A control design method to improve the wide-range starting characteristics of the intake port

Abstract

This invention discloses a control design method for improving the wide-range starting characteristics of an inlet. This method, which belongs to the field of flow control, includes: acquiring and storing numerical simulation flow field data for the inlet; analyzing the flow field characteristics at different Mach numbers based on the flow field data to determine the inlet's non-starting range; selecting the position of a control device based on the flow field characteristics; and verifying the effectiveness of the control device and optimizing the control parameters based on the inlet's non-starting range to complete the control design for improving the wide-range starting characteristics of the inlet. This invention solves the problem that existing flow control methods often focus on a single interference factor and have difficulty coordinating the coupling effects of shock wave structure and geometric contraction.

Description

Technical Field

[0001] The present invention belongs to the field of flow control, and in particular relates to a control design method for improving wide-range starting characteristics of an intake duct. Background Art

[0002] As the core propulsion solution for achieving hypersonic flight (Ma ≥ 5) within the atmosphere, air-breathing scramjets have become a key research focus for next-generation aerospace vehicles due to their advantages, including the absence of an oxidizer, high thrust-to-weight ratio, and compact design. As a key aerodynamic component of the engine, the supersonic inlet compresses the high-enthalpy incoming air and maintains a stable supersonic flow field at the combustor inlet. Its performance directly determines the propulsion system's thermodynamic cycle efficiency and the vehicle's adaptability over a wide speed range. However, under wide-speed flight conditions (e.g., Ma = 2-8), the inlet must balance compression efficiency and flow stability in an extreme aerodynamic and thermodynamic environment: it must optimize the shock wave design at high Mach numbers to improve the total pressure recovery coefficient, while also suppressing the large-scale separation flow caused by shock wave / boundary layer interaction (SWBLI) at low Mach numbers to avoid a sudden drop in flow capture and engine thrust failure due to inlet actuation.

[0003] To address the challenge of inlet inertia at low speeds during flight over a wide speed range and mitigate hysteresis during restart, two main control strategies have been proposed. The first involves local flow control, which applies common flow control techniques such as suction, bulges, and vortex generators to the inlet compression section or throat, suppressing separation by weakening the SWBLI or adjusting local pressure gradients. The second involves geometric dynamic adjustment, which adapts the inlet configuration (such as the lip angle and throat area) to varying speed ranges.

[0004] However, existing methods still have limitations: flow control mostly targets a single interference factor, and it is difficult to coordinate the coupling effects of shock wave structure and geometric contraction. Summary of the Invention

[0005] In response to the above-mentioned deficiencies in the prior art, the present invention provides a control design method for improving the wide-range starting characteristics of the inlet duct, which solves the problem that the existing flow control mostly targets a single interference factor and is difficult to coordinate the coupling effect of the shock wave structure and geometric contraction.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is: a control design method for improving the wide-range starting characteristics of the intake duct, comprising the following steps:

[0007] S1: Acquire and store the numerical simulation flow field data of the intake duct;

[0008] S2: Based on the flow field data, analyze the flow field characteristics at different Mach numbers and determine the inlet non-starting range;

[0009] S3: Select the control device position based on the flow field characteristics;

[0010] S4: Based on the intake duct non-start range, verify the effectiveness of the control device and optimize the control parameters to complete the control design to improve the wide-range starting characteristics of the intake duct.

[0011] Furthermore, the S1 includes the following sub-steps:

[0012] S11: Establish the geometric model of the air intake and perform meshing;

[0013] S12: Configure the numerical solver and set the boundary conditions, physical model and numerical algorithm for the numerical simulation of the intake duct;

[0014] S13: Perform numerical simulation of the quasi-static acceleration and deceleration process of the inlet duct, and store the flow field data at different Mach numbers.

[0015] Furthermore, the step S2 includes the following sub-steps:

[0016] S21: Based on the flow field data at different Mach numbers, calculate the total pressure recovery coefficient of the outlet section corresponding to each Mach number state during quasi-static acceleration and deceleration;

[0017] S22: Draw a total pressure recovery coefficient-Mach number diagram based on the total pressure recovery coefficient of the outlet section;

[0018] S23: Based on a total pressure recovery coefficient-Mach number diagram, determine an inlet non-starting range by assigning a dual solution range corresponding to two different total pressure recovery coefficients for the same Mach number.

[0019] Furthermore, the total pressure recovery coefficient of the outlet section in S21 is for:

[0020]

[0021] in, is the average total pressure at the inlet duct outlet section, is the total pressure of the far-field incoming flow.

[0022] Furthermore, the step S3 includes the following sub-steps:

[0023] S31: Identify the shoulder separation zone location based on the Mach number cloud diagram of the flow field at different Mach numbers during the quasi-static acceleration and deceleration process of the inlet;

[0024] S32: Arrange a suction hole at the shoulder separation area, and set a wall deflection controller at the shoulder of the air inlet after the separation area.

