Design method for equivalent thickness of aircraft air inlet simulation part

Abstract

The invention belongs to the technical field of structural thermal intensity, and particularly relates to a design method for equivalent thickness of an aircraft air inlet simulation part. According to the method, numerical simulation is carried out on the air inlet channel according to the given temperature load, and the highest temperature of the outer surface of the air inlet channel under the temperature load is obtained; the heat flow density required by the air inlet channel is calculated, the heat flow density is corrected and serves as a load to conduct numerical simulation on the air inlet channel, the highest temperature of the outer surface of the air inlet channel under the heat flow load is obtained, and the difference value between the highest temperature of the outer surface of the air inlet channel under the temperature load and the highest temperature of the outer surface of the air inlet channel under the heat flow density load meets the error requirement; the equivalent heat flux density is determined; establishing a finite element model for numerical simulation by taking the equivalent heat flux density as a load and the thickness of the new material simulation piece as a variable, so that a difference value between the maximum temperature of the outer surface of the new material simulation piece under the corrected thickness and the maximum temperature of the outer surface of the air inlet channel under the temperature load meets an error requirement; therefore, the thickness of the new material simulation piece meeting the requirement is determined.

Description

Technical Field

[0001] The present application belongs to the technical field of structural thermal strength, and in particular relates to a design method for the equivalent thickness of an aircraft air inlet simulation component. Background Art

[0002] As technology advances, aircraft will fly faster and their aerodynamic heating will become more severe. New heat-resistant materials and structures will also be widely used, and there will be more demand for ground-based simulated thermal strength tests. As demand increases, many tests have to face numerous uncertainties. For example: (1) Under high temperature conditions, the thermal conductivity and other properties of certain materials will change greatly, which will bring great disadvantages to test control and the estimation of test heating power; (2) Certain materials will peel off or precipitate powder particles at high temperatures, affecting the layout of temperature sensors and the accuracy of temperature measurement; (3) Test requirements are getting higher and higher, including temperature uniformity, temperature rise rate, etc., which brings many difficulties to test design.

[0003] In order to solve the influence of the above unfavorable factors on the thermal strength test, in addition to conducting preliminary tests on new materials, we should pay attention to the research on simulation tests, especially the design of equivalent simulation parts. Therefore, the design of equivalent thickness of aircraft inlet simulation parts has important engineering application value.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0005] The purpose of the present application is to provide a design method for the equivalent thickness of an aircraft air inlet simulation component to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] A design method for equivalent thickness of an aircraft air inlet simulation component, comprising:

[0008] Step 1: Get the upper limit of temperature error T min , calculation time step STEP, temperature load T load And flight time max ;

[0009] Step 2: Obtain the thickness h1 of the air inlet duct and the material thermophysical property parameters, construct an air inlet duct finite element model based on the thickness h1 of the air inlet duct and the material thermophysical property parameters, and convert the temperature load T load As a load, during the flight time max Performing numerical simulation FEM1 on the intake duct finite element model;

[0010] Step 3: Extract the numerical simulation FEM1 results, including the flight time max The outer surface temperature of the inlet duct is T1 out (i) and the intake duct inner surface temperature T1 in (i), i=1~STEP;

[0011] Step 4: Extract the intake duct outer surface temperature T1 out The maximum value T1 in (i) max ;

[0012] Step 5: According to the thickness h1 of the air inlet, the material thermophysical property parameters, and the outer surface temperature T1 of the air inlet out (i) and the intake duct inner surface temperature T1 in (i), calculate the inlet during the flight time time max The first heat flux density Q1(i) inside;

[0013] Step 6: Determine the second heat flux Q2(i) based on the first heat flux Q1(i), and use the second heat flux Q2(i) as the load at the flight time max Performing numerical simulation FEM2 on the intake duct finite element model;

[0014] Step 7: Extract numerical simulation FEM2 results, including the flight time max The outer surface temperature of the inlet duct is T2 out (i);

[0015] Step 8: Extract the intake duct outer surface temperature T2 out The maximum value T2 in (i) max ;

[0016] Step 9: Calculate the first relative error Err1 = T1 max -T2 max , determine whether the first relative error Err1 is greater than the temperature error upper limit T min ;

