A method for regulating cabin pressure in high-altitude cabin pressure simulation calculation

Abstract

The present invention discloses a method for adjusting cabin pressure in a high-altitude cabin pressure simulation calculation, comprising the following steps: S1, establishing a joint simulation model of an aircraft engine, a high-altitude cabin, and an exhaust diffuser; S2, establishing a characteristic cross section for monitoring cabin pressure calculation results; S3, setting the initial boundary conditions of the exhaust diffuser outlet; S4, using a simulation calculation program to calculate the cabin pressure value corresponding to the current exhaust diffuser outlet pressure; S5, using an internal interpolation method, according to the current cabin pressure value, the exhaust diffuser outlet pressure value, and the target cabin pressure value, calculating the adjustment amount of the exhaust diffuser outlet pressure; S6, repeating steps S4 and S5 until the error between the current cabin pressure value and the target cabin pressure value is reduced to an acceptable range. The present invention solves the problems of low cabin pressure adjustment accuracy and low efficiency in existing high-altitude cabin pressure simulation calculations, and has the advantages of high accuracy, high efficiency, and automation.

Description

Technical Field

[0001] The invention belongs to the technical field of high-altitude simulation test equipment for aviation engines, and in particular relates to a cabin pressure regulating method in high-altitude cabin pressure simulation calculation. Background Art

[0002] High-altitude test chambers are ground-based aircraft engine testing equipment that enable engine performance parameters to be measured in artificially simulated high-altitude environments. High-altitude test chambers enable the evaluation and debugging of various aircraft engine performance parameters at different flight altitudes. The high-altitude test chamber's ability to simulate different flight altitudes relies on the regulation of the cabin pressure. The accuracy and efficiency of cabin pressure regulation determine the accuracy and efficiency of the simulation, necessitating the development of high-precision cabin pressure regulation methods.

[0003] With the development of computational fluid dynamics (CFD) technology, computer simulation has become an important means of studying complex flow fields. In the simulation of the flow field inside a high-altitude cabin, the accuracy of the cabin pressure regulation directly determines the reliability and stability of the simulation results. Summary of the Invention

[0004] Purpose of the invention: The present invention provides a cabin pressure regulation method in high-altitude cabin pressure simulation calculation, which can effectively improve the accuracy and efficiency of cabin pressure regulation.

[0005] Technical solution: The present invention provides a method for adjusting cabin pressure in a high-altitude cabin pressure simulation calculation, which specifically includes the following steps:

[0006] S1. Establish a joint simulation model of the aircraft engine, high-altitude cabin, and exhaust diffuser;

[0007] S2. Establish a characteristic section for monitoring cabin pressure calculation results;

[0008] S3. Setting the initial boundary conditions of the exhaust diffuser outlet;

[0009] S4. Using a simulation calculation program, calculate the cabin pressure value corresponding to the current exhaust diffuser outlet pressure;

[0010] S5. Calculating an adjustment amount for the exhaust diffuser outlet pressure based on the current cabin pressure value, the exhaust diffuser outlet pressure value, and the target cabin pressure value using an internal interpolation method;

[0011] S6. Repeat steps S4 and S5 until the error between the current cabin pressure value and the target cabin pressure value is reduced to a preset range.

[0012] Furthermore, the characteristic cross section described in step S2 is tangent to the engine outlet cross section, the surface normal of the characteristic cross section is consistent with the axis direction of the high-altitude cabin, the distance between the outer edge line of the characteristic cross section and the surface normal of the high-altitude cabin wall is greater than the wall boundary layer thickness, and the distance between the inner edge line and the wall normal of the aircraft engine is greater than the wall boundary layer thickness.

[0013] Furthermore, the type of the exhaust diffuser outlet boundary condition in step S3 is a pressure outlet, and the pressure values ​​of the initial boundary conditions are 1 times and 1.2 times the target cabin pressure value.

[0014] Furthermore, the cabin pressure value described in step S4 is the surface average value of the pressure on the characteristic cross section.

[0015] Furthermore, the implementation process of step S5 is as follows:

[0016] Initially, the actual cabin pressure value calculated when the exhaust diffuser outlet pressure is equal to 1 times the target cabin pressure is recorded as y A At this time, the exhaust diffuser outlet pressure value is recorded as x A The actual cabin pressure value calculated when the exhaust diffuser outlet pressure is equal to 1.2 times the target cabin pressure is recorded as y B At this time, the exhaust diffuser outlet pressure value is recorded as x B , the target cabin pressure value is recorded as y ideal ;

[0017] When the cabin pressure value y calculated in step S4 is ≤ y ideal When y A Equal to the cabin pressure value at this time, let x A Equal to the exhaust diffuser outlet pressure value at this time; when the cabin pressure value y calculated in step S4>y ideal When y B Equal to the cabin pressure value at this time, let x B Equal to the exhaust diffuser outlet pressure value at this time; according to the equation Solve for the adjustment amount x of the exhaust diffuser outlet pressure.

