A 3D printing-based regenerative cooling engine abnormal channel heat transfer evaluation method

Abstract

The application relates to a 3D printing-based abnormal cooling channel heat transfer evaluation method of a regenerative cooling engine, which comprises the following steps: determining an overheating area of a thrust chamber, obtaining node overheating temperature of an overheating position; carrying out heat transfer calculation of a normal cooling channel of the thrust chamber and obtaining a gas side theoretical normal wall temperature of the overheating position; assuming an initial coolant flow value of the overheating position, carrying out abnormal cooling channel heat transfer calculation to obtain a theoretical node overheating temperature; judging whether the theoretical node overheating temperature and the node overheating temperature meet a condition; if yes, taking the initial coolant flow value as a final coolant flow value; obtaining a coolant flow variation ratio alpha based on the final coolant flow value, obtaining a rated working condition flow of the abnormal cooling channel, carrying out abnormal cooling channel heat transfer calculation and evaluation, and outputting a rated abnormal cooling channel gas side wall temperature; and if the rated abnormal cooling channel gas side wall temperature is lower than a material temperature resistance limit of the thrust chamber, the rated working condition of a hot test is safe, and the test can be carried out.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine cooling, and particularly relates to a heat transfer evaluation method for abnormal channel of regenerative cooling engine based on 3D printing. BACKGROUND

[0002] The structure of a liquid rocket engine has characteristics of flexible processing, small batch, thin wall, complex topology and high cost. By using additive manufacturing technology, the process limitations of traditional subtractive manufacturing can be broken through, and the manufacturing technical problems caused by complex assembly operation, complex internal features and high-performance assembly integration can be reduced, and the complex welding and other connection operations and the number of parts can be reduced. Compared with the processing period of 12-18 months of the traditional engine combustion chamber, the processing period can be shortened to 3-5 months by using additive manufacturing technology.

[0003] However, the current additive manufacturing technology still has some deficiencies. For a liquid rocket engine, the gas temperature in the combustion chamber during operation can exceed 3000K. In order to avoid the ablation of the thrust chamber, the regenerative cooling technology is often used, which uses propellant as coolant to flow through the cooling flow channel on the body of the combustion chamber for cooling. There are hundreds of cooling flow channels on the body of the engine, and the hydraulic diameter of each flow channel is in the order of millimeters. For the complex small-size flow channel of additive manufacturing, there may be semi-sintered powder agglomeration in the hole, which will block the fluid flow in the flow channel. In addition, if debris falls into the flow channel during subsequent machining process, it will also be difficult to flush out. At present, there are still great difficulties in cleaning and mechanical polishing treatment of the complex small-size internal flow channel of additive manufacturing. When foreign matter appears in the cooling channel, the flow resistance of the coolant in the flow channel will increase, and the coolant flow in the abnormal cooling channel will decrease, and the cooling effect will decrease, which may cause the ablation of the inner wall of the thrust chamber and directly affect the service life of the engine. Therefore, it is very important to evaluate the heat transfer process of the abnormal cooling channel for the selection of safe working conditions of the engine with abnormal cooling channel. In addition, the reusable rocket engine has a limited number of uses. By establishing a heat transfer evaluation method for abnormal channel of regenerative cooling engine based on 3D printing, the number of ground thermal tests can be effectively reduced, and the actual number of uses of the rocket engine can be improved, and the cost of launching the rocket can be reduced.

[0004] Therefore, it is necessary to establish a heat transfer evaluation method for abnormal channel of regenerative cooling engine based on 3D printing, so as to evaluate the overheating risk of the abnormal cooling channel of the engine and provide support for the selection of safe operation conditions of the engine, which has become a problem to be solved by those skilled in the art. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a heat transfer evaluation method for abnormal channel of regenerative cooling engine based on 3D printing.

