Multi-branch flow distribution method for cooling system in aircraft thermal environment

Abstract

The present invention relates to the field of aircraft, and specifically to a multi-branch flow distribution method for a cooling system in a thermal environment of an aircraft. Data tables A and B are prepared by testing each branch and resistance component in advance, and the data tables A and B can be used repeatedly in subsequent iterations of the aircraft. A flow distribution algorithm is established according to the data tables A and B and distribution coefficients. When calculating, directly calling the table data can greatly reduce the amount of calculation for flow distribution. Screening conditions are set to verify the result of the distribution algorithm, thereby improving the pass rate of a theoretical group of resistance components. A flow control valve is used to simulate resistance changes at different temperatures, and a simulated high-temperature test is performed on the theoretical group of resistance components to obtain a practical group of resistance components that can be directly installed on the aircraft, thereby avoiding the difficulty of high-temperature tests, the huge amount of calculations and the high cost, and ensuring the rationality and reliability of multi-branch flow distribution.

Description

Technical Field

[0001] The present invention relates to the field of aircraft, and in particular to a multi-branch flow distribution method for a cooling system in an aircraft thermal environment. Background Art

[0002] Aircraft internal devices or external components often have different thermal environments, such as internal power equipment, high-power equipment, external control components, etc. For components with different temperatures in different places, different degrees of passive / active thermal protection are usually adopted to ensure that they will not fail due to over-temperature. Aircraft active cooling generally adopts different methods such as air cooling or liquid cooling. The appropriate cooling technology is selected according to the specific use environment. The cooling medium absorbs and removes the heat from the severely heated parts through the channels or pipes located in the cooling structure.

[0003] In the aircraft cooling system, when the coolant passes through a branch channel or pipeline, the high temperature will cause the coolant to undergo drastic changes in physical and chemical properties, the pressure in the local channel will rise, the resistance will increase, the cooling effect will decrease, and then a negative feedback will be formed. The temperature will continue to rise, the resistance will increase, and the cooling effect will continue to decrease until it is damaged by overheating. In order to avoid this phenomenon, the flow of each branch cooling pipeline must be allocated and designed at the beginning of the cooling system design.

[0004] The complex thermal environment of aircraft often leads to large temperature differences among components, even hundreds or thousands of degrees. In addition to high temperatures, the temperature of each functional component varies greatly, which not only affects the branch resistance, but also affects the flow distribution of other branches, and the relative temperature will also switch. At this time, the branch resistance will fluctuate over a very large range, and the following phenomena may occur: (1) The resistance of each branch is very large at the same time; (2) The resistance of branch A is large, and the resistance of branch B is small...; (3) The resistance of branch B is large, and the resistance of branch A is small... (the opposite of 2); (4) In the case of multiple branches, the temperature distribution combination of each branch is more complex; the traditional method of solving the above problems will have the following difficulties:

[0005] 1) The resistance values ​​of each branch vary widely, and their relative sizes will also vary, so it is impossible to directly determine a resistance value benchmark to match the appropriate resistance components;

[0006] For example, taking the larger resistance value PB of branch A and branch B as the benchmark, branch A is matched with the resistance component PB-PA to make the resistance of each branch consistent. However, due to the large resistance variation range, when the resistance of branch A takes a small value Pa, the resistance of branch B takes a large value PB. After configuring the resistance component, the resistance difference between the two branches is PA-Pa. The larger the branch resistance value variation range, the greater the difference. This difference will cause differences in the cooling fluid flow distribution of each branch.

[0007] For example, taking the sum of the resistances of branch A and branch B as a benchmark, branch A is matched with resistance component PB, and branch B is matched with resistance component PA, so that the resistances of each branch are consistent. When the resistance of branch A takes a small value Pa, and branch B takes a large value PB, the resistance difference between the two branches after configuring the resistance components is (PB+PA)-(PB+Pa)=PA-Pa. Similarly, the greater the range of branch resistance values, the greater the difference. This difference will cause differences in the cooling fluid flow distribution of each branch.

