Method for establishing supersonic air inlet duct end shock wave control model based on bypass deflation

Abstract

The invention belongs to the field of supersonic aircraft air inlet channels, and provides a method for establishing a supersonic air inlet channel end shock wave control model based on bypass deflation. According to the method, a shock wave position-back pressure reference relation under the bypass-free deflation condition is deduced by establishing a variable cross-section pipeline one-dimensional steady isentropic flow model; and then bypass deflation parameters are introduced, a dynamic model of the shock wave position changing along with the back pressure and the deflation area is established, and a bivariate prediction model is constructed through coefficient expansion. In order to improve the engineering applicability, the equivalent air inlet channel simulation research data is adopted to correct the model coefficient, the complex physical effect in real flow is compensated, and the prediction precision and universality are remarkably improved. And finally, closed-loop control design is completed based on the ending shock wave control model, the target of actively regulating and controlling the position of the ending shock wave through the change of the deflation area is achieved, and an effective solution is provided for flow stability control of the supersonic air inlet channel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of supersonic aircraft inlet, in particular to a method for establishing a control model of the terminal shock wave of a supersonic inlet based on bypass air release. BACKGROUND

[0002] As the core component of high-speed aircraft propulsion system, the core function of supersonic inlet is to slow down and pressurize the high-speed incoming flow and deliver it to the combustion chamber. Under supersonic flow conditions, there is usually a complex flow structure in the inlet, and the stability of the terminal shock wave directly affects the total pressure recovery coefficient, flow stability and engine matching performance. If the terminal shock wave moves forward too much, it may cause the inlet to not start, causing surging and even structural damage. If the shock wave moves backward, it will reduce the total pressure recovery efficiency and affect the engine thrust. Traditional shock wave control methods rely on geometric adjustment, simple open-loop bleed or fuel flow adjustment, which is difficult to cope with complex conditions such as sudden changes in flight Mach number and angle of attack, and even adjusting the fuel supply will sacrifice engine thrust.

[0003] In recent years, bypass air release technology has been introduced into the field of shock wave control due to its simple structure and rapid response, but existing research still has significant limitations: first, there is no universal model for the quantitative relationship between bypass air release parameters (such as air release area) and shock wave position, especially when the air release area and outlet static pressure interact, the nonlinear coupling mechanism is not clear; second, the theoretical model does not correct the viscous dissipation and complex wave interference in actual flow, resulting in a large deviation in engineering application; third, there is a lack of active control strategies based on multivariate real-time prediction, making it difficult to achieve rapid and stable shock wave position. Therefore, it is urgent to develop a terminal shock wave control model that integrates high-precision double-variable prediction, viscous effect correction and dynamic closed-loop control to improve the robustness and adaptability of supersonic inlets under complex conditions. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method for establishing a control model of the terminal shock wave of a supersonic inlet based on bypass air release, which solves the problem of accurate control of the position of the terminal shock wave and improves the anti-interference ability and stability of the inlet.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is:

[0006] The method for establishing a control model of the terminal shock wave of a supersonic inlet based on bypass air release, characterized in that it comprises the following steps:

[0007] Step 1, the inlet is a variable cross-section pipe; according to the one-dimensional steady isentropic flow equation, the terminal shock wave position x in the inlet and the outlet static pressure p ea function relationship between the end shock wave position x and the exit static pressure p

[0008] Step 2, a bypass bleed slot is opened in the sidewall of the inlet; a bypass bleed parameter is introduced on the basis of the end shock wave position reference model, the bypass bleed parameter includes a bleed area ratio σ; a function relationship between the end shock wave position x and the exit static pressure p e under different bleed area ratios σ is derived, and an end shock wave position dynamic model with varying coefficients with the bleed area ratio σ is obtained;

[0009] Step 3, the coefficients of the end shock wave position dynamic model are respectively expanded as functions of the bleed area ratio σ, and an end shock wave position bivariate prediction model related to the bleed area ratio σ and the exit static pressure p e is constructed;

[0010] Step 4, a simulation inlet aerodynamically equivalent to the variable cross-section duct is established; under the condition that the bleed area ratio σ is constant, a function relationship between the end shock wave position x' in the simulation inlet and the exit static pressure p e is derived, and the coefficients of the end shock wave position bivariate prediction model are corrected to obtain an end shock wave control model based on bypass bleed control;

[0011] Step 5, based on the design requirements of the inlet, the target position x target of the end shock wave is set, and the exit static pressure p e and the actual bleed area ratio σ real are monitored in real time;

[0012] The target value σ cmd of the bleed area ratio is calculated through the target position x target of the end shock wave, the exit static pressure p e , and the end shock wave control model of the supersonic inlet;

[0013] The actual bleed area ratio σ real is dynamically adjusted so that the difference between the actual bleed area ratio σ real and the target value σ cmd of the bleed area ratio is within a threshold value, the end shock wave position x is stabilized at the target position x target of the end shock wave, and the closed-loop control of the end shock wave position x is completed.