[0025] Furthermore, the position of the shoulder separation zone in S31 is determined by identifying a subsonic region with a Mach number less than 1 near the inlet lip in the flow field.

[0026] Furthermore, in said S32 , pressure outlet boundary conditions are set for both the outlets of the suction hole and the wall deflection controller.

[0027] Furthermore, the S4 includes the following sub-steps:

[0028] S41: Based on the position of the wall deflection controller, repeat steps S1 and S2 to verify whether the inlet duct non-starting range is reduced to 0 after the control is applied within the given speed range, and whether the total pressure recovery coefficient of the outlet section is increased;

[0029] S42: If the control does not meet expectations, adjust the wall panel deflection angle and repeat steps S1 and S2 until the inlet duct non-starting range is reduced to 0 after control is applied within the given speed range, and the total pressure recovery coefficient of the outlet section is increased, completing the control design for improving the wide-range starting characteristics of the inlet duct.

[0030] The beneficial effects of the present invention are:

[0031] The present invention is widely applicable to the control problem of flow separation caused by shock wave boundary layer interference, such as the problem of non-startup at low Mach number in a wide-speed supersonic inlet.

[0032] The idea of ​​directly guiding the design of the controller position by analyzing the spatial flow field structure of the quasi-static acceleration process of the intake duct obtained by CFD is simple and efficient, and is a typical case of flow field characteristics guiding control design. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flow chart of a control design method for improving the wide-range starting characteristics of the intake duct according to the present invention.

[0034] Figure 2 Schematic diagram of a control design method for improving wide-range starting characteristics of an intake duct according to the present invention.

[0035] Figure 3 Comparison chart of the hysteresis loop of the total pressure recovery coefficient of the inlet duct of the original configuration.

[0036] Figure 4 Comparison of the hysteresis loop of the total pressure recovery coefficient of the inlet duct at different wall panel deflection angles.

[0037] Figure 5 This is a comparison chart of the control method's effect on suppressing intake shoulder separation. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0039] like Figure 1 and Figure 2 As shown, a control design method for improving the wide-range starting characteristics of the intake duct includes the following steps:

[0040] S1: Acquire and store the numerical simulation flow field data of the intake duct;

[0041] S2: Based on the flow field data, analyze the flow field characteristics at different Mach numbers and determine the inlet non-starting range;

[0042] S3: Select the control device position based on the flow field characteristics;

[0043] S4: Based on the intake duct non-start range, verify the effectiveness of the control device and optimize the control parameters to complete the control design to improve the wide-range starting characteristics of the intake duct.

[0044] The S1 includes the following steps:

[0045] S11: Establish the geometric model of the air intake and perform meshing;

[0046] S12: Configure the numerical solver and set the boundary conditions, physical model and numerical algorithm for the numerical simulation of the intake duct;

[0047] S13: Perform numerical simulation of the quasi-static acceleration and deceleration process of the inlet duct, and store the flow field data at different Mach numbers.

[0048] In this embodiment, numerical simulations are performed on the air inlet in the order of increasing the incoming flow Mach number from low to high / decreasing from high to low, and the flow field data are saved respectively.

[0049] The S2 includes the following steps:

[0050] S21: Based on the flow field data at different Mach numbers, calculate the total pressure recovery coefficient of the outlet section corresponding to each Mach number state during quasi-static acceleration and deceleration;

[0051] Before drawing the hysteresis loop of the performance parameters, the performance parameters at the inlet outlet need to be calculated first:

[0052] The total pressure recovery coefficient of the outlet section in S21 for:

[0053]

[0054] in, is the average total pressure at the inlet duct outlet section, is the total pressure of the far-field incoming flow;

[0055] S22: Draw a total pressure recovery coefficient-Mach number diagram based on the total pressure recovery coefficient of the outlet section, such as Figure 3 As shown;

[0056] S23: Based on a total pressure recovery coefficient-Mach number diagram, determine an inlet non-starting range by assigning a dual solution range corresponding to two different total pressure recovery coefficients for the same Mach number.

[0057] Figure 3 The interval where the same Mach number corresponds to two different total pressure recovery coefficients (double solution interval) is the inlet non-starting interval. Figure 3 The range in which the air intake does not start is determined to be Mach 2 to Mach 6.

[0058] The S3 includes the following sub-steps:

[0059] S31: Identify the shoulder separation zone location based on the Mach number cloud diagram of the flow field at different Mach numbers during the quasi-static acceleration and deceleration process of the inlet;

[0060] The position of the shoulder separation zone in S31 is determined by identifying a subsonic region with a Mach number less than 1 near the inlet lip in the flow field;

[0061] S32: Arrange a suction hole at the shoulder separation area, and set a wall deflection controller at the shoulder of the air inlet after the separation area;

[0062] In the above-mentioned S32, pressure outlet boundary conditions are set for the outlets of the suction hole and the wall deflection controller.