[0008] 2) The actual temperature variation range of each branch is large. Simply measuring the branch resistance at the highest temperature will cause distortion of the test results of multiple branch combination tests. Simulating a wide range of high temperature test environments will greatly increase the test workload. When there are many components and branches to be cooled, the variable of the test temperature of each branch combination is also required, which will increase the test workload even more. It is difficult to implement this test plan in high energy consumption and high temperature tests.

[0009] 3) The existing flow distribution and design methods are always conservative and use large resistance components, whose resistance value is much greater than the actual resistance of the functional components, in order to achieve the purpose of relatively small deviation of the total resistance value of each branch. However, this solution will greatly increase the upstream pressure supply power and pipeline pressure, that is, increase the weight and cost of equipment and pipelines, and also bring more risks to the entire system.

[0010] 4) When there are fewer branches, it is feasible to directly add a resistance component with a specific resistance value to a branch for flow distribution. However, when there are many branches and the temperature changes of each branch lead to large changes in resistance, it is very difficult to find a set of suitable resistance components that can meet any temperature combination. It is necessary to frequently change the temperature environment of each functional component, match the resistance components for iterative verification, and frequently open and close the high temperature test equipment, which is almost impossible to achieve in actual tests. Summary of the invention

[0011] The technical problem that the present application aims to solve is to provide a multi-branch flow distribution method for a cooling system in an aircraft thermal environment. As the number of branches in the cooling system increases, the amount of calculation required for flow distribution increases exponentially. A flow distribution algorithm is established based on data tables A and B and distribution coefficients. Directly calling table data during calculation can significantly reduce the amount of calculation required for flow distribution. A flow control valve is used to simulate resistance changes at different temperatures, thereby avoiding the difficulty and cost of high temperature testing.

[0012] The specific technical solution of the present application is: a multi-branch flow distribution method for a cooling system in an aircraft thermal environment, wherein each branch in the cooling system has only one stable flow state when the upstream and downstream pressures and resistances are constant, and each branch of the cooling system is connected with a functional component and a resistance component, and is characterized in that the multi-branch flow distribution method for the cooling system comprises the following steps:

[0013] S1. Simplify each branch of the cooling system according to the flow direction of the cooling medium and make a parallel branch model in the computer;

[0014] S2a, respectively measure the resistance of the functional components of each branch in the parallel branch model at different temperatures and a certain flow rate, calculate the flow coefficient C corresponding to the temperature and flow rate, calculate the resistance value of each branch at different temperatures and different flow rates according to the flow-resistance calculation formula, and prepare a data table A; the flow-resistance calculation formula is as follows:

[0015]

[0016] Where: q m :flow;

[0017] C: flow coefficient;

[0018] A: cross-sectional area;

[0019] ΔP: resistance, expressed as pressure difference;

[0020] ρ: cooling medium density;

[0021] S2b, conduct a flow-resistance test on the resistance component, obtain the flow-resistance relationship of the resistance component, and prepare a data table B;

[0022] S2c, assigning a distribution coefficient to the flow of each branch based on the ratio of the highest temperature that may occur in the actual operation of the branch to the highest allowable temperature of the components in the branch and whether there are key components in the branch;

[0023] S3, conduct a flow-resistance test on each branch, establish a flow distribution algorithm according to data table A, data table B and distribution coefficient, in which the sum of the flow of each branch is equal to the total flow and the resistance of each branch is equal, and match the resistance component for each branch through the flow distribution algorithm;

[0024] Set the screening conditions for the resistance components in a single branch. If the screening is passed, it means that the resistance components set in this branch are qualified, and the specifications of the resistance components of this branch are recorded at this time; if the screening is not passed, replace the resistance components of this branch and repeat this step; the screening conditions are as follows:

[0025] (Max(flow rate / distribution coefficient)-Min(flow rate / distribution coefficient)) / (total flow rate / number of branches)=n <N;

[0026] Where: n is the flow deviation; N is the allowable deviation, which is within 10%;

[0027] After the resistance components in each branch have passed the screening, the resistance components of qualified specifications in each branch form a theoretical group of resistance components;