[0014] As preferred, in step 1, the method for constructing the end shock wave position reference model specifically includes: calculating the end shock wave position x and the exit static pressure p e , and fitting a quadratic function through the least square method:

[0015]

[0016] Wherein, a0, b0, c0 are the fitting coefficients under the condition of no bypass bleed.

[0017] As preferred, in step 2, the bypass bleed parameters further include the bleed slot exit static pressure p slot ; the bleed area ratio A slot is the bleed area, A inlet is the variable cross-section duct inlet area.

[0018] As preferred, in step 2, the method for constructing the shock position dynamic model specifically includes:

[0019] Step 2-1, selecting n groups of bleed area ratios σ and m groups of bleed slot exit static pressures p slot , calculating the end shock position x and the exit static pressure p e , and fitting them into a quadratic function by the least square method:

[0020]

[0021] wherein, is a dynamic coefficient related to the bypass bleed parameters;

[0022] Step 2-2, keeping the bleed slot exit static pressure p slot unchanged, simplifying a(σ i ), b(σ i ), c(σ i )(i = 1, 2, …, n), and combining the shock position reference model to obtain the shock position dynamic model with the bypass bleed parameters changing:

[0023]

[0024] As preferred, in step 3, the method for constructing the bivariate prediction model specifically includes:

[0025] Step 3-1, fitting the n groups of dynamic coefficients a(σ i ), b(σ i ), c(σ i ) in formula (3) into quadratic functions with the bleed area ratio σ as the independent variable by the least square method:

[0026] a(σ) = k a2 σ 2 + k a1 σ + k a0

[0027] b(σ) = k b2 σ 2 + k b1 σ + k b0

[0028] c(σ = kc2 σ 2 +k c1 σ+k c0

[0029] wherein, k a2 , k a1 , k a0 is the calibration coefficient of the quadratic term coefficient a(σ);

[0030] k b2 , k b1 , k b0 is the calibration coefficient of the linear term coefficient b(σ);

[0031] k c2 , k c1 , k c0 is the calibration coefficient of the constant term coefficient c(σ);

[0032] Step 3-2, modeling by dynamic coefficient quadratic function, the exit static pressure p e and the bleed area ratio σ are brought into formula (3) to form the complete mapping relationship of x = f(p e , σ) and to construct the shock position bivariate prediction model:

[0033]

[0034] As preferred, in step 4, the simulation inlet duct considers the viscous stress and background wave system influence, the aerodynamic parameters of the throat interface thereof are consistent with the inflow conditions of the variable cross-section pipeline inlet; the bypass bleed parameters and the cross-sectional area variation law of the expansion section are consistent with the variable cross-section pipeline.

[0035] As preferred, in step 4, the construction method of the end shock control model based on bypass bleed control specifically includes:

[0036] n groups of bleed area ratios σ are selected, which are the same in numerical size as those in step 2; the bleed area ratio σ i and the end shock position x' in the lower inlet duct are calculated, which change with the exit static pressure p e , and the simulation data of the end shock position x' in the lower inlet duct changing with the exit static pressure p e are fitted into a quadratic function by the least square method:

[0037]

[0038] wherein, a'(σ i ), b'(σ i ), c'(σ i ) are the simulation fitting coefficients;

[0039] Under the same bleed area ratio σ i , the correction relationship of the simulation fitting coefficients of formula (5) and the coefficients of formula (3) is:

[0040] a′(σ i )=A′(σ i )*a(σ i )

[0041] b′(σ i )=B′(σ i )*b(σ i )

[0042] c′(σ i )=C′(σ i )*c(σ i )

[0043] Where, A'(σ i ), B'(σ i ), G'(σ i ) is a correction factor used to compensate for prediction biases caused by complex physical effects in the actual flow.

