Hypersonic aircraft ventilation system and design method thereof

Abstract

The invention provides a hypersonic aircraft ventilation system and a design method thereof. The method comprises the following steps: acquiring an aircraft trajectory and an aircraft mathematical model; partitioning the model structure of the aircraft digital model, and calculating external pressure values of different partitions according to trajectory parameters determined by the trajectory of the aircraft; carrying out one-dimensional isentropic calculation according to the external pressure values of different partitions and given initial parameters to obtain initial result parameters under initial conditions in the flight process; the initial result parameters serve as input, CFD simulation first iterative calculation is carried out, ventilation coefficients of ballistic feature points are obtained, the ventilation coefficients K, obtained through CFD simulation first iterative calculation, of the ballistic feature points and the ventilation area under the current condition serve as input, one-dimensional isentropic calculation is carried out, and internal pressure and internal and external pressure difference data under the current condition are obtained. The ventilation position and the ventilation area range of the ventilation system can be rapidly determined, the internal and external pressure difference in the flight process of the aircraft is accurately iterated, and the design efficiency and accuracy are improved.

Description

Technical Field

[0001] The present application relates to the technical field of aircraft ventilation systems, and in particular to a hypersonic aircraft ventilation system and a design method thereof. Background Art

[0002] The launch vehicle consists of multiple compartments. During its ascent, the external environment changes drastically. The external pressure drops sharply in a short period of time as the altitude increases. However, the internal pressure drops relatively slowly, resulting in a significant pressure difference. In view of this, vents are usually set in each compartment to reduce the internal and external pressure differential load of the rocket body.

[0003] Reentry vehicles generally adopt a closed cabin structure layout. During the reentry process, the external environmental pressure will increase rapidly in a short period of time. When the natural gaps of the vehicle cannot be known in advance, by designing reasonable vents at appropriate positions on the vehicle surface, the cabin pressure can change synchronously with the external environmental pressure. This is an effective way to reduce the pressure differential load inside and outside the vehicle.

[0004] The ventilation system of the launch vehicle is mainly concentrated in the fairing column section, and the ventilation system of the reentry vehicle is located on the leeward side. The opening position of the vents is often determined by the designer's experience.

[0005] During flight, the external environment of the aircraft changes dramatically, and this change can cause the ventilation system to face an environmental pressure that is inconsistent with design expectations. As a result, the ventilation system's efficiency is reduced, and in severe cases, the aircraft may be damaged. For example, during the re-entry phase, if the environmental pressure far exceeds the design value, it may cause poor ventilation and abnormal increase in internal pressure, posing a threat to the aircraft structure.

[0006] Conventional ventilation systems have shortcomings. Their ventilation area is fixed and their design method is idealized. This causes a deviation between the calculated internal and external pressure differential load and the actual flight data. To ensure flight safety, a larger safety margin can only be added. However, doing so will increase the weight and cost of the aircraft, and the ability to carry payload will also be reduced accordingly.

[0007] Therefore, the technical problem that needs to be solved urgently is: how to provide a hypersonic aircraft ventilation system and its design method, which can quickly determine the ventilation position and ventilation area range of the ventilation system, accurately iterate the internal and external pressure difference during the flight of the aircraft, and improve the design efficiency and accuracy. At the same time, under the premise of ensuring the strength of the aircraft, effectively reduce the pressure difference load, reduce the design redundancy caused by the large pressure difference design error, reduce the weight of the aircraft, and improve the carrying capacity of the aircraft. Summary of the invention

[0008] The purpose of this application is to provide a hypersonic aircraft ventilation system and a design method thereof, which can quickly determine the ventilation position and ventilation area range of the ventilation system, accurately iterate the internal and external pressure difference during the flight of the aircraft, and improve the design efficiency and accuracy. At the same time, under the premise of ensuring the strength of the aircraft, the pressure difference load is effectively reduced, the design redundancy caused by the large pressure difference design error is reduced, the weight of the aircraft is reduced, and the carrying capacity of the aircraft is improved.