[0028] S4. Use multiple flow control valves to replace the functional components connected to each branch to build a flow-resistance test platform to conduct a high-temperature simulation test on the resistance component theory group. The flow control valve and the resistance component in a single branch are connected in series, and the flow control valve is used to simulate the resistance of the branch at different temperatures; supply flow to the flow-resistance test platform connected to the resistance component theory group, and make the initial flow distribution of each branch meet the total flow / number of branches*distribution coefficient. Combined with the typical temperature distribution conditions of the aircraft in the daily use environment, the resistance value of the flow control valve corresponding to the temperature distribution condition is set in the resistance change design range of 0-150% of each branch to form a test condition matrix;

[0029] S5. Perform a flow-resistance test on the test condition matrix, record the flow distribution data of each branch, and calculate the flow deviation n of each branch through the screening conditions in S6. If the screening conditions are met, the flow distribution of the branch is reasonable; if the screening conditions are not met, repeat S4 and S5 until the flow distribution of all branches meets the screening conditions, thereby obtaining a practice group of resistance components for installing an aircraft.

[0030] Furthermore, the flow rate of each branch is assigned distribution coefficients based on the ratio of the maximum temperature that may occur in the actual operation of the branch to the maximum allowable temperature of the components in the branch and whether there are key components in the branch: if the temperature exceeds the maximum allowable temperature by 20%, the branch with key components is assigned a distribution coefficient of 1.2-1.5, and the branch without key components is assigned a distribution coefficient of 1-1.1; if the temperature exceeds the maximum allowable temperature by 0-20%, the branch with key components is assigned a distribution coefficient of 1.1-1.3, and the branch without key components is assigned a distribution coefficient of 1; if the temperature does not exceed the maximum allowable temperature, the branch with key components is assigned a distribution coefficient of 1, and the branch without key components is assigned a distribution coefficient of 0.7-0.9.

[0031] Furthermore, the flow distribution algorithm is as follows:

[0032] Branch i and branch j are preliminarily selected for connection based on engineering experience, and the initial flow q of branch i and branch j is set respectively. i and q j , the formula for setting the initial flow is: initial flow = total flow / number of branches * allocation coefficient, call data table A and table B to calculate the total resistance of branch i and branch j according to the flow-resistance calculation formula;

[0033] Calculate the total resistance of branch i minus the total resistance of branch j. If the total resistance of branch i is greater than the total resistance of branch j, update the flow of branch i to the initial flow q. i *(1-s), the flow of branch j is updated to the initial flow q j*(1+s), s is the calculation step length, which is 0.01-0.1; if the total resistance of branch i is less than the total resistance of branch j, the flow of branch i is the initial flow q i *(1+s), the flow of branch j is updated to the initial flow q j *(1-s); Repeat the calculation until the total resistance of branch i - the total resistance of branch j = 0±u, where u is the convergence error value. Record the flow data of each branch at this time and the resistance components in the branch that meet the algorithm conditions.

[0034] Further preferably, for branches with similar temperature, flow and resistance characteristics, the calculation of such branches is omitted, and the theoretical required flow of the omitted branches is subtracted from the total flow.

[0035] Further preferably, a flow-resistance test platform is built in the order of the flow deviation n of a single branch to verify the theoretical group of resistance components.

[0036] Preferably, the flow control valve is a flow control valve with multi-stage adjustable resistance value or a flow control valve with continuously adjustable resistance value.

[0037] Preferably, the resistance value of the flow control valve is randomly set within 0-150% of the resistance variation design range of each branch.

[0038] Preferably, the minimum value, the middle value and the maximum value are selected from the resistance variation design range of 0-150% of each branch, and the flow control valve is adjusted so that the total resistance of each branch randomly meets the minimum value, the middle value and the maximum value setting of the corresponding branch.

[0039] Further preferably, the branch resistance value with a distribution coefficient above 1.1 is preferentially set to the maximum value, and the total resistance of the remaining branches randomly satisfies the corresponding branch minimum value, intermediate value and maximum value settings.