[0044] Preferably, in step 4, the correction coefficient A'(σ) for the n groups of venting area ratios is adjusted using the least squares method. i ), B'(σ i ), C'(σ i (i = 1, 2, ..., n) are fitted with the following values, with the venting area ratio σ as the independent variable:

[0045] A'(σ)=m A2 σ 2 +m A1 σ+m A0

[0046] B'(σ)=m B2 σ 2 +m B1 σ+m B0

[0047] C'(σ)=m C2 σ 2 +m C1 σ+m C0

[0048] Where, m A2 m A1 m A0 The calibration coefficients are for the quadratic term correction coefficients A'(σ).

[0049] m B2 m B1 m B0 The calibration coefficient is the correction factor B'(σ) for the first-order term;

[0050] m C2 mC1 , m C0 is the calibration coefficient of constant term correction coefficient C'(σ)

[0051] The dynamic correction coefficients A'(σ), B'(σ), and C'(σ) are brought into formula (4) to obtain a bypass bleed control-based terminal shock control model:

[0052]

[0053] As preferred, the closed-loop control design specifically includes the following steps:

[0054] Step 5-1, determining the terminal shock target position x according to the design requirements of the inlet channel target , setting the adjustable range of the bleed area ratio σ and the fluctuation range of the outlet static pressure p e ; real-time monitoring of the outlet static pressure p e and the current bleed area ratio σ;

[0055] Step 5-2, calculating the target value σ cmd of the bleed area according to the current outlet static pressure p e and the terminal shock target position x target , through the bypass bleed control-based terminal shock control model;

[0056] Step 5-3, dynamically adjusting the bleed area with an ADRC self-anti-disturbance controller, which includes a tracking differentiator, an extended state observer, and a nonlinear state error feedback control law;

[0057] The tracking differentiator receives σ cmd , generates a smooth transition tracking signal σ track and its differential signal

[0058] The extended state observer receives the actual bleed area ratio σ real and the control variable u of the actuator in real time, estimates the current bleed area state change rate and unifies the model prediction error, actuator hysteresis, and air flow disturbance as total disturbance

[0059] The nonlinear state error feedback control law calculates the tracking error and the differential error , combines the total disturbance to generate the control variable to drive the actuator to act;

[0060] where k p , k d are proportional-differential gains, and b0 is a control input gain;

[0061] Step 5-4: The actuator makes a dynamic response, converting the control quantity u output by the ADRC controller into a change in the venting area;

[0062] Step 5-5: Calculate the actual venting area ratio σ real Ratio of target venting area σ cmd The difference, if |σ real -σ cmd If the threshold ∈, then repeat steps 5-2 to 5-5 to form a closed-loop control of the final shock wave x.

[0063] Preferably, in step 5-2, the target value of the venting area σ cmd The calculation method is as follows:

[0064] x target =f(σ,p e )

[0065] σ cmd =argmin|f(σ,p e )-x target |

[0066] When the outlet static pressure p e During sudden changes, the shock wave control model at the end of the supersonic inlet is updated in real time with σ. cmd .

[0067] The present invention has the following beneficial effects:

[0068] 1. This invention establishes a bivariate explicit functional relationship between the position of the terminal shock wave, the ratio of the venting area, and the static pressure at the inlet outlet, thereby obtaining a control model for the terminal shock wave of a supersonic inlet. This solves the problem of the lack of quantitative relationship between typical bypass venting parameters and the position of the terminal shock wave, and clarifies the nonlinear coupling mechanism when the venting area and the outlet static pressure work together.

[0069] 2. Based on simulation data from an equivalent inlet model, this invention corrects the coefficients of the final shock wave control model, compensating for the shock wave position prediction deviation caused by complex physical effects in real flow, such as viscous dissipation and complex wave system interference, effectively improving the accuracy and universality of the model in practical engineering applications.

[0070] 3. This invention uses a tail shock wave control model to quickly calculate the optimal venting area command in real time based on sudden changes in back pressure. Combined with an ADRC active disturbance rejection controller, the venting area ratio is adjusted with high precision to stabilize the tail shock wave position. The entire closed-loop control system has a fast response speed, high dynamic performance, and strong anti-interference capability. Attached Figure Description

[0071] Figure 1This is a flowchart illustrating the construction of the supersonic inlet tail shock wave control model based on bypass venting control according to the present invention.

[0072] Figure 2 This is a schematic diagram of a one-dimensional steady isentropic flow variable cross-section pipe according to the present invention.

[0073] Figure 3 This is a schematic diagram of the variable cross-section pipe after the venting joint is opened according to the present invention.