[0009] To achieve the above-mentioned purpose, the present application provides a design method for a ventilation system of a hypersonic aircraft, the method comprising the following steps: obtaining an aircraft trajectory and an aircraft digital model; partitioning the model structure of the aircraft digital model, and performing CFD simulation calculations according to the ballistic parameters determined by the aircraft trajectory to obtain external pressure values ​​of different partitions; performing one-dimensional isentropic calculations according to the external pressure values ​​of different partitions and given initial parameters to obtain initial result parameters under initial conditions during flight, wherein the initial result parameters include internal and external pressure values ​​and ventilation area ranges under different ventilation position conditions; using the initial result parameters as input, performing a first iteration of CFD simulation calculations to obtain Ventilation coefficient K at the trajectory feature point; take the ventilation coefficient K at the trajectory feature point obtained by the first iterative calculation of CFD simulation and the ventilation area under the current conditions as input, carry out one-dimensional isentropic calculation, and obtain the internal pressure and internal and external pressure difference data under the current conditions; judge whether the internal pressure and internal and external pressure difference data under the current conditions meet the constraints, if not, reselect the ventilation position and ventilation area, re-perform CFD simulation iterative calculation, obtain the updated ventilation coefficient K, and repeat this step until the internal pressure and internal and external pressure difference data under the current conditions meet the constraints, and obtain the ventilation position, ventilation area, internal pressure and internal and external pressure difference data that meet the constraints.

[0010] The design method of the ventilation system of a hypersonic aircraft as described above, wherein a one-dimensional isentropic calculation is performed according to the external pressure values ​​of different partitions and given initial parameters to obtain the initial result parameters under the initial conditions during the flight process, including: setting the aircraft pressure difference load range as a constraint condition; performing the first iterative calculation process of the one-dimensional isentropic calculation according to the external pressure values ​​of different partitions and a given initialization ventilation coefficient as an initial iteration value to obtain the internal and external pressure values ​​and the initial ventilation area under different ventilation position conditions.

[0011] In the design method of the ventilation system of a hypersonic vehicle as described above, the calculation formula of the ventilation coefficient of the trajectory characteristic point is:

[0012]

[0013] Among them, Q cfd is the ventilation flow value obtained by CFD simulation; Q gis the ventilation flow value calculated by the one-dimensional isentropic calculation formula; K is the ventilation coefficient of the trajectory characteristic point.

[0014] In the design method of the ventilation system of a hypersonic aircraft as described above, the one-dimensional isentropic calculation formula is as follows:

[0015]

[0016] Among them, Q g represents ventilation flow; S represents ventilation area; γ represents specific heat ratio; P D is the downstream pressure; R is the gas constant; T U Represents the upstream temperature; Ma is a parameter.

[0017] The design method of the ventilation system of a hypersonic aircraft as described above, wherein:

[0018] Among them, P U and P D are the upstream pressure and downstream pressure respectively; γ represents the specific heat ratio.

[0019] In the design method of the ventilation system of a hypersonic aircraft as described above, the ventilation area S in the one-dimensional isentropic calculation formula is a given estimated value and is modified through iteration.

[0020] In the design method of the ventilation system of a hypersonic vehicle as described above, in the ascent phase of the rocket, the upstream pressure refers to the internal pressure value of the vehicle; and the downstream pressure refers to the external pressure value of the vehicle.

[0021] The design method of the ventilation system of a hypersonic aircraft as described above, wherein the process of one-dimensional isentropic calculation includes: according to the known external pressure value, the gas mass loss at the current moment is obtained by time difference calculation; according to the ideal gas state equation and the gas mass loss, the density and pressure of the gas in the cabin after the loss are solved; the solved density and pressure are substituted into the calculation formula of the ideal gas state equation at the next moment, and it is repeated to obtain the internal pressure value and the internal and external pressure difference that change with time.