[0040] Preferably, there are multiple groups of resistance component practice groups that meet the screening condition formula according to the test results, and one of them is selected in turn according to the cooling effect, pipeline pressure and processing difficulty to install the aircraft.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] As the number of cooling system branches in an aircraft increases, the amount of calculation required for flow distribution increases exponentially. This application prepares data tables A and B by testing each branch and resistance component in advance. Data tables A and B can be used repeatedly in subsequent aircraft iterations. A flow distribution algorithm is established based on data tables A and B and distribution coefficients. Directly calling table data during calculation can greatly reduce the amount of calculation required for flow distribution. Screening conditions are set to verify the results of the distribution algorithm and improve the pass rate of the theoretical group of resistance components. A flow control valve is used to simulate the resistance changes at different temperatures, and a simulated high-temperature test is performed on the theoretical group of resistance components to obtain a practical group of resistance components that can be directly installed on the aircraft. This avoids the difficulty and huge amount of calculation required for high-temperature tests and the high cost, while ensuring the rationality and reliability of multi-branch flow distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of a flow-resistance test platform according to an embodiment of the present application;

[0044] In the figure: 1. Resistance component; 2. Flow control valve; 3. Differential pressure sensor; 4. Flow sensor; 5. Flow source; 6. Recovery end. DETAILED DESCRIPTION

[0045] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0046] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0047] Example

[0048] This embodiment provides a multi-branch flow distribution method for a cooling system in a thermal environment of an aircraft, wherein each branch in the cooling system has only one stable flow state when the upstream and downstream pressures and resistances are constant, and each branch of the cooling system is connected with a functional component and a resistance component, and is characterized in that the multi-branch flow distribution method for the cooling system comprises the following steps:

[0049] S1. Sort out the branches of the cooling system, simplify the branches of the cooling system according to the flow direction of the cooling medium, and make a parallel branch model in the computer.

[0050] S2a, respectively measure the resistance of the functional components of each branch in the parallel branch model at different temperatures and a certain flow rate, calculate the flow coefficient C corresponding to the temperature and flow rate, and after the flow coefficient C is determined, the flow rate and resistance in the branch can be calculated from each other. According to the flow-resistance calculation formula, calculate the resistance value of each branch at different temperatures and different flow rates, and make a data table A; the flow-resistance calculation formula is as follows:

[0051]

[0052] Where: q m :flow;

[0053] C: flow coefficient;

[0054] A: cross-sectional area;

[0055] ΔP: resistance, expressed as pressure difference;

[0056] ρ: cooling medium density.

[0057] S2b. Perform a flow-resistance test on the resistance component to obtain the flow-resistance relationship of the resistance component and prepare data table B. Because the resistance component is a standard part, data table B can be used repeatedly in subsequent product updates and iterations, greatly reducing the amount of calculation.

[0058] S2c. The flow rate of each branch is assigned a distribution coefficient based on the ratio of the highest temperature that may occur in the actual operation of the branch to the designed maximum allowable temperature of the components in the branch and whether there are key components in the branch: if the temperature exceeds the maximum allowable temperature by 20%, the branch with key components is assigned a distribution coefficient of 1.2-1.5, and the branch without key components is assigned a distribution coefficient of 1-1.1; if the temperature exceeds the maximum allowable temperature by 0-20%, the branch with key components is assigned a distribution coefficient of 1.1-1.3, and the branch without key components is assigned a distribution coefficient of 1; if the temperature does not exceed the maximum allowable temperature, the branch with key components is assigned a distribution coefficient of 1, and the branch without key components is assigned a distribution coefficient of 0.7-0.9.

[0059] S3, conduct a flow-resistance test on each branch, establish a flow distribution algorithm according to data table A, data table B and distribution coefficient, in which the sum of the flow of each branch is equal to the total flow and the resistance of each branch is equal, and match the resistance component for each branch through the flow distribution algorithm;

[0060] Set the screening conditions for the resistance components in a single branch. If the screening is passed, it means that the resistance components set in this branch are qualified, and the specifications of the resistance components of this branch are recorded at this time; if the screening is not passed, replace the resistance components of this branch and repeat this step; the screening conditions are as follows:

[0061] (Max(flow rate / distribution coefficient)-Min(flow rate / distribution coefficient)) / (total flow rate / number of branches)=n <N;

[0062] Where: n is the flow deviation; N is the allowable deviation, which is within 10%;

[0063] After the resistance components in each branch have passed the screening, the resistance components of qualified specifications in each branch form a theoretical group of resistance components.