[0017] If yes, return to step 6 and re-determine the second heat flux Q2(i) based on the first heat flux Q1(i);

[0018] If not, proceed to step 10;

[0019] Step 10: Determine the thickness h2 of the simulated component according to the thickness h1 of the air inlet duct, obtain the material thermophysical property parameters of the simulated component, construct a finite element model of the simulated component according to the thickness h2 of the simulated component and the material thermophysical property parameters, and use the second heat flux density Q2(i) as the load. maxPerforming numerical simulation FEM3 on the finite element model of the simulation component;

[0020] Step 11: Extract numerical simulation FEM3 results, including the flight time max The outer surface temperature of the simulated part is T3 out (i);

[0021] Step 12: Extract the outer surface temperature T3 of the simulated part out The maximum value T3 in (i) max ;

[0022] Step 13: Calculate the second relative error Err2 = T1 max -T3 max , determine whether the second relative error Err2 is greater than the temperature error upper limit T min ;

[0023] If yes, return to step 10 and re-determine the thickness h2 of the simulation part according to the thickness h1 of the air intake duct;

[0024] If not, then end.

[0025] In at least one embodiment of the present application, the material thermophysical property parameters include heat transfer rate, specific heat capacity and density.

[0026] In at least one embodiment of the present application, in step 5, the first heat flux Q1(i) is:

[0027] Q1(i)=k1×[T1 out (i)-T1 in (i)]÷h1+c1×p1×h1×[T1 out (i)-T1 in (i)]

[0028] Where Q1(i) is the first heat flux, k1 is the heat transfer rate of the inlet duct, T1 out (i) is the inlet duct outer surface temperature, T1 in (i) is the inner surface temperature of the intake duct, h1 is the thickness of the intake duct, c1 is the specific heat capacity of the intake duct, p1 is the density of the intake duct, and i is the corresponding calculation time step, i=1~STEP.

[0029] In at least one embodiment of the present application, in step 6, the second heat flux Q2(i) is determined according to the first heat flux Q1(i) as:

[0030] Q2(i)=Q1(i)-Δ1(i)×Q1(i)

[0031] Wherein, Q2(i) is the second heat flux, Q1(i) is the first heat flux, and Δ1(i) is the heat flux increment.

[0032] In at least one embodiment of the present application, the heat flux increment Δ1(i) is:

[0033] Δ1(i)=2.0×Q1(i) / 100.0.

[0034] In at least one embodiment of the present application, in step 10, the thickness h2 of the simulation part is determined according to the thickness h1 of the air inlet duct as follows:

[0035] h2=h1-Δ2×h1

[0036] Wherein, h2 is the thickness of the simulated part, h1 is the thickness of the air intake duct, and Δ2 is the thickness increment.

[0037] In at least one embodiment of the present application, the thickness increment Δ2 is:

[0038] Δ2=2.0×h1 / 100.0.

[0039] The invention has at least the following beneficial technical effects:

[0040] The design method of the equivalent thickness of the aircraft air inlet duct simulation component of the present application realizes the calculation of the equivalent thickness of the aircraft air inlet duct simulation component based on the principle of equal heat absorption, and has important engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of a design method for equivalent thickness of an aircraft air inlet simulation component according to one embodiment of the present application;

[0042] Figure 2 It is a schematic diagram comparing the temperature curve of the outer surface of the air inlet under the temperature load and the heat flux density load of one embodiment of the present application;

[0043] Figure 3 It is a schematic diagram comparing the temperature curve of the outer surface of the air inlet duct and the temperature curve of the outer surface of the dummy component when the thickness of the dummy component and the air inlet duct are equal in one embodiment of the present application;

[0044] Figure 4 It is a schematic diagram comparing the outer surface temperature of the air inlet duct and the outer surface temperature curve of the simulated part when the simulated part is at an optimal thickness in one embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0046] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0047] The following is combined with Figures 1 to 4 This application is described in further detail.