[0022] In the design method of the ventilation system of a hypersonic aircraft as described above, the one-dimensional isentropic calculation process further includes: solving the change of Ma over time based on the internal pressure value and the external pressure value.

[0023] As a second aspect of the present application, the present application provides a hypersonic aircraft ventilation system, which is obtained by the design method of the hypersonic aircraft ventilation system, and the system includes: an aircraft and a vent; the vent is arranged on the cabin of the aircraft, and the ventilation area range and ventilation position of the vent are obtained according to the design method of the hypersonic aircraft ventilation system.

[0024] The beneficial effects achieved by this application are as follows:

[0025] (1) The present application improves the efficiency of determining the ventilation position and ventilation area range of the ventilation system, so that the internal and external pressure difference of the aircraft during iterative flight is closer to the actual flight value, thereby improving design efficiency and accuracy.

[0026] (2) Under the premise of ensuring the strength of the aircraft, this application effectively reduces the pressure difference load, reduces the design redundancy caused by large errors in pressure difference calculation, reduces the weight of the aircraft, and improves the carrying capacity of the aircraft.

[0027] (3) The present application ensures that the pressure change distribution inside the reentry vehicle is reasonable, reduces the pressure differential load during the reentry phase, and ensures that the internal load of the vehicle will not be damaged by the impact of the pressure differential load. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For those skilled in the art, other drawings can also be obtained based on these drawings.

[0029] Figure 1 This is a schematic diagram of the digital model structure of an aircraft according to an embodiment of the present application.

[0030] Figure 2 The process of a design method of a hypersonic aircraft ventilation system according to an embodiment of the present application is as follows: Figure 1 .

[0031] Figure 3 The process of a design method of a hypersonic aircraft ventilation system according to an embodiment of the present application is as follows: Figure 2

[0032] Reference numerals: 1 - aircraft; 11 - separation area. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0034] Embodiment 1

[0035] like Figure 1 and 3 As shown, the present application provides a design method for a hypersonic aircraft ventilation system, the method comprising the following steps:

[0036] Step S1, obtaining the aircraft trajectory and the aircraft digital model.

[0037] Among them, the aircraft trajectory is used to calculate the external pressure value distributed on the aircraft surface on the one hand, and on the other hand as an input parameter for one-dimensional isentropic calculation.

[0038] It should be explained that the trajectory of an aircraft includes the trajectory parameters of the aircraft during flight, such as flight altitude, flight speed, attitude angle, etc. Through these key information, the parameters of the atmospheric environment at each position of the aircraft can be determined, such as the atmospheric density, pressure and temperature corresponding to different altitudes. These parameters, combined with the flight attitude, can be input into the CFD (computational fluid dynamics) simulation calculation as boundary conditions, and then simulate the flow field around the aircraft, and finally obtain the distributed external pressure value on the aircraft surface.

[0039] It should be explained that the ballistic parameters (such as flight altitude and flight speed) given by the aircraft trajectory can be used for some initial or boundary conditions of one-dimensional isentropic calculation. For example, the local atmospheric pressure and density can be obtained according to the flight altitude as the basic state parameters of one-dimensional isentropic calculation.

[0040] Step S2, partitioning the model structure of the aircraft digital model, and calculating the external pressure values ​​of different partitions according to the ballistic parameters determined by the aircraft trajectory.

[0041] like Figure 2 As shown, the model structure of the aircraft digital model is partitioned to obtain different separated areas 11. The aircraft 1 is provided with a plurality of separated areas 11 spaced apart in a direction perpendicular to its axis. According to CFD (computational fluid dynamics) simulation calculation, the external pressure values ​​of different partitions (separated areas) are obtained. The present application implements the partitioning operation based on the digital model structure to ensure the accuracy of the calculation of the distributed external pressure value. The characteristics of the digital model structure are deeply analyzed, and the partitioning criteria and methods are determined based on the physical characteristics and geometric morphology. At the same time, the consistency of the entire digital model system is ensured.