[0074] Figure 4 This is a two-dimensional schematic diagram of the aerodynamic equivalent intake duct model of the present invention.

[0075] Figure 5 This is a schematic diagram of the working principle of the ADRC active disturbance rejection controller of the present invention.

[0076] Figure 6 This is a flowchart of the shock wave closed-loop control based on the supersonic inlet end shock wave control model of the present invention.

[0077] Figure 7 This is a diagram illustrating the effect of the final shock wave closed-loop control in this invention. Detailed Implementation

[0078] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0079] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0080] like Figures 1-7 As shown, the method for establishing a supersonic inlet tail shock wave control model based on bypass venting includes the following steps:

[0081] Step 1: The intake duct is a variable cross-section pipe; based on the one-dimensional steady isentropic flow equation, derive the position x of the final shock wave in the intake duct and the static pressure p at the outlet. e The functional relationship is used to obtain the shock wave position reference model under the condition of no bypass venting.

[0082] In this embodiment, the air intake is established as follows: Figure 2 The variable cross-section pipe model shown is used to deduce the relationship between the position x of the normal shock wave (terminal shock wave) and the outlet static pressure p in the pipe, based on the one-dimensional steady isentropic flow equation. efunction of back pressure value; considering the derived x-p e relationship form is complex, involving transcendental function and multi-parameter coupling, which is difficult to be directly used in engineering control, therefore, a large number of data points are generated by numerical calculation based on the derived x-p e relationship (fixed inlet condition, shock position is solved by traversing back pressure value), and then a quadratic function form with minimum error and most consistent regularity is fitted by least square method to obtain the baseline model of shock position under the condition of no bypass bleeding:

[0083]

[0084] wherein a0, b0, c0 are fitting coefficients, which are related to the geometric parameters of the pipeline (such as the change rate of cross-sectional area) and the inlet flow conditions (such as Mach number, inlet static pressure).

[0085] Step 2: A bypass bleeding slot is opened on the side wall of the inlet channel; on the basis of the baseline model of shock position, a bypass bleeding parameter is introduced, the bypass bleeding parameter includes a bleeding area ratio σ; the function relationship between the end shock position x and the outlet static pressure p e under different bleeding area ratios σ is derived to obtain the dynamic model of shock position with the change of the bleeding area ratio σ.

[0086] In this embodiment, as shown in Figure 3 , a bleeding slot is opened on the single side wall of the variable cross-section pipeline, the outlet static pressure of the bleeding slot is represented by p slot , the bleeding area ratio σ (A slot is the bleeding area, A inlet is the inlet area of the variable cross-section pipeline) is defined, the function relationship between the normal shock position x and the outlet static pressure p e under different bypass bleeding parameters is derived by modifying the mass flow equation; a large number of data points are generated by numerical calculation based on the derived x, p e relationship (fixed inlet condition, n groups of bleeding area ratios are selected, m groups of outlet static pressures of the bleeding slot, and the shock position is solved by traversing the back pressure value), and then a quadratic function form with minimum error and most consistent regularity is fitted by least square method:

[0087]

[0088] wherein, is the dynamic coefficient related to the bypass bleeding parameter, which is related to the bleeding area ratio σ and the outlet static pressure p slot of the bleeding slot, and represents the nonlinear influence of the bypass bleeding on the shock position; for each group of σi and , there is a group of matching dynamic coefficients;

[0089] the outlet static pressure p slotInvariable, the dynamic coefficient is only affected by the bleed area ratio σ, which can be expressed by a(σ i ), b(σ i ), c(σ i )(i = 1, 2, …, n). Combined with the shock position reference model under the bypass-free bleed condition described in step 1, the dynamic model of the shock position with varying bleed area can be obtained:

[0090]

[0091] Step 3: Expand each coefficient of the dynamic model of the shock position into a function of the bleed area ratio σ, and construct a two-variable prediction model of the shock position related to the bleed area ratio σ and the outlet static pressure p e .