[0048] The present application provides a design method for the equivalent thickness of an aircraft air inlet simulation component, such as Figure 1 As shown, the following steps are included:

[0049] Step 1: Get the upper limit of temperature error T min , calculation time step STEP, temperature load T load And flight time max ;

[0050] Step 2: Obtain the thickness h1 of the air inlet duct and the material thermophysical property parameters, construct the air inlet duct finite element model based on the thickness h1 of the air inlet duct and the material thermophysical property parameters, and set the temperature load T load As a load, during the flight time max Perform numerical simulation FEM1 on the intake duct finite element model;

[0051] Step 3: Extract the numerical simulation FEM1 results, including the flight time max The outer surface temperature of the inlet duct is T1 out (i) and the intake duct inner surface temperature T1 in (i), i=1~STEP;

[0052] Step 4: Extract the intake duct outer surface temperature T1 out The maximum value T1 in (i) max ;

[0053] Step 5: Based on the thickness h1 of the air inlet, the thermophysical property parameters of the material, and the outer surface temperature T1 of the air inlet out (i) and the intake duct inner surface temperature T1 in (i) Calculate the inlet time during flight max The first heat flux density Q1(i) inside;

[0054] Step 6: Determine the second heat flux Q2(i) based on the first heat flux Q1(i), and use the second heat flux Q2(i) as the load at the flight time max Numerical simulation of the intake duct finite element model is performed in FEM2;

[0055] Step 7: Extract numerical simulation FEM2 results, including the flight time max The outer surface temperature of the inlet duct is T2 out (i);

[0056] Step 8: Extract the intake duct outer surface temperature T2 out The maximum value T2 in (i) max ;

[0057] Step 9: Calculate the first relative error Err1 = T1 max -T2 max , determine whether the first relative error Err1 is greater than the temperature error upper limit T min ;

[0058] If yes, return to step 6 and re-determine the second heat flux Q2(i) based on the first heat flux Q1(i);

[0059] If not, proceed to step 10;

[0060] Step 10: Determine the thickness h2 of the simulated component according to the thickness h1 of the air inlet duct, obtain the material thermophysical property parameters of the simulated component, construct a finite element model of the simulated component according to the thickness h2 of the simulated component and the material thermophysical property parameters, and use the second heat flux density Q2(i) as the load. max Perform numerical simulation of the finite element model of the simulation part in FEM3;

[0061] Step 11: Extract numerical simulation FEM3 results, including the flight time max The outer surface temperature of the simulated part is T3 out (i);

[0062] Step 12: Extract the outer surface temperature T3 of the simulated part out The maximum value T3 in (i) max ;

[0063] Step 13: Calculate the second relative error Err2 = T1 max -T3 max , determine whether the second relative error Err2 is greater than the temperature error upper limit T min ;

[0064] If yes, return to step 10 and re-determine the thickness h2 of the simulation part according to the thickness h1 of the air intake duct;

[0065] If not, then end.

[0066] In a preferred embodiment of the present application, in step 2, a finite element model of the intake duct is constructed based on the thickness h1 of the intake duct and the material thermophysical property parameters, and the material thermophysical property parameters used include three physical quantities: conductivity k1, specific heat capacity c1 and density p1 of the intake duct.

[0067] In a preferred embodiment of the present application, in step 5, according to the thickness h1 of the air inlet duct, the thermophysical property parameters of the material, the outer surface temperature T1 of the air inlet duct out (i) and the intake duct inner surface temperature T1 in (i) Calculate the inlet time during flight max The first heat flux density Q1(i) in the , wherein the first heat flux density Q1(i) is:

[0068] Q1(i)=k1×[T1 out (i)-T1 in (i)]÷h1+c1×p1×h1×[T1 out (i)-T1 in (i)]

[0069] Where Q1(i) is the first heat flux, k1 is the heat transfer rate of the inlet duct, T1 out (i) is the inlet duct outer surface temperature, T1 in (i) is the inner surface temperature of the intake duct, h1 is the thickness of the intake duct, c1 is the specific heat capacity of the intake duct, p1 is the density of the intake duct, and i is the corresponding calculation time step, i=1~STEP.

[0070] The unit of the first heat flux Q1(i) is J / m 2 , the unit of heat transfer rate k1 is W / (m·K), the temperature of the outer surface of the inlet duct is T1 out (i) Inlet duct inner surface temperature T1 inThe unit of (i) is °C, the unit of the thickness of the intake duct h1 is m, the unit of the specific heat capacity of the intake duct c1 is J / (Kg·K), and the unit of the density of the intake duct p1 is kg / m 3 .