[0042] As a specific embodiment of the present invention, the atmospheric density, pressure, temperature and other parameters corresponding to different altitudes determined by the trajectory of the aircraft are input into the CFD (computational fluid dynamics) simulation calculation as boundary conditions in combination with the flight attitude, thereby simulating the flow field around the aircraft, and finally obtaining the distributed external pressure value on the aircraft surface. The obtained distributed external pressure value on the aircraft surface is used as the input condition for the subsequent one-dimensional isentropic calculation.

[0043] Step S3, performing one-dimensional isentropic calculation according to the external pressure values ​​of different partitions and the given initial parameters, and obtaining the initial result parameters under the initial conditions during the flight process.

[0044] The initial result parameters include the initial ventilation area and internal and external pressure values ​​under different ventilation position conditions.

[0045] Specifically, one-dimensional isentropic calculation is carried out according to the external pressure values ​​of different partitions and the given initial parameters to obtain the initial ventilation area, internal pressure value and external pressure value under different ventilation position conditions.

[0046] Specifically, the application uses the input distributed external pressure value and ballistic parameters as input quantities to start a one-dimensional isentropic calculation process. In this process, according to a specific pressure differential load range [ΔPmin, ΔPmax], through rigorous calculation and analysis, the corresponding internal and external pressure values ​​and ventilation area are derived, thereby improving the calculation accuracy of the internal and external pressure values ​​and ventilation area.

[0047] Step S3 includes:

[0048] Step S310, setting the aircraft pressure differential load range as a constraint condition.

[0049] Step S320, based on the external pressure values ​​of different partitions and a given initial ventilation coefficient as an initial iteration value, a first iteration calculation process of one-dimensional isentropic calculation is carried out to obtain the initial ventilation area and internal and external pressure values ​​under different ventilation position conditions.

[0050] Specifically, the aircraft pressure differential load range [ΔPmin, ΔPmax] is set as a constraint condition, the initialization ventilation coefficient K is given as the initial iteration value, and a one-dimensional isentropic calculation is carried out.

[0051] Among them, the one-dimensional isentropic calculation formula is as follows:

[0052]

[0053] in,

[0054] Among them, Q g represents ventilation flow; S represents ventilation area; γ represents specific heat ratio; P U and P Dare the upstream pressure and the downstream pressure respectively; R represents the gas constant; T U Represents the upstream temperature; Ma is a parameter.

[0055] The upstream pressure P U Refers to the pressure on the side with greater pressure, the downstream pressure P D Refers to the pressure on the side with smaller pressure. Taking the ascent stage of a rocket as an example, the upstream pressure refers to the internal pressure value (internal pressure value), and the downstream pressure refers to the external pressure (external pressure value). When the aircraft is a return capsule, on the contrary, the upstream pressure refers to the external pressure, and the downstream pressure refers to the internal pressure. The upstream and downstream definitions of temperature are the same as those of pressure. Taking the ascent stage of a rocket as an example, the upstream temperature refers to the internal temperature of the aircraft. When the aircraft is a return capsule, the upstream temperature refers to the external temperature of the aircraft.

[0056] Among them, Q G is the value obtained by the above formula. In the simulation of the rocket ascent, in the above one-dimensional isentropic calculation formula, P D is the external pressure value (related to time) obtained by CFD (Computational Fluid Dynamics) simulation calculation. The ventilation area S is a given estimated value, which is subsequently modified by iteration. Preferably, the ventilation area is modified within a given range of values.

[0057] As a specific embodiment of the present invention, taking the rocket ascent stage as an example, the process of one-dimensional isentropic calculation of the present invention is:

[0058] Step T1, giving an initial ground pressure.

[0059] Step T2, based on the known external pressure value, calculate the gas mass loss at the current moment through time term difference. The time term difference calculation method is: Wherein, Δm represents the gas mass loss; C d represents the flow coefficient; A represents the leakage area; Δt represents the time interval; ρ in Indicates the gas density in the cabin; P in Indicates the gas pressure in the cabin; P out Indicates the gas pressure outside the cabin.