[0064] The flow distribution algorithm described in this embodiment is as follows:

[0065] Branch i and branch j are preliminarily selected for connection based on engineering experience, and the initial flow q of branch i and branch j is set respectively. i and q j , the formula for setting the initial flow is: initial flow = total flow / number of branches * allocation coefficient, call data table A and table B to calculate the total resistance of branch i and branch j according to the flow-resistance calculation formula;

[0066] Calculate the total resistance of branch i minus the total resistance of branch j. If the total resistance of branch i is greater than the total resistance of branch j, update the flow of branch i to the initial flow q. i *(1-s), the flow of branch j is updated to the initial flow q j *(1+s), s is the calculation step length, which is 0.01-0.1; if the total resistance of branch i is less than the total resistance of branch j, the flow of branch i is the initial flow q i *(1+s), the flow of branch j is updated to the initial flow q j *(1-s); Repeat the calculation until the total resistance of branch i - the total resistance of branch j = 0±u, where u is the convergence error value. Record the flow data of each branch at this time and the resistance components in the branch that meet the algorithm conditions.

[0067] S4, such as Figure 1 As shown, according to the order of the flow deviation n of a single branch in the theoretical group of resistance components, a flow-resistance test platform is built by using multiple flow control valves to replace the functional components connected to each branch to conduct a high-temperature simulation test on the theoretical group of resistance components. The flow control valve is a flow control valve with a multi-stage resistance value adjustment or a continuous resistance value adjustment. The flow control valve in a single branch is connected in series with the resistance component, and the flow control valve is used to simulate the resistance of the branch at different temperatures; the flow is supplied to the flow-resistance test platform connected to the theoretical group of resistance components, and the initial flow distribution of each branch satisfies the total flow / number of branches*distribution coefficient. Combined with the typical temperature distribution conditions of the aircraft in the daily use environment, the resistance value of the flow control valve corresponding to the temperature distribution condition is set in the 0-150% of the resistance change design range of each branch to form a test condition matrix.

[0068] Preferably, when the aircraft temperature distribution in the entry use environment cannot be determined, the resistance value of the flow control valve is randomly set within 0-150% of the resistance variation design range of each branch.

[0069] Preferably, to simplify the amount of calculation, the minimum, middle and maximum values ​​are selected from the resistance variation design range of 0-150% of each branch, and the flow control valve is adjusted so that the total resistance of each branch randomly meets the minimum, middle and maximum settings of the corresponding branch.

[0070] Further preferably, the branch resistance value with a distribution coefficient above 1.1 is preferentially set to the maximum value, and the total resistance of the remaining branches randomly satisfies the corresponding branch minimum value, intermediate value and maximum value settings.

[0071] The flow control valve is used to simulate the different resistance of branches or components at different temperatures, which saves the construction of complex and expensive high-energy consumption high-temperature environment system equipment or places. During the test, the flow control valve resistance value needs to be randomly set within the range of branch resistance variation. A differential pressure sensor or flow sensor is set at both ends of the flow control component and the flow control valve to measure the pressure difference or flow.

[0072] S5. Perform a flow-resistance test on the test condition matrix, record the flow distribution data of each branch, and calculate the flow deviation n of each branch through the screening conditions in S6. If the screening conditions are met, the flow distribution of the branch is reasonable; if the screening conditions are not met, repeat S4 and S5 until the flow distribution of all branches meets the screening conditions, thereby obtaining a practice group of resistance components for installing an aircraft.

[0073] Further preferably, for branches with similar temperature, flow and resistance characteristics, the calculation of such branches is omitted, and the theoretical required flow of the omitted branches is subtracted from the total flow (total flow / number of branches*distribution coefficient). This will greatly reduce the amount of calculation, and the omitted branches can be matched with the flow control components of similar branches.

[0074] Preferably, there are multiple groups of resistance component practice groups that meet the screening condition formula according to the test results, and one of them is selected in turn according to the cooling effect, pipeline pressure and processing difficulty to install the aircraft.