[0092] In this embodiment, the n sets of dynamic coefficients a(σ i ), b(σ i ), c(σ i )(i = 1, 2, …, n) in the dynamic model of the shock position described in step 2 are extracted, and through the least square method, they are respectively fitted into a quadratic function form with the bleed area ratio σ as the independent variable, and the error is minimized and the regularity is most consistent:

[0093] a(σ) = k a2 σ 2 + k a1 σ + k a0

[0094] b(σ) = k b2 σ 2 + k b1 σ + k b0

[0095] c(σ) = k c2 σ 2 + k c1 σ + k c0

[0096] Wherein, k a2 , k a1 , k a0 are the calibration coefficients of the quadratic term a(σ); k b2 , k b1 , k b0 are the calibration coefficients of the linear term b(σ); k c2 , k c1 , k c0 are the calibration coefficients of the constant term c(σ); the coefficient k is calibrated by fitting the full working condition data to ensure the adaptability of the model in a wide range;

[0097] By modeling the outlet static pressure p using a quadratic function with dynamic coefficients, e Incorporating the venting area ratio σ into a unified equation, we obtain x = f(p) e Based on the complete mapping relationship of ,σ), a bivariate prediction model for shock wave location is constructed:

[0098]

[0099] Step 4: Establish a simulated air intake duct aerodynamically equivalent to a variable cross-section pipe; under the condition that the exhaust area ratio σ remains constant, derive the position x' of the final shock wave and the outlet static pressure p within the simulated air intake duct. e The functional relationship was determined, and the coefficients of the bivariate prediction model for shock wave location were corrected to obtain the terminal shock wave control model based on bypass venting control.

[0100] In this embodiment, an intake duct model aerodynamically equivalent to a variable cross-section pipe is constructed to... Figure 4 Taking the two-dimensional inlet model shown as an example, numerical simulation studies are carried out under the condition of considering the influence of viscous stress and background wave system. The inlet model must ensure that the aerodynamic parameters of the throat interface are consistent with the inflow conditions of the variable cross-section pipe inlet, that the bypass venting parameters of the expansion section (such as bypass position, venting area ratio and venting outlet static pressure) are consistent with the variable cross-section pipe, and that the cross-sectional area variation law of the expansion section is consistent with the variable cross-section pipe.

[0101] With the intake flow conditions unchanged, select n groups of exhaust area ratios with the same values ​​as in step 2, and iterate through the back pressure values ​​to solve for the position of the final shock wave, thus obtaining the exhaust area ratio σ for each group. i The position x' of the tail shock wave in the lower intake duct varies with the outlet static pressure p e The changing simulation data is then fitted using the least squares method to obtain a quadratic function form with the smallest error and the best regularity:

[0102]

[0103] Where, a'(σ i ), b'(σ i ), c'(σ i The simulation fitting coefficients are determined by the coupling of multiple factors, including the geometry of the expansion section, bypass venting parameters, boundary layer thickness, and background wave interference.

[0104] Under the same venting area ratio σ i Below, establish the simulation fitting coefficients a'(σ) i ), b'(σ i ), c'(σ i The coefficients a(σ) of the bivariate prediction model for shock wave location described in step 3 are the same as those of the model described in step 3. i ), b(σ i ), c(σ)i The modification relationship of )

[0105] a′(σ i )=A′(σ i )*a(σ i )

[0106] b′(σ i )=B′(σ i )*b(σ i )

[0107] c′(σ i )=C′(σ i )*c(σ i )

[0108] Where, A'(σ i ), B'(σ i ), C'(σ i () is a correction coefficient to compensate for prediction biases caused by complex physical effects in real flow, thereby improving the accuracy and universality of the model in practical engineering applications.

[0109] Extract the correction coefficient A'(σ) for n groups of venting area ratios. i ), B'(σ i ), C'(σ i (i=1,2,…,n), using the least squares method, they are fitted into quadratic functions with the venting area ratio σ as the independent variable, exhibiting the smallest error and the best regularity:

[0110] A'(σ)=m A2 σ 2 +m A1 σ+m A0

[0111] B'(σ)=m B2 σ 2 +m B 1σ+m B0

[0112] C'(σ)=m C2 σ 2 +m C1 σ+m C0

[0113] Where, m A2 m A1 m A0 The calibration coefficients for the quadratic term correction coefficient A'(σ); m B2 m B1 m B0 The calibration coefficient for the linear term correction factor B'(σ); m C2 mC1 , m C0 is the calibration coefficient of the constant term correction coefficient C'(σ);

[0114] Substitute the correction coefficient into the shock position bivariate prediction model described in step 3 to finally obtain the supersonic inlet terminal shock control model based on bypass bleed control:

[0115]

[0116] The model shows that the terminal shock position x is determined by the bleed area ratio σ and the outlet static pressure p e , and in actual regulation, p e is affected by external flow conditions (such as flight Mach number and attack angle), while σ can be actively adjusted by a mechanical actuator, so the core means of regulation is to compensate for the change of p e by adjusting σ, so that the terminal shock is stabilized at the target position.