[0071] In a preferred embodiment of the present application, in step 6, the second heat flux Q2(i) is determined according to the first heat flux Q1(i):

[0072] Q2(i)=Q1(i)-Δ1(i)×Q1(i)

[0073] Wherein, Q2(i) is the second heat flux, Q1(i) is the first heat flux, and Δ1(i) is the heat flux increment.

[0074] The units of the second heat flux Q2(i) and the heat flux increment Δ1(i) are both J / m 2 .

[0075] The heat flux increment Δ1(i) is:

[0076] Δ1(i)=2.0×Q1(i) / 100.0.

[0077] According to the heat flux increment, it can be seen that in each cycle iteration, the second heat flux Q2(i) is reduced by %2 of the first heat flux based on the heat flux of the previous cycle.

[0078] In one embodiment of the present application, a set of numerical simulation results FEM1 and numerical simulation FEM2 obtained according to step 3 and step 7 are compared. Figure 2 Through the iterative cycle from step 6 to step 9, the second heat flux density Q2(i) that meets the requirements can be obtained, which is used as the input load for the numerical simulation of the intake duct simulation component.

[0079] In a preferred embodiment of the present application, in step 10, the thickness h2 of the simulation part is determined according to the thickness h1 of the air inlet duct:

[0080] h2=h1-Δ2×h1

[0081] Wherein, h2 is the thickness of the simulated part, h1 is the thickness of the air intake duct, and Δ2 is the thickness increment.

[0082] The units of the thickness h1 and the thickness increment Δ2 of the air intake duct are both m.

[0083] The thickness increment Δ2 is:

[0084] Δ2=2.0×h1 / 100.0.

[0085] According to the thickness increment, it can be known that in each cycle iteration, the thickness h2 of the simulation part is reduced by %2 of the thickness of the air intake duct based on the thickness of the previous cycle.

[0086] In this embodiment, a new material is selected to design a simulation part, and after obtaining the thickness h2 of the simulation part and the material thermophysical property parameters, a finite element model of the simulation part is constructed based on the thickness h2 of the simulation part and the material thermophysical property parameters. The material thermophysical property parameters used include three physical quantities: conductivity k2, specific heat capacity c2 and density p2 of the simulation part.

[0087] In one embodiment of the present application, the comparison of the results of the two sets of numerical simulation FEM1 and numerical simulation FEM3 obtained according to step 3 and step 11 is as follows: Figure 3 , 4 Through the iterative cycle from step 10 to step 13, the thickness h2 of the simulation part that meets the requirements can be obtained, thereby realizing the equivalent thickness design of the aircraft air inlet simulation part of the new material.

[0088] The design method of the equivalent thickness of the aircraft inlet duct simulation part of the present application is as follows: first, the inlet duct is numerically simulated with a given temperature load during the entire flight time period to obtain the maximum temperature of the outer surface of the inlet duct under the temperature load; then the heat flux density required for the inlet duct during the entire flight time period is calculated, the aforementioned heat flux density is corrected and used as a load to perform numerical simulation on the inlet duct to obtain the maximum temperature of the outer surface of the inlet duct during the entire flight time period under the heat flux load, so that the difference between the maximum temperature of the outer surface of the inlet duct under the temperature load and the maximum temperature of the outer surface of the inlet duct under the heat flux load meets the error requirement, thereby determining the equivalent heat flux density; finally, a finite element model is established with the equivalent heat flux density as the load and the thickness of the new material simulation part as the variable (the initial thickness is the inlet duct thickness) to perform numerical simulation, so that the difference between the maximum temperature of the outer surface of the simulation part of the new material under the corrected thickness and the maximum temperature of the outer surface of the inlet duct under the temperature load meets the error requirement, thereby determining the thickness of the new material simulation part that meets the requirements.