[0006] To achieve the above-mentioned purpose, the present invention provides a 3D printing-based method for evaluating heat transfer in abnormal channels of a regenerative cooling engine. A hot run test is conducted on a rocket engine under preset safety conditions and a heat transfer evaluation is performed after the hot run test is completed. The method comprises the following steps:

[0007] S1. After completing the hot start test under safe working conditions, determine the overheating area of ​​the thrust chamber of the rocket engine, and identify the overheating temperature of the overheating area to obtain the overheating position node a Node overheat temperature T wg ( a );

[0008] S2. Based on the safe working conditions of the hot-start test, the heat transfer calculation of the normal cooling channel of the thrust chamber is carried out and the overheating position node is obtained. a Theoretical normal wall temperature on the gas side T wg_n ( a );

[0009] S3. Assumed overheating location node a The initial value of the first coolant flow rate of the abnormal cooling channel at m' , based on the initial value of the first coolant flow rate m' Carry out abnormal cooling channel heat transfer calculation to obtain the overheating location node a Theoretical node superheat temperature at T' wg ( a );Determine the theoretical node overheat temperature T' wg ( a ) and the node overheat temperature T wg ( a ) whether the preset conditions are met; if so, the first coolant flow initial value m' Final coolant flow as abnormal cooling channel m ;

[0010] S4. Final coolant flow based on abnormal cooling channels m Obtain the coolant flow change ratio α between the abnormal cooling channel and the normal cooling channel, and the rated operating flow of the normal cooling channel under rated operating conditions. m RPL,n The rated operating flow of the abnormal cooling channel is obtained by adding the flow change ratio α m RPL , and based on the rated operating flow of the abnormal cooling channel m RPL Carry out abnormal cooling channel heat transfer calculation and evaluation, and output the rated abnormal cooling channel gas side wall temperature Twg_AOC ;

[0011] If the rated abnormal cooling channel gas side wall temperature T wg_AOC Lower than the temperature limit T of the material of the thrust chamber wg_limit , then the rated operating conditions of the hot car test are safe and the test run can be carried out;

[0012] If the rated abnormal cooling channel gas side wall temperature T wg_AOC Higher than the temperature limit T of the material of the thrust chamber wg_limit , then replace the rated operating conditions of the hot car test and repeat step S4 to carry out abnormal cooling channel heat transfer calculation and evaluation until the rated operating conditions of the hot car test are safe.

[0013] According to one aspect of the present invention, in step S1, the overheating temperature of the overheating area is identified to obtain the overheating position node a Node overheat temperature T wg ( a ) step, a spectrophotometer is used to measure the color difference between the overheated area and the standard sample to determine the overheated position node a Node overheat temperature T wg ( a ).

[0014] According to one aspect of the present invention, in step S2, the heat transfer calculation of the normal cooling channel of the thrust chamber is carried out based on the safe working condition of the hot car test and the overheating position node is obtained. a Theoretical normal wall temperature on the gas side T wg_n ( a ) steps, including:

[0015] S21. Input the safety operating condition parameters involved in the hot-run test safety operating conditions. These safety operating condition parameters include the thrust chamber safe operating condition inlet conditions and the normal cooling channel safe operating condition inlet conditions. The thrust chamber safe operating condition inlet conditions include the safe operating condition gas flow rate and the safe operating condition thrust chamber pressure. The normal cooling channel safe operating condition inlet conditions include the safe operating condition coolant inlet pressure, the safe operating condition coolant inlet temperature, and the safe operating condition normal cooling channel coolant flow rate.

[0016] S22. Based on the safety operating condition parameters, perform thrust chamber regenerative cooling heat transfer calculations and output the overheating position node. a Theoretical normal wall temperature on the gas side T wg_n ( a ).