[0063] The S4 includes the following steps:

[0064] S41: Based on the position of the wall deflection controller, repeat steps S1 and S2 to verify whether the inlet duct non-starting range is reduced to 0 after the control is applied within the given speed range, and whether the total pressure recovery coefficient of the outlet section is increased;

[0065] After setting the position and parameters of the corresponding control device according to S3, repeat the steps of S1 and S2. The effectiveness of the control is judged based on the performance parameters of the controlled intake duct and its hysteresis loop. If the inert zone of the intake duct is reduced to 0 after the control is applied within the given speed range, and the total pressure recovery coefficient of the outlet section increases, the control design is considered effective.

[0066] S42: If the control does not meet expectations, adjust the wall panel deflection angle and repeat steps S1 and S2 until the inlet duct non-starting range is reduced to 0 after control is applied within the given speed range, and the total pressure recovery coefficient of the outlet section is increased, completing the control design for improving the wide-range starting characteristics of the inlet duct.

[0067] like Figure 4Figure 2 shows the total pressure recovery coefficient for different panel deflection angles of the inlet. It can be seen that after applying coordinated control, the total pressure recovery coefficient of the inlet is improved at every Mach number within the given speed range, and the hysteresis loop disappears when the panel deflection reaches 6°, indicating that the inlet achieves self-starting across a wide speed range and that the control design is effective. Further increasing the deflection angle beyond 6° does not result in significant total pressure recovery gains. Considering the flow loss, a 6° deflection is the preferred solution. Figure 5 The control method shows the effect of suppressing the shoulder separation of the intake duct under the condition of Ma=2, where (a) is the original configuration intake duct, and (b) is the intake duct using the control method of the present invention. The separation area of ​​the intake duct using the control method is significantly suppressed.

[0068] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the invention.

Claims

1. A control design method for improving the wide-range starting characteristics of the intake duct, characterized in that: The following steps are involved: S1: Acquire and store the numerical simulation flow field data of the intake duct; S2: Based on the flow field data, analyze the flow field characteristics at different Mach numbers and determine the inlet non-starting range; S3: Select the control device position based on the flow field characteristics; The S3 includes the following sub-steps: S31: Identify the shoulder separation zone location based on the Mach number cloud diagram of the flow field at different Mach numbers during the quasi-static acceleration and deceleration process of the inlet; The position of the shoulder separation zone in S31 is determined by identifying a subsonic region with a Mach number less than 1 near the inlet lip in the flow field; S32: Arrange a suction hole at the shoulder separation area, and set a wall deflection controller at the shoulder of the air inlet after the separation area; In said S32, pressure outlet boundary conditions are set at the outlets of the suction hole and the wall deflection controller; S4: Based on the intake manifold non-start range, verify the effectiveness of the control device and optimize the control parameters to complete the control design to improve the wide-range starting characteristics of the intake manifold; The S4 includes the following steps: S41: Based on the position of the wall deflection controller, repeat steps S1 and S2 to verify whether the inlet duct non-starting range is reduced to 0 after the control is applied within the given speed range, and whether the total pressure recovery coefficient of the outlet section is increased; S42: If the control does not meet expectations, adjust the wall panel deflection angle and repeat steps S1 and S2 until the inlet duct non-starting range is reduced to 0 after control is applied within the given speed range, and the total pressure recovery coefficient of the outlet section is increased, completing the control design for improving the wide-range starting characteristics of the inlet duct.

2. The control design method for improving the wide-range starting characteristics of the intake port according to claim 1, characterized in that: The S1 includes the following steps: S11: Establish the geometric model of the air intake and perform meshing; S12: Configure the numerical solver and set the boundary conditions, physical model and numerical algorithm for the numerical simulation of the intake duct; S13: Perform numerical simulation of the quasi-static acceleration and deceleration process of the inlet duct, and store the flow field data at different Mach numbers.

3. The control design method for improving the wide-range starting characteristics of the intake port according to claim 2, characterized in that: The S2 includes the following steps: S21: Based on the flow field data at different Mach numbers, calculate the total pressure recovery coefficient of the outlet section corresponding to each Mach number state during quasi-static acceleration and deceleration; S22: Draw a total pressure recovery coefficient-Mach number diagram based on the total pressure recovery coefficient of the outlet section; S23: Based on a total pressure recovery coefficient-Mach number diagram, determine an inlet non-starting range by assigning a dual solution range corresponding to two different total pressure recovery coefficients for the same Mach number.

4. The control design method for improving the wide-range starting characteristics of the intake port according to claim 3, characterized in that: The total pressure recovery coefficient of the outlet section in S21 for: ； in, is the average total pressure at the inlet duct outlet section, is the total pressure of the far-field incoming flow.

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