[0060] Step T3, according to the ideal gas state equation and the gas mass loss, solve the density and pressure of the gas in the cabin after the loss. The calculation formula of the density after the loss is: m1 is the mass of the gas in the cabin at the initial state; V is the volume of the rocket cabin. The formula for calculating the pressure after the loss is: R represents the universal gas constant; T represents temperature; M represents the molar mass of the gas; and V represents the volume of the rocket cabin.

[0061] Step T4, substitute the solved density and pressure into the ideal gas state equation calculation formula at the next moment, iterate repeatedly, and obtain the internal pressure value and internal and external pressure difference that change with time. The ideal gas state equation is: Among them, P0 represents the initial pressure; V represents the volume of the rocket cabin; m0 represents the initial mass of the gas in the rocket cabin; R represents the universal gas constant; T0 represents the initial temperature; ρ0 represents the initial density. The calculation formula for the initial internal and external pressure difference is: ΔP0=P0-P out ; Among them, P out is the known pressure outside the cabin.

[0062] Step T5, according to the internal pressure value (ie, upstream pressure) and the external pressure value (ie, downstream pressure), solve the change of Ma with time.

[0063] Step S4, taking the initial result parameters as input, performing the first iteration calculation of the CFD simulation, and obtaining the ventilation coefficient K at the trajectory feature point.

[0064] As a specific embodiment of the present invention, the initial ventilation area and internal pressure value obtained by one-dimensional isentropic calculation are used as input, and CFD simulation calculation is used to obtain the ventilation coefficient of the trajectory characteristic point. The CFD simulation calculation used in this application is an existing simulation calculation method and will not be repeated here.

[0065] Among them, the calculation formula of the ventilation coefficient of the trajectory characteristic point is:

[0066]

[0067] Among them, Q cfd is the ventilation flow value obtained by CFD simulation; Q g is the ventilation flow value calculated by the above one-dimensional isentropic calculation formula; K is the ventilation coefficient of the trajectory characteristic point.

[0068] Step S5, taking the ventilation coefficient K of the trajectory feature point obtained by the first iteration calculation of the CFD simulation and the ventilation area under the current conditions as input, performing a one-dimensional isentropic calculation to obtain the internal pressure and internal and external pressure difference data under the current conditions.

[0069] Among them, Q can be calculated by substituting the ventilation coefficient K of the trajectory characteristic point and the external pressure data in the initial parameters into the one-dimensional isentropic equation: g .

[0070] Among them, the one-dimensional isentropic calculation formula is as follows:

[0071]

[0072] in,

[0073] Among them, Qg represents ventilation flow; S represents ventilation area; γ represents specific heat ratio; P U and P D are the upstream pressure and the downstream pressure respectively; R represents the gas constant; T U Represents the upstream temperature; Ma is a parameter.

[0074] The ventilation area S is an estimated value set under current conditions.

[0075] As a specific embodiment of the present invention, in the rocket ascending stage, the external pressure is used as the downstream pressure, the ventilation area S is set, and the ventilation coefficient K and other parameters of the trajectory characteristic point are input into the one-dimensional isentropic calculation formula, and the obtained upstream pressure is the internal pressure. The difference between the internal pressure and the external pressure is calculated as the internal and external pressure difference data.

[0076] Step S6, determine whether the internal pressure and the internal-external pressure difference data under the current conditions meet the constraints. If the constraints are not met, reselect the ventilation position and ventilation area, re-perform CFD simulation iterative calculation, obtain the updated ventilation coefficient K, and repeat this step until the internal pressure and the internal-external pressure difference data under the current conditions meet the constraints, and obtain the ventilation position, ventilation area, internal pressure and internal-external pressure difference data that meet the constraints.

[0077] Among them, the constraint condition is the aircraft pressure difference load range [ΔPmin, ΔPmax].