[0017] According to one aspect of the present invention, in step S22, the step of performing thrust chamber regenerative cooling heat transfer calculation based on the safety operating condition parameters includes:

[0018] S221. Obtain the structural parameters of the thrust chamber and divide the thrust chamber into multiple microelements along the axial direction;

[0019] S222. Based on the thrust chamber safe operating condition inlet conditions and the preset combustion chamber temperature field calculation model, solve the safe operating condition gas parameters at any infinitesimal position; wherein, the safe operating condition gas parameters include: Mach number of the gas Ma , Gas side insulation wall temperature T aw and gas side convective heat transfer coefficient h gas ;

[0020] The gas side convection heat transfer coefficient h gas It is obtained according to the semi-empirical Bartz formula and is expressed as:

[0021] ;

[0022] ;

[0023] in, is the diameter of the thrust chamber throat, is the dynamic viscosity of the gas at the stagnation temperature, is the specific heat of gas at constant pressure, is the gas Prandtl number, is the thrust chamber pressure, is the thrust chamber characteristic velocity, is the qualitative temperature variation coefficient, is the throat curvature radius, , are the throat area and the cross-sectional area of ​​the segment respectively, is the thrust chamber temperature, is the gas specific heat ratio, is the Mach number of the gas, subscript is the hysteresis parameter, is the gas side wall temperature;

[0024] S223. Assume that i The gas side wall temperature at the microelement , and solve the first i Heat flux density under safe working condition at infinitesimal point , among which, i =1 microelement is at the normal cooling channel entrance position;

[0025] The heat flux density under safe working condition Expressed as:

[0026] ;

[0027] S224. Obtain normal cooling channel parameters and the normal cooling channel entrance safety conditions, wherein the normal cooling channel parameters include: channel width, channel height, rib width, and number of channels at any microelement;

[0028] S225. Based on the heat flux density of the safety working condition , carry out thermodynamic and hydraulic calculation of coolant in normal cooling channel, and obtain the i Coolant temperature under safe operating conditions at the infinitesimal point and safe operating condition coolant side wall temperature ; Wherein, the safe operating condition coolant temperature and the coolant side wall temperature under the safe operating condition Respectively expressed as:

[0029] ;

[0030] ;

[0031] in, is the thickness of the inner wall of the thrust chamber, that is, the thickness of the wall between the coolant and the gas, is the thermal conductivity of the material, is the coolant side convective heat transfer coefficient, is the total efficiency of the rib surface;

[0032] S226. Based on the safe working condition coolant side wall temperature , using the preset thrust chamber wall heat conduction model, solve the i Normal cooling channel gas side wall temperature at microelement ; Wherein, the normal cooling channel gas side wall temperature Expressed as:

[0033] ;

[0034] S227. Calculate the assumed gas side wall temperature and normal cooling channel gas side wall temperature If the relative error is less than or equal to the preset threshold, the i Heat flux density under safe working condition at infinitesimal point , gas side wall temperature , Normal cooling channel gas side wall temperature The coupled solution converges and the last calculated safety condition heat flux density is converted to 、 Gas side wall temperature , Normal cooling channel gas side wall temperature For the i The final parameter at the infinitesimal point;

[0035] S228. Complete i After the calculation at the infinitesimal point, i Safe operating coolant temperature at +1 microelement and safe operating coolant pressure The calculation is as follows:

[0036] ;

[0037] ;

[0038] in, 、 、 、 Respectively i The heat flux density of the safe working condition at each microelement, the heat exchange area on the gas side, the length of the cooling channel, the hydraulic diameter of the cooling channel, is the coolant flow rate of the normal channel under safe working conditions, is the specific heat capacity of the coolant, is the friction coefficient, For coolant dense flow, is the coolant density, For the i The coolant temperature of the safe working condition at the infinitesimal point is, For the i Coolant pressure in safe working condition at the microelement;

[0039] Based on the iterative solution of steps S222 to S227, the heat flux density of the safe working condition along the normal cooling channel of the entire thrust chamber is obtained. , gas side wall temperature , Normal cooling channel gas side wall temperature , safe working condition coolant side wall temperature , safe operating coolant temperature and safe operating coolant pressure .

[0040] According to one aspect of the present invention, in step S225, the coolant side convective heat transfer coefficient The heat transfer correlation is obtained by selecting a corresponding heat transfer correlation based on the coolant phase and the flow Reynolds number, wherein the coolant phase is one of gas, liquid, gas-liquid two-phase state, and supercritical state.