[0018] Furthermore, the normal distance between the outer edge line of the characteristic section and the high-altitude cabin wall surface is 100 mm, and the normal distance between the inner edge line and the aircraft engine wall surface is 100 mm.

[0019] Beneficial effects: Compared with the existing technology, the beneficial effects of the present invention: The present invention solves the problems of low cabin pressure adjustment accuracy and low efficiency in the existing high-altitude cabin pressure simulation calculation, and has the advantages of high accuracy, high efficiency and automation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flow chart of the present invention;

[0021] Figure 2 This is a schematic structural diagram of a joint simulation model of an aircraft engine, a high-altitude cabin, and an exhaust diffuser applicable to the present invention;

[0022] Figure 3 A schematic diagram of the position and shape of the characteristic cross section for monitoring cabin pressure calculation results established in the present invention;

[0023] Figure 4 This is a schematic diagram showing how the actual cabin pressure in the cabin gradually approaches the target cabin pressure using the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings.

[0025] The embodiment of the present invention provides a method for adjusting cabin pressure in a high altitude cabin pressure simulation calculation, such as Figure 1 As shown, the following steps are included:

[0026] S1. Establish a joint simulation model of the aircraft engine, high-altitude cabin, and exhaust diffuser, such as Figure 2 As shown, the model includes three components: engine, high-altitude cabin, and exhaust diffuser. A baffle is provided at the bottom of the high-altitude cabin, and a secondary flow inlet is provided at the front of the high-altitude cabin.

[0027] S2. Establish characteristic sections for monitoring cabin pressure calculation results, such as Figure 3 As shown, the cross section is tangent to the engine outlet cross section, the cross section's surface normal is aligned with the axis of the high-altitude compartment, the outer edge of the characteristic cross section's surface normal distance from the high-altitude compartment wall is greater than the wall boundary layer thickness, and the inner edge of the characteristic cross section's surface normal distance from the aircraft engine wall is greater than the wall boundary layer thickness. In this embodiment, the outer edge of the cross section's surface normal distance from the high-altitude compartment wall is 100 mm, and the inner edge of the cross section's surface normal distance from the aircraft engine wall is 100 mm.

[0028] S3. Set the initial boundary condition for the exhaust diffuser outlet. The type of the exhaust diffuser outlet boundary condition is pressure outlet. The pressure values ​​of the initial boundary condition are 1 times and 1.2 times the target cabin pressure value.

[0029] S4. Using a simulation program, calculate a cabin pressure value corresponding to the current exhaust diffuser outlet pressure. The cabin pressure value is equal to the average pressure value on the characteristic cross section for monitoring cabin pressure according to claim 1.

[0030] S5. Calculating the adjustment amount of the exhaust diffuser outlet pressure based on the current cabin pressure value, the exhaust diffuser outlet pressure value, and the target cabin pressure value using an internal interpolation method, specifically comprising the following steps:

[0031] Initially, the actual cabin pressure value calculated when the exhaust diffuser outlet pressure is equal to 1 times the target cabin pressure is recorded as x A The exhaust diffuser outlet pressure at this time is recorded as y A The actual cabin pressure calculated when the exhaust diffuser outlet pressure is equal to 1.2 times the target cabin pressure is recorded as x B The exhaust diffuser outlet pressure at this time is recorded as y B , draw a function curve of cabin pressure with respect to exhaust diffuser outlet pressure, such as Figure 4 shown.

[0032] The target cabin pressure value is recorded as y ideal , when the cabin pressure value y calculated in the previous step is ≤y ideal When y A Equal to the cabin pressure value at this time, let x A Equal to the exhaust diffuser outlet pressure value at this time, when the cabin pressure value y calculated in the previous step>y ideal When y B Equal to the cabin pressure value at this time, let x B It is equal to the exhaust diffuser outlet pressure value at this time.

[0033] According to the equation Solve for the adjustment amount x of the exhaust diffuser outlet pressure.

[0034] S6. Repeat steps S4 and S5 until the error between the current cabin pressure value and the target cabin pressure value is reduced to an acceptable range, which specifically includes the following steps:

[0035] Repeat step S4 for the first time. Based on the current exhaust diffuser outlet pressure value x, use the calculation program to calculate the cabin pressure value y corresponding to the current exhaust diffuser outlet pressure. Point C1 can be drawn with (x, y) as the coordinates, as shown in the following example: Figure 4 shown.

[0036] The first time step S5 is repeated, since the calculated y≤y ideal , let y A Equal to the cabin pressure value at this time, let x A Equal to the exhaust diffuser outlet pressure value at this time. According to the equation Solve for the adjustment amount x of the exhaust diffuser outlet pressure.

