Figure 2 shown, the main jet flow channel 1 is located between the upper secondary flow injection channel 4 and the lower secondary flow injection channel 5, and sucks the secondary flow from the secondary flow injection channel through the secondary flow injection hole 8. The upper secondary flow control valve 3 and the lower secondary flow control valve 4 are respectively installed on the outer sides of the upper secondary flow injection channel 4 and the lower secondary flow injection channel 5, and control the suction flow rate of the main jet flow to the secondary flow by controlling the opening area of the secondary flow injection channel. The upper wall surface 6 and the lower wall surface 7 are respectively deflected outward by a certain angle, and the Coanda effect of the jet flow is utilized to make the jet flow generate a stable large-angle deflection.

[0035] Based on the above-mentioned wedge-shaped passive fluid thrust vector nozzle, the method for quickly regulating its control linearity is as follows:

[0036] 1. Calculate the position of the differential starting point of the secondary flow control valve

[0037]

[0038] where δ c is the differential starting point of the secondary flow control valve, S0 is the initial closed area of the unilateral secondary flow control valve given artificially, and S t is the total area of the unilateral secondary flow control valve.

[0039] 2. Calculate the actuation step of the secondary flow control valve

[0040]

[0041] where ΔS 闭ΔS is the step length of the secondary flow control valve actuating in the closing direction from the differential starting point. 开 ΔS is the step length of the secondary flow control valve actuating in the opening direction from the differential starting point, and the number of steps for the secondary flow control valve to actuate from the differential starting point to the opening or closing is given as m = 10 steps.

[0042] 3. As Figure 3 shown, select 0%, 30%, and 70% differential starting points within the range of 0 - 100%, and use the formula in step 2 to calculate the actuation step lengths of the secondary flow control valve respectively. Take the differential starting point as the starting point of valve actuation. At the same time, control the upper (lower) secondary flow control valve to actuate in the opening direction, and the lower (upper) secondary flow control valve to actuate in the closing direction. The valve differential control amount corresponding to one actuation is K. Define that the jet deflecting K to one side is positive, and deflecting K to the other side is negative. Measure the vector force components under different control amounts by the aerodynamic balance, calculate the force vector angle θ, and obtain the force vector angle control curve at the selected differential starting points.

[0043]

[0044] Among them, F x is the axial thrust measured by the balance, and F y is the lateral force in the jet deflection direction measured by the balance.

[0045] 4. Calculate the linearity R of the force vector angle control curves in step 3, find the differential starting points (30% and 70%) corresponding to the two control curves with the highest linearity, continue to select 50% and 60% differential starting points within this range for aerodynamic balance force measurement, and compare the linearities of each curve again. Select the curve with the best linearity as the final control curve of the nozzle, as Figure 4 shown.

[0046] Δ = max|θ - θ fit | (6)

[0047]

[0048] Among them, θ fit is the force vector angle obtained by linear fitting under the same valve differential control amount, Δ is the maximum deviation of linear fitting, θ max is the force vector angle at K = 100% obtained by linear fitting, and θ min is the force vector angle at K = -100% obtained by linear fitting.

[0049] Based on the description of the preferred embodiments of the present invention, it should be clear that the present invention defined by the appended claims is not limited solely to the specific details set forth in the above specification, and many obvious changes to the present invention without departing from the spirit or scope of the present invention may equally achieve the purpose of the present invention.

Claims

1. A passive fluid thrust vector nozzle, characterized in that, It includes a main jet flow channel, a secondary flow control valve, a secondary flow injection channel, a wedge-shaped Coanda wall, and secondary flow injection holes; the secondary flow control valve includes an upper secondary flow control valve and a lower secondary flow control valve, the secondary flow injection channel includes an upper secondary flow injection channel and a lower secondary flow injection channel, the wedge-shaped Coanda wall includes an upper wall and a lower wall, and the secondary flow injection holes include upper secondary flow injection holes and lower secondary flow injection holes; The main jet flow channel is connected to the secondary flow injection channel through the secondary flow injection holes, and the deflection control of the main jet flow is achieved by changing the pressure in the secondary flow injection channel by the secondary flow control valve.

2. The passive fluid thrust vector nozzle according to claim 1, wherein, The secondary flow control valve adopts one or several of the valves that can be proportionally adjusted, such as gate valves, butterfly valves, ball valves, and plug valves.

3. The passive fluid thrust vector nozzle according to claim 2, characterized in that, The upper secondary flow control valve and the lower secondary flow control valve control the pressure in the upper secondary flow injection channel and the lower secondary flow injection channel in a differential manner up and down.

4. The passive fluid thrust vector nozzle according to claim 1, characterized in that, The secondary flow injection channel is used to introduce the gas around the nozzle into the main jet flow channel.

5. The passive fluid thrust vector nozzle according to claim 1, characterized in that, The trailing edge of the wedge-shaped Coanda wall forms a certain included angle.

6. The method for regulating the linearity of the force vector angle control of the passive fluid thrust vector nozzle according to any one of claims 1 to 5, characterized in that, Using the differential starting point of the secondary flow control valve to control the initial actuation position of the differential regulation of the valve, and quickly obtaining a force vector angle control curve with better linearity, specifically including the following steps: Control curve, specifically including the following steps: 1) Calculate the position of the differential starting point of the secondary flow control valve where δ c is the differential starting point of the secondary flow control valve, S0 is the initially closed area of the unilateral secondary flow control valve given artificially, and S t is the total area of the unilateral secondary flow control valve; 2) Calculate the actuation step length of the secondary flow control valve where ΔS 闭 is the step length of the secondary flow control valve actuating in the closing direction from the differential starting point, and ΔS 开 is the step length of the secondary flow control valve actuating in the opening direction from the differential starting point, and m is the number of steps of the secondary flow control valve actuating from the differential starting point to the opening or closing position; 3) Select several different differential starting points in the range of 0 to 100%, and use the formula in step 2 to calculate the actuation step length of the secondary flow control valve respectively; take the differential starting point as the starting point of the valve actuation, and at the same time control the upper (lower) secondary flow control valve to act in the opening direction, and the lower (upper) secondary flow control valve to act in the closing direction. The valve differential control amount corresponding to one actuation is K, and it is defined that the jet flow deflecting K to one side is positive, and deflecting K to the other side is negative; measure the vector force component under different control amounts by an aerodynamic balance, calculate the force vector angle θ, and obtain the force vector angle control curve under the selected differential starting point; Among which F x is the axial thrust measured by the balance, and F y is the lateral force in the jet deflection direction measured by the balance; 4) Calculate the linearity R of the force vector angle control curve in step 3, find the differential starting points corresponding to the two control curves with the highest linearity, and continue to select differential starting points in this range for aerodynamic balance force measurement until the linearity of the control curve reaches a better value; Δ=max|θ - θ fit | (6) where θ fit is the force vector angle obtained by linear fitting under the differential control quantity of the same valve, Δ is the maximum deviation of linear fitting, θ max is the force vector angle when K = 100% obtained by linear fitting, θ min is the force vector angle when K = -100% obtained by linear fitting.

Images