[0075] This application only needs to measure the high temperature-flow-resistance relationship of each functional component separately, and there is no need to carry out large-scale high-energy consumption high-temperature tests at the same time, which improves the feasibility of the test. By establishing a flow distribution algorithm and resistance component screening conditions for a theoretical group of resistance components based on the flow distribution coefficient, a large amount of manual calculation work can be avoided, and a large number of resistance components can be used to assemble and test in sequence and iterate, saving test time and cost. By setting a flow control valve to replace the functional components with temperature changes, the test to verify the theoretical group of resistance components does not need to conduct multi-branch high-temperature tests, which greatly reduces the cost and risk of high-temperature tests. At the same time, more branch temperature combination verifications can be achieved, making the resistance design results more reliable.

[0076] This application does not need to uniformly use conservative large resistance flow control components to balance the flow of each branch, reduce the cooling system supply pressure and pipeline pressure, and reduce the weight and cost of equipment and pipelines. At the same time, the problem of large changes in resistance of functional components at different temperatures is fully considered, and the flow of each branch under different thermal environments can still meet the design requirements.

[0077] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0078] One or more embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A multi-branch flow distribution method for a cooling system in an aircraft thermal environment, wherein each branch in the cooling system has only one stable flow state when the upstream and downstream pressures and resistances are constant, and each branch of the cooling system is connected with a functional component and a resistance component, characterized in that: The multi-branch flow distribution method of the cooling system comprises the following steps: S1. Simplify each branch of the cooling system according to the flow direction of the cooling medium and make a parallel branch model in the computer; S2a, respectively measure the resistance of the functional components of each branch in the parallel branch model at different temperatures and a certain flow rate, calculate the flow coefficient C corresponding to the temperature and flow rate, calculate the resistance value of each branch at different temperatures and different flow rates according to the flow-resistance calculation formula, and prepare a data table A; the flow-resistance calculation formula is as follows: Where: q m :flow; C: flow coefficient; A: cross-sectional area; ΔP: resistance, expressed as pressure difference; ρ: cooling medium density; S2b, conduct a flow-resistance test on the resistance component, obtain the flow-resistance relationship of the resistance component, and prepare a data table B; S2c, assigning a distribution coefficient to the flow of each branch based on the ratio of the highest temperature that may occur in the actual operation of the branch to the highest allowable temperature of the components in the branch and whether there are key components in the branch; S3, conduct a flow-resistance test on each branch, establish a flow distribution algorithm according to data table A, data table B and distribution coefficient, in which the sum of the flow of each branch is equal to the total flow and the resistance of each branch is equal, and match the resistance component for each branch through the flow distribution algorithm; Set the screening conditions for the resistance components in a single branch. If the screening is passed, it means that the resistance components set in this branch are qualified, and the specifications of the resistance components of this branch are recorded at this time; if the screening is not passed, replace the resistance components of this branch and repeat this step; the screening conditions are as follows: (Max(flow rate / distribution coefficient)-Min(flow rate / distribution coefficient)) / (total flow rate / number of branches)=n <N; Where: n is the flow deviation; N is the allowable deviation, which is within 10%; After the resistance components in each branch have passed the screening, the resistance components of qualified specifications in each branch form a theoretical group of resistance components; S4. Use multiple flow control valves to replace the functional components connected to each branch to build a flow-resistance test platform to conduct a high-temperature simulation test on the resistance component theory group. The flow control valve and the resistance component in a single branch are connected in series, and the flow control valve is used to simulate the resistance of the branch at different temperatures; supply flow to the flow-resistance test platform connected to the resistance component theory group, and make the initial flow distribution of each branch meet the total flow / number of branches*distribution coefficient. Combined with the typical temperature distribution conditions of the aircraft in the daily use environment, the resistance value of the flow control valve corresponding to the temperature distribution condition is set in the resistance change design range of 0-150% of each branch to form a test condition matrix; S5, conduct a flow-resistance test on the test condition matrix, record the flow distribution data of each branch, and calculate the flow deviation n of each branch through the screening conditions in S6. If the screening conditions are met, the flow distribution of the branch is reasonable; If the screening condition is not met, S4 and S5 are repeated until the flow distribution of all branches meets the screening condition, thereby obtaining a practical group of resistance components for installing an aircraft.