[0037] Since the cabin pressure error at this time is higher than the required range of 0.05%, step S4 is repeated for the second time. Based on the current exhaust diffuser outlet pressure value x, the calculation program is used to calculate the cabin pressure value y corresponding to the current exhaust diffuser outlet pressure. Point C2 can be drawn with (x, y) as the coordinates, as shown in the following example: Figure 4shown.

[0038] Repeat step S5 for the second time. Since the calculated y≤y ideal , let y A Equal to the cabin pressure value at this time, let x A Equal to the exhaust diffuser outlet pressure value at this time. According to the equation Solve for the adjustment amount x of the exhaust diffuser outlet pressure.

[0039] Since the cabin pressure error at this time is higher than the required range of 0.05%, step S4 is repeated for the third time. Based on the current exhaust diffuser outlet pressure value x, the calculation program is used to calculate the cabin pressure value y corresponding to the current exhaust diffuser outlet pressure. Point C3 can be drawn with (x, y) as the coordinates, as shown in the following example: Figure 4 As shown; In addition, C goal Point coordinates (x goal ,y goal ), x goal In order to obtain the cabin pressure value, y goal Indicates the cabin pressure value you want to obtain through adjustment and the exhaust diffuser outlet value you need to set.

[0040] Step S5 is repeated for the third time. Since the calculated actual cabin pressure value y is different from the target cabin pressure value y ideal The error has met the technical requirement of less than or equal to 0.05%, and step 6 is stopped. After the above steps, the error between the cabin pressure value in the high-altitude cabin and the target cabin pressure value is less than 0.05%, and high-precision and efficient adjustment of the cabin pressure has been achieved.

Claims

1. A method for regulating cabin pressure in a high-altitude cabin pressure simulation calculation, characterized in that: The following steps are involved: S1. Establish a joint simulation model of the aircraft engine, high-altitude cabin, and exhaust diffuser; S2. Establish a characteristic section for monitoring cabin pressure calculation results; S3. Setting the initial boundary conditions of the exhaust diffuser outlet; S4. Using a simulation calculation program, calculate the cabin pressure value corresponding to the current exhaust diffuser outlet pressure; S5. Calculating an adjustment amount for the exhaust diffuser outlet pressure based on the current cabin pressure value, the exhaust diffuser outlet pressure value, and the target cabin pressure value using an internal interpolation method; S6, repeating steps S4 and S5 until the error between the current cabin pressure value and the target cabin pressure value is reduced to a preset range; The implementation process of step S5 is as follows: Initially, the actual cabin pressure value calculated when the exhaust diffuser outlet pressure is equal to 1 times the target cabin pressure is recorded as y A At this time, the exhaust diffuser outlet pressure value is recorded as x A The actual cabin pressure value calculated when the exhaust diffuser outlet pressure is equal to 1.2 times the target cabin pressure is recorded as y B At this time, the exhaust diffuser outlet pressure value is recorded as x B , the target cabin pressure value is recorded as y ideal ; When the cabin pressure value y calculated in step S4 is ≤ y ideal When y A Equal to the cabin pressure value at this time, let x A Equal to the exhaust diffuser outlet pressure value at this time; when the cabin pressure value y calculated in step S4>y ideal When y B Equal to the cabin pressure value at this time, let x B Equal to the exhaust diffuser outlet pressure value at this time; according to the equation Solve for the adjustment amount x of the exhaust diffuser outlet pressure.

2. The method for adjusting cabin pressure in high-altitude cabin pressure simulation calculation according to claim 1, characterized in that: The characteristic cross section described in step S2 is tangent to the engine outlet cross section, the surface normal of the characteristic cross section is consistent with the axis direction of the high-altitude cabin, the distance between the outer edge line of the characteristic cross section and the surface normal of the high-altitude cabin wall is greater than the wall boundary layer thickness, and the distance between the inner edge line and the aircraft engine wall surface is greater than the wall boundary layer thickness.

3. The method for adjusting cabin pressure in high-altitude cabin pressure simulation calculation according to claim 1, characterized in that: The type of the exhaust diffuser outlet boundary condition described in step S3 is a pressure outlet, and the pressure values ​​of the initial boundary conditions are 1 times and 1.2 times the target cabin pressure value.

4. The method for adjusting cabin pressure in high-altitude cabin pressure simulation calculation according to claim 1, characterized in that: The cabin pressure value described in step S4 is the surface average value of the pressure on the characteristic cross section.

5. The method for adjusting cabin pressure in high-altitude cabin pressure simulation calculation according to claim 2, characterized in that: The normal distance between the outer edge line of the characteristic section and the high-altitude cabin wall surface is 100 mm, and the normal distance between the inner edge line and the aircraft engine wall surface is 100 mm.

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