[0078] As a specific embodiment of the present invention, the ventilation coefficient of the obtained trajectory characteristic point and the ventilation area under corresponding conditions are used as input, and one-dimensional isentropic calculation is used to obtain the internal and external pressure values ​​within the pressure differential load range of the aircraft.

[0079] The internal and external pressure values ​​include the internal pressure value and the external pressure value of the aircraft.

[0080] As a specific embodiment of the present invention, it is determined whether the internal pressure and the internal and external pressure difference data under the current conditions meet the constraints. If the internal pressure and the internal and external pressure difference data under the current conditions do not meet the constraints, the ventilation position and ventilation area are reselected. If the ventilation area range changes, the CFD simulation iteration calculation is started again, the ventilation coefficient K of the trajectory feature point is recalculated, and the ventilation coefficient K of the recalculated trajectory feature point and the ventilation area under the current conditions are used as inputs to carry out one-dimensional isentropic calculation to obtain the internal pressure and the internal and external pressure difference data under the current conditions. And repeat the current step until the internal pressure and the internal and external pressure difference data under the current conditions meet the constraints before stopping the current step. If the internal pressure and the internal and external pressure difference data under the current conditions meet the constraints, there is no need to reselect the ventilation position and ventilation area, and the ventilation position, ventilation area, internal pressure and internal and external pressure difference data that meet the constraints are output. The ventilation area and internal and external pressure values ​​that meet the aircraft pressure difference load range are obtained. It can be understood that if the ventilation area range does not change (or is no longer modified), the internal and external pressure data, the ventilation area range and the ventilation position are output.

[0081] The internal and external pressure data include the internal and external pressure values ​​of the aircraft.

[0082] As a specific embodiment of the present invention, the simulation calculation accuracy is evaluated according to the ventilation area and the internal and external pressures, and the ventilation coefficient is calculated unsteadily and iteratively coupled with a one-dimensional isentropic calculation program to improve the calculation accuracy.

[0083] Embodiment 2

[0084] The present application provides a hypersonic aircraft ventilation system, which is obtained by the design method of the hypersonic aircraft ventilation system described in Example 1. The system includes: an aircraft and a vent; the vent is arranged on the cabin of the aircraft, and the ventilation area range and ventilation position of the vent are obtained according to the design method of the hypersonic aircraft ventilation system.

[0085] The beneficial effects achieved by this application are as follows:

[0086] (1) The present application improves the efficiency of determining the ventilation position and ventilation area range of the ventilation system, so that the internal and external pressure difference of the aircraft during iterative flight is closer to the actual flight value, thereby improving design efficiency and accuracy.

[0087] (2) Under the premise of ensuring the strength of the aircraft, this application effectively reduces the pressure difference load, reduces the design redundancy caused by large errors in pressure difference calculation, reduces the weight of the aircraft, and improves the carrying capacity of the aircraft.

[0088] (3) The present application ensures that the pressure change distribution inside the reentry vehicle is reasonable, reduces the pressure differential load during the reentry phase, and ensures that the internal load of the vehicle will not be damaged by the impact of the pressure differential load.

[0089] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0090] In the description of the present application, the word "for example" is used to mean "used as an example, illustration or explanation". Any embodiment described as "for example" in the present application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is given to enable any technician in the field to implement and use the present invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid obscuring the description of the present invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in the present application.