[0117] Step 5: Based on the design requirements of the inlet, set the target position x target of the terminal shock, and monitor the outlet static pressure p e and the actual bleed area ratio σ real in real time; calculate the target value σ cmd of the bleed area ratio by the target position x target of the terminal shock, the outlet static pressure p e , and the supersonic inlet terminal shock control model; dynamically adjust the actual bleed area ratio σ real so that the difference between the actual bleed area ratio σ real and the target value σ cmd of the bleed area ratio is within the threshold, the terminal shock position x is stabilized at the target position x target of the terminal shock, and the closed-loop control of the terminal shock position x is completed.

[0118] In this embodiment, the shock closed-loop control design is based on the supersonic inlet terminal shock control model described in step 4, and the specific closed-loop control process is shown in Figure 6 ;

[0119] Step 5.1: According to the design requirements of the inlet (such as avoiding inlet stall, improving total pressure recovery, or matching the inlet conditions of the combustion chamber), determine the target position x target of the terminal shock, set the adjustable range of the bleed area ratio σ and the fluctuation range of the outlet static pressure p e ; monitor the outlet static pressure p e and the current bleed area ratio σ in real time, and the data sampling frequency should be higher than the flow characteristic frequency to avoid phase delay;

[0120] Step 5.2: Based on the supersonic inlet terminal shock control model described in step 4, according to the current outlet static pressure p e and the target position of the terminal shock x target , the required bleed area ratio σ cmd is solved by inverse solution: Since the equation is nonlinear, numerical methods (such as Newton-Raphson iteration method) are used to solve it:

[0121] x target = f(σ, p e )

[0122] σ cmd = argmin | f(σ, p e )- x target |

[0123] When the outlet static pressure p e changes suddenly, the supersonic inlet terminal shock control model updates σ cmd in real time.

[0124] Step 5.3: As shown in Fig. Figure 5 , the ADRC self-disturbance controller is used for dynamic adjustment of the bleed area; the ADRC controller consists of a tracking differentiator (TD), an extended state observer (ESO), and a nonlinear state error feedback control law (NLSEF); the tracking differentiator (TD) receives σ cmd , generates a smooth transition tracking signal σ track and its differential signal to avoid oscillation of the actuator due to sudden changes in the command; the extended state observer (ESO) receives the actual bleed area ratio σ real and the control variable u in real time, estimates the current bleed area state and its rate of change , and considers model prediction error, actuator hysteresis, and air flow disturbance as total disturbance The nonlinear state error feedback control law (NLSEF) calculates the tracking error and the differential error Combining the total disturbance , the control variable u is generated to drive the actuator to act; where k p and k d are proportional-differential gains, and b0 is the control input gain (related to the response characteristics of the actuator);

[0125] Step 5.4: The actuator responds dynamically, converting the control variable u output by the ADRC controller into a bleed area change, so that the actual bleed area ratio σ real approaches σ cmd .

[0126] Step 5.5: Calculate the actual venting area ratio σ real Ratio of target venting area σ cmd deviation, if |σ real -σ cmd If |>∈(threshold), then repeat steps 5.2 to 5.5 to form a closed-loop control of the final shock wave.

[0127] The final shock closed-loop control results are as follows Figure 7 As shown, the position of the final shock wave is dimensionless, and the target value of the final shock wave position is set to x. target =0.1. Wherein, the position of the intake throat is defined as x start =0, the intake outlet position is defined as x end =1. In the initial stage (0s≤t<0.05s), the final shock wave is located downstream of the target position. As the static pressure at the intake outlet continues to increase, the final shock wave propagates upstream. At this time, the venting slot is closed. At the critical point (t=0.05s), the final shock wave propagates to the target position x. target =0.1, the static pressure at the intake outlet continues to increase; during the closed-loop control phase (0.06s≤t<0.15s), the final shock wave crosses the target position and continues to move upstream. At this time, the venting slot opens, and the closed-loop control system dynamically adjusts the venting area ratio according to the real-time monitored changes in the static pressure at the intake outlet, so that the final shock wave stabilizes at the target position x. target =0.1; In the final stage (t≥0.15s), the static pressure at the intake outlet stabilizes at 6 times the incoming static pressure, the exhaust area ratio stabilizes at 0.13, and the final shock wave is stably controlled at the target position x. target =0.1. The closed-loop control result of the final shock wave successfully stabilized the final shock wave at the preset target position, significantly suppressing the excessive forward movement of the shock wave caused by the large increase in the static pressure at the intake outlet, and the control effect was significant.