[0089] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A design method for equivalent thickness of an aircraft air inlet simulation component, characterized in that: include: Step 1: Get the upper limit of temperature error T min , calculation time step STEP, temperature load T load And flight time max ; Step 2: Obtain the thickness h1 of the air inlet duct and the material thermophysical property parameters, construct an air inlet duct finite element model based on the thickness h1 of the air inlet duct and the material thermophysical property parameters, and convert the temperature load T load As a load, during the flight time max Performing numerical simulation FEM1 on the intake duct finite element model; Step 3: Extract the numerical simulation FEM1 results, including the flight time max The outer surface temperature of the inlet duct is T1 out (i) and the intake duct inner surface temperature T1 in (i), i=1~STEP; Step 4: Extract the intake duct outer surface temperature T1 out The maximum value T1 in (i) max ; Step 5: According to the thickness h1 of the air inlet, the material thermophysical property parameters, and the outer surface temperature T1 of the air inlet out (i) and the intake duct inner surface temperature T1 in (i), calculate the inlet during the flight time time max The first heat flux density Q1(i) inside; Step 6: Determine the second heat flux Q2(i) based on the first heat flux Q1(i), and use the second heat flux Q2(i) as the load at the flight time max Performing numerical simulation FEM2 on the air intake finite element model; Step 7: Extract numerical simulation FEM2 results, including the flight time max The outer surface temperature of the inlet duct is T2 out (i); Step 8: Extract the intake duct outer surface temperature T2 out The maximum value T2 in (i) max ; Step 9: Calculate the first relative error Err1 = T1 max -T2 max , determine whether the first relative error Err1 is greater than the temperature error upper limit T min ; If yes, return to step 6 and re-determine the second heat flux Q2(i) based on the first heat flux Q1(i); If not, proceed to step 10; Step 10: Determine the thickness h2 of the simulated component according to the thickness h1 of the air inlet duct, obtain the material thermophysical property parameters of the simulated component, construct a finite element model of the simulated component according to the thickness h2 of the simulated component and the material thermophysical property parameters, and use the second heat flux density Q2(i) as the load. max Performing numerical simulation FEM3 on the finite element model of the simulation component; Step 11: Extract numerical simulation FEM3 results, including the flight time max The outer surface temperature of the simulated part is T3 out (i); Step 12: Extract the outer surface temperature T3 of the simulated part out The maximum value T3 in (i) max ; Step 13: Calculate the second relative error Err2 = T1 max -T3 max , determine whether the second relative error Err2 is greater than the temperature error upper limit T min ; If yes, return to step 10 and re-determine the thickness h2 of the simulation part according to the thickness h1 of the air intake duct; If not, then end.

2. The design method for equivalent thickness of an aircraft air inlet simulation component according to claim 1, characterized in that: The material thermophysical property parameters include heat transfer rate, specific heat capacity and density.

3. The design method of equivalent thickness of an aircraft air inlet simulation component according to claim 2, characterized in that: In step 5, the first heat flux Q1(i) is: Q1(i)=k1×[T1 out (i)-T1 in (i)]÷h1+c1×p1×h1×[T1 out (i)-T1 in (in)] Where Q1(i) is the first heat flux, k1 is the heat transfer rate of the inlet duct, T1 out (i) is the inlet duct outer surface temperature, T1 in (i) is the inner surface temperature of the intake duct, h1 is the thickness of the intake duct, c1 is the specific heat capacity of the intake duct, p1 is the density of the intake duct, and i is the corresponding calculation time step, i=1~STEP.

4. The design method for equivalent thickness of an aircraft air inlet simulation component according to claim 3, characterized in that: In step 6, the second heat flux Q2(i) is determined according to the first heat flux Q1(i): Q2(i)=Q1(i)-Δ1(i)×Q1(i) Wherein, Q2(i) is the second heat flux, Q1(i) is the first heat flux, and Δ1(i) is the heat flux increment.

5. The design method for equivalent thickness of an aircraft air inlet simulation component according to claim 4, characterized in that: The heat flux increment Δ1(i) is: Δ1(i)=2.0×Q1(i) / 100.

0.

6. The design method for equivalent thickness of an aircraft air inlet simulation component according to claim 5, characterized in that: In step 10, the thickness h2 of the simulation part is determined according to the thickness h1 of the air inlet duct: h2=h1-Δ2×h1 Wherein, h2 is the thickness of the simulated part, h1 is the thickness of the air intake duct, and Δ2 is the thickness increment.

7. The design method for equivalent thickness of an aircraft air inlet simulation component according to claim 6, characterized in that: The thickness increment Δ2 is: Δ2=2.0×h1 / 100.0.

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