[0091] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for designing a ventilation system for a hypersonic vehicle, characterized in that: The method comprises the following steps: Obtain aircraft trajectory and aircraft digital model; The model structure of the aircraft digital model is partitioned, and CFD simulation calculations are performed based on the ballistic parameters determined by the aircraft trajectory to obtain the external pressure values ​​of different partitions; According to the external pressure values ​​of different partitions and the given initial parameters, one-dimensional isentropic calculation is carried out to obtain the initial result parameters under the initial conditions during the flight process, wherein the initial result parameters include the internal and external pressure values ​​and the ventilation area range under different ventilation position conditions; The initial result parameters are used as input to perform the first iteration of CFD simulation to obtain the ventilation coefficient K at the trajectory feature point; The ventilation coefficient K of the trajectory feature point obtained by the first iteration of CFD simulation and the ventilation area under the current conditions are used as input to carry out one-dimensional isentropic calculation to obtain the internal pressure and internal and external pressure difference data under the current conditions; Determine whether the internal pressure and internal-external pressure difference data under the current conditions meet the constraints. If they do not meet the constraints, reselect the ventilation position and ventilation area, re-perform CFD simulation iterative calculation, and obtain the updated ventilation coefficient K. Repeat this step until the internal pressure and internal-external pressure difference data under the current conditions meet the constraints, and obtain the ventilation position, ventilation area, internal pressure and internal-external pressure difference data that meet the constraints.

2. The method for designing a ventilation system for a hypersonic vehicle according to claim 1, characterized in that: According to the external pressure values ​​of different partitions and the given initial parameters, one-dimensional isentropic calculation is carried out, and the initial result parameters under the initial conditions during the flight process are obtained, including: The aircraft pressure differential load range is set as a constraint condition; According to the external pressure values ​​of different partitions and the given initial ventilation coefficient as the initial iteration value, the first iteration calculation process of one-dimensional isentropic calculation is carried out to obtain the internal and external pressure values ​​and the initial ventilation area under different ventilation position conditions.

3. The method for designing a ventilation system for a hypersonic vehicle according to claim 1, characterized in that: The calculation formula of the ventilation coefficient of the trajectory characteristic point is: Among them, Q cfd is the ventilation flow value obtained by CFD simulation; Q g is the ventilation flow value calculated by the one-dimensional isentropic calculation formula; K is the ventilation coefficient of the trajectory characteristic point.

4. The method for designing a ventilation system for a hypersonic vehicle according to any one of claims 1 to 3, characterized in that: The one-dimensional isentropic calculation formula is as follows: Among them, Q g represents ventilation flow; S represents ventilation area; γ represents specific heat ratio; P D is the downstream pressure; R is the gas constant; T U Represents the upstream temperature; Ma is a parameter.

5. The method for designing a ventilation system for a hypersonic vehicle according to claim 4, characterized in that: Among them, P U and P D are the upstream pressure and downstream pressure respectively; γ represents the specific heat ratio.

6. The method for designing a ventilation system for a hypersonic vehicle according to claim 5, characterized in that: The ventilation area S in the one-dimensional isentropic calculation formula is a given estimated value and is modified through iteration.

7. The method for designing a ventilation system for a hypersonic vehicle according to claim 6, characterized in that: During the rocket's ascent phase, the upstream pressure refers to the internal pressure value of the aircraft; the downstream pressure refers to the external pressure value of the aircraft.

8. The method for designing a ventilation system for a hypersonic vehicle according to claim 1, characterized in that: The process of one-dimensional isentropic calculation includes: According to the known external pressure value, the gas mass loss at the current moment is obtained by time difference calculation; According to the ideal gas state equation and the gas mass loss, the density and pressure of the gas in the cabin after the loss are solved; The solved density and pressure are substituted into the calculation formula of the ideal gas state equation at the next moment, and iterated repeatedly to obtain the internal pressure value and the internal and external pressure difference that change with time.

9. The method for designing a ventilation system for a hypersonic vehicle according to claim 8, characterized in that: The process of one-dimensional isentropic calculation also includes: Based on the internal pressure and external pressure values, calculate the change of Ma over time.

10. A hypersonic aircraft ventilation system, characterized in that: The system is obtained by the design method of the hypersonic vehicle ventilation system according to any one of claims 1 to 9, and the system comprises: an aircraft and a vent; The vent hole is arranged on the cabin of the aircraft, The ventilation area range and ventilation position of the ventilation hole are obtained according to the design method of the hypersonic vehicle ventilation system according to any one of claims 1-9.

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