[0128] It should be noted that the closed-loop control results of the final shock wave described in this specific embodiment (such as...) Figure 7 As shown, this is mainly used to verify the feasibility of the closed-loop control method. In practical engineering applications, control parameters (such as the target position of the final shock wave, the static pressure variation at the intake outlet, ADRC controller parameter tuning and dynamic response speed, and actuator response characteristics) can be adjusted and optimized according to the specific intake configuration and operating conditions.

[0129] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A method for establishing a model of shock control at the end of a supersonic inlet based on bypass air bleed, characterized in that, The method comprises the following steps: Step 1, the inlet is a variable cross-section duct; according to the one-dimensional steady isentropic flow equation, the function relationship between the position of the terminal shock wave x and the outlet static pressure p of the inlet is derived to obtain a reference model of the position of the shock wave under the condition of no bypass bleeding; e ​ Step 2, opening bypass air release slots in the side wall of the air inlet channel; introducing bypass air release parameters on the basis of the shock position reference model, the bypass air release parameters including an air release area ratio σ; deriving a function relationship between the end shock position x and the outlet static pressure p under different air release area ratios σ, to obtain a shock position dynamic model with the coefficients changing with the air release area ratio σ; e Step 3, introducing the bypass air release parameters into the reference model, and obtaining the bypass air release model of the air inlet channel. Step 3, the coefficients of the dynamic model of shock position are expanded into functions of the area ratio σ, and a double-variable prediction model of shock position related to the area ratio σ and the outlet static pressure p e a relevant shock position double-variable prediction model; Step 4, the simulation inlet duct aerodynamically equivalent to the variable cross-section duct is established; under the condition of constant area ratio σ, the function relationship between the end shock wave position x' in the simulation inlet duct and the outlet static pressure p e is derived, and the coefficients of the double variable prediction model of the shock wave position are modified to obtain the end shock wave control model based on bypass bleed control; Step 5, set the target position x of the terminal shock based on the design requirements of the inlet target and monitor the outlet static pressure p in real time e and the actual bleed area ratio σ real ; By the end shock target position x target , exit static pressure p e , and supersonic inlet end shock control model to calculate the bleed area ratio target value σ cmd ; The actual bleed area ratio σ real is dynamically adjusted so that the difference between the actual bleed area ratio σ real and the bleed area ratio target value σ cmd is within a threshold value, the terminal shock position x is stabilized at the terminal shock target position x target , and closed-loop control of the terminal shock position x is completed.

2. The method of claim 1, wherein, In step 1, the method for constructing the shock position reference model specifically comprises: calculating the position x of the trailing shock and the outlet static pressure p e and fitting it into a quadratic function by the least square method: Wherein a0, b0, c0 are fitting coefficients under the condition of no bypass air release.

3. The method of claim 2, wherein, In step 2, the bypass bleed parameter also includes the bleed slot exit static pressure p slot ; the bleed area ratio A slot is the bleed area, A inlet is the variable area duct inlet area.

4. The method of claim 3, wherein, The method for constructing the shock wave position dynamic model in step 2 specifically comprises: Step 2-1, select n groups of the area ratio σ, m groups of the exit static pressure p of the exhaust slot slot , calculate the position x of the terminal shock wave and the exit static pressure p e , and fit them into a quadratic function by the least square method: wherein, is a dynamic coefficient related to the bypass bleed parameter; Step 2-2, keep the static pressure p of the air release gap outlet slot Invariable, Simplify a(σ i ), b(σ i ), c(σ i )(i = 1, 2, …, n), combined with the shock wave position reference model, the dynamic model of the shock wave position with the change of the road air release parameters is obtained:

5. The method of claim 4, wherein, The method for constructing the bivariate prediction model in step 3 specifically comprises: Step 3-1: Using the least squares method, the n sets of dynamic coefficients a(σ) in formula (3) are... i ), b(σ i ), c(σ) i The functions are fitted to represent quadratic functions with the venting area ratio σ as the independent variable: a(σ) = k a2 σ 2 +k a1 σ+k a0 b(σ) = k b2 σ 2 +k b1 σ+k b0 c(σ) = k c2 σ 2 +k c1 σ+k c0 where k a2 , k a1 , k a0 are calibration coefficients of the quadratic term coefficient a(σ). k b2 , k b1 , k b0 is a scaling factor for the linear term coefficient b(σ); k c2 , k c1 , k c0 is a calibration coefficient of the constant term coefficient c(σ); Step 3-2, modeling by dynamic coefficient quadratic function, the exit static pressure p e With the air release area ratio σ into formula (3), forming x = f(p e , σ) complete mapping relationship, to build a shock location bivariate prediction model:

6. The method of claim 5, wherein, In step 4, the simulation inlet duct considers viscous stress and background wave system influence, the aerodynamic parameters of the throat interface are consistent with the inflow conditions of the variable cross-section pipeline inlet, the bypass air release parameters and the cross-section area change law of the expansion section are consistent with the variable cross-section pipeline.

7. The method of claim 6, wherein, The method for constructing the end shock wave control model based on bypass air release control in step 4 specifically comprises: Select n groups of the same size of the value of the exhaust area ratio σ in step 2; calculate the exhaust area ratio σ of each group i The position of the terminal shock wave in the lower intake x' varies with the exit static pressure p e The simulation data of the change is fitted into a quadratic function by the least square method: Where, a'(σ i ), b'(σ i ), c'(σ i ) represents the simulation fitting coefficients; At the same venting area ratio σ i The simulation fitting coefficients of formula (5) and the correction relationship of the coefficients of each term of formula (3) are as follows: a'(σ i ) = A'(σ i )*a(σ i ) b'(σ i ) = B'(σ i )*b(σ i ) c'(σ i ) = C'(σ i )*c(σ i ) Where, A'(σ i ), B'(σ i ), C'(σ i ) is a correction factor used to compensate for prediction biases caused by complex physical effects in the actual flow.

8. The method of claim 7, wherein, In Step 4, the n sets of correction coefficients A'(σ i ), B'(σ i ), and C'(σ i )(i = 1, 2, …, n) are fitted by least squares to be functions of the blow area ratio σ as independent variables: A'(σ) = m A2 σ 2 +m A1 σ+m A0 B'(σ) = m B2 σ 2 +m B1 σ+m B0 C'(σ) = m C2 σ 2 +m C1 σ+m C0 where m A2 , m A1 , m A0 is a calibration coefficient of the quadratic term correction coefficient A'(σ). m B2 , m B1 , m B0 is a calibration coefficient of the linear term correction coefficient B'(σ); m C2 , m C1 , m C0 is a calibration coefficient of the constant term correction coefficient C'(σ) The dynamic correction coefficients A'(σ), B'(σ) and C'(σ) are brought into formula (4) to obtain the end shock wave control model based on bypass air release control:

9. The method of claim 8, wherein, The closed-loop control design specifically comprises the following steps: Step 5-1, according to the design requirements of the inlet, determine the target position x of the end shock wave target , set the adjustable range of the bleed area ratio σ and the fluctuation range of the outlet static pressure p e ; real-time monitor the outlet static pressure p e and the current bleed area ratio σ; Step 5-2, calculating the target value of the exit static pressure p e and the end shock wave target position x target by the end shock wave control model based on the bypass bleed control cmd ; Step 5-3, the ADRC active disturbance rejection controller is used for dynamically adjusting the air release area, and the ADRC active disturbance rejection controller comprises a tracking differentiator, an extended state observer and a nonlinear state error feedback control law; The tracking differentiator receives σ cmd generates a smooth transition tracking signal σ track and its differential signal The extended state observer receives the actual deflation area ratio σ of the actuator in real time real and the control variable u, estimates the current deflation area state The rate of change and the model prediction error, actuator hysteresis, air flow disturbance, etc. are unified as total disturbance nonlinear state error feedback control law computes tracking error and derivative error combined total disturbance generates control quantity drives actuator to act where k p , k d is a proportional-derivative gain, and b0is a control input gain; Step 5-4, the actuator makes a dynamic response, and converts the control amount u output by the ADRC controller into an air release area change. Step 5-5, calculate the actual bleed area ratio σ real and the difference between the target bleed area ratio σ cmd , if |σ real - σ cmd |> threshold ∈, repeat step 5-2 to step 5-5 to form a closed-loop control of the terminal shock wave x.

10. The method of claim 9, wherein, In Step 5-2, the target value σ of the outflow area cmd The calculation is as follows: x target = f(σ, p e ) σ cmd = argmin | f(σ, p e ) - x target | When the exit static pressure p e The shock control model at the end of the supersonic inlet is updated in real time σ cmd .

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