2. The multi-branch flow distribution method for a cooling system in an aircraft thermal environment according to claim 1, characterized in that: The flow rate of each branch is assigned a distribution coefficient based on the ratio of the highest temperature that may occur in the actual operation of the branch to the highest allowable temperature of the components in the branch and whether there are key components in the branch: if the temperature exceeds the highest allowable temperature by 20%, the branch with key components is assigned a distribution coefficient of 1.2-1.5, and the branch without key components is assigned a distribution coefficient of 1-1.1; if the temperature exceeds the highest allowable temperature by 0-20%, the branch with key components is assigned a distribution coefficient of 1.1-1.3, and the branch without key components is assigned a distribution coefficient of 1; If the maximum permissible temperature is not exceeded, the branch with critical components is assigned a distribution coefficient of 1, and the mass without critical components is assigned a distribution coefficient of 0.7-0.

9.

3. The multi-branch flow distribution method for a cooling system in an aircraft thermal environment according to claim 1, characterized in that: The traffic distribution algorithm is as follows: Branch i and branch j are preliminarily selected for connection based on engineering experience, and the initial flow q of branch i and branch j is set respectively. i and q j , the formula for setting the initial flow is: initial flow = total flow / number of branches * allocation coefficient, call data table A and table B to calculate the total resistance of branch i and branch j according to the flow-resistance calculation formula; Calculate the total resistance of branch i minus the total resistance of branch j. If the total resistance of branch i is greater than the total resistance of branch j, update the flow of branch i to the initial flow q. i *(1-s), the flow of branch j is updated to the initial flow q j *(1+s), s is the calculation step length, which is 0.01-0.1; if the total resistance of branch i is less than the total resistance of branch j, the flow of branch i is the initial flow q i *(1+s), the flow of branch j is updated to the initial flow q j *(1-s); Repeat the calculation until the total resistance of branch i - the total resistance of branch j = 0±u, where u is the convergence error value. Record the flow data of each branch at this time and the resistance components in the branch that meet the algorithm conditions.

4. The multi-branch flow distribution method for a cooling system in an aircraft thermal environment according to claim 3, characterized in that: For branches with similar temperature, flow and resistance characteristics, the calculation of such branches can be omitted, and the theoretical required flow of the omitted branches can be subtracted from the total flow.

5. The multi-branch flow distribution method for a cooling system in an aircraft thermal environment according to claim 1, characterized in that: A flow-resistance test platform is built in the order of the flow deviation n of a single branch to verify the theoretical group of resistance components.

6. The multi-branch flow distribution method for a cooling system in an aircraft thermal environment according to claim 1, characterized in that: The flow control valve is a flow control valve with multi-stage resistance adjustment or continuous resistance adjustment.

7. The multi-branch flow distribution method for a cooling system in an aircraft thermal environment according to claim 1, characterized in that: The resistance value of the flow control valve is randomly set within 0-150% of the resistance variation design range of each branch.

8. The multi-branch flow distribution method for a cooling system in an aircraft thermal environment according to claim 1, characterized in that: The minimum value, the middle value and the maximum value are selected from the resistance variation design range of 0-150% of each branch, and the flow control valve is adjusted so that the total resistance of each branch randomly meets the minimum value, the middle value and the maximum value setting of the corresponding branch.

9. The multi-branch flow distribution method for a cooling system in an aircraft thermal environment according to claim 8, characterized in that: The resistance value of the branch with a distribution coefficient above 1.1 is preferentially set to the maximum value, and the total resistance of the remaining branches randomly meets the minimum, middle and maximum values ​​of the corresponding branches.

10. The multi-branch flow distribution method for a cooling system in an aircraft thermal environment according to claim 1, characterized in that: The test results show that there are multiple groups of resistance component practice groups that meet the screening conditions. One of the groups is selected in turn according to cooling effect, pipeline pressure and processing difficulty to be installed in the aircraft.

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