[0041] According to one aspect of the present invention, in step S3, it is assumed that the overheating position node a The initial value of the first coolant flow rate of the abnormal cooling channel at m' , based on the initial value of the first coolant flow rate m' Carry out abnormal cooling channel heat transfer calculation to obtain the overheating location node a Theoretical node superheat temperature at T' wg ( a ) step, the first coolant flow initial value m' Expressed as:

[0042] m' = T wg_n ( a ) / T wg ( a )× m _n；

[0043] in, m _n is the coolant flow rate of the normal cooling channel.

[0044] According to one aspect of the present invention, in step S3, the theoretical node overheat temperature is determined. T' wg ( a ) and the node overheat temperature T wg ( a ) satisfies the preset conditions, if not, iteratively optimize the first coolant flow initial value m' The abnormal cooling channel heat transfer calculation is carried out again until the theoretical node overheating temperature T' wg ( a ) and the node overheat temperature T wg ( a ) satisfies the preset conditions, and the first coolant flow initial value after iterative optimization is m' Final coolant flow as abnormal cooling channel m ; Wherein, the initial value of the first coolant flow rate m' Based on theoretical node overheat temperature T' wg ( a ) and node overheat temperature T wg ( a ) is iteratively optimized and expressed as:

[0045] ;

[0046] The preset conditions are:

[0047] ;

[0048] in, ε is the preset threshold.

[0049] According to one aspect of the present invention, in step S3, it is assumed that the overheating position node a The initial value of the first coolant flow rate of the abnormal cooling channel at m' , based on the initial value of the first coolant flow rate m' Carry out abnormal cooling channel heat transfer calculation to obtain the overheating location node a Theoretical node superheat temperature at T' wg ( a ) steps, including:

[0050] S31. Obtaining structural parameters of the abnormal cooling channel and dividing the channel into multiple micro-elements along the abnormal cooling channel;

[0051] S32. Solve the safe working condition gas parameters at any slot microelement based on the thrust chamber safe working condition inlet conditions and the preset combustion chamber temperature field calculation model; wherein, the safe working condition gas parameters include: the Mach number of the gas Ma , Gas side insulation wall temperature T aw and gas side convective heat transfer coefficient h gas ;

[0052] The gas side convection heat transfer coefficient h gas It is obtained according to the semi-empirical Bartz formula and is expressed as:

[0053] ;

[0054] ;

[0055] in, is the diameter of the thrust chamber throat, is the dynamic viscosity of the gas at the stagnation temperature, is the specific heat of gas at constant pressure, is the gas Prandtl number, is the thrust chamber pressure, is the thrust chamber characteristic velocity, is the qualitative temperature variation coefficient, is the throat curvature radius, , are the throat area and the cross-sectional area of ​​the segment respectively, is the thrust chamber temperature, is the gas specific heat ratio, is the Mach number of the gas, is the hysteresis parameter, is the gas side wall temperature;

[0056] S33. Assume that j Abnormal cooling gas side wall temperature at each channel microelement , and solve the first j Abnormal cooling channel heat flux density at each channel element , among which, j = 1 channel element is located at the abnormal cooling channel entrance;

[0057] Then, the abnormal cooling channel heat flux density Expressed as:

[0058] ;

[0059] S34. Obtain abnormal cooling channel parameters and abnormal cooling channel inlet conditions, wherein the abnormal cooling channel parameters include: channel width, channel height, rib width, and number of channels at any channel microelement; the abnormal cooling channel inlet conditions include: coolant inlet pressure, coolant inlet temperature, and initial value of the first coolant flow rate. m' ;

[0060] S35. Based on abnormal cooling channel heat flux , carried out thermal and hydraulic calculation of coolant in abnormal cooling channel, and obtained the j Abnormal cooling channel coolant temperature at each channel element and abnormal cooling channel coolant side wall temperature ; Wherein, the abnormal cooling channel coolant temperature and the abnormal cooling channel coolant side wall temperature Respectively expressed as:

[0061] ;

[0062] ;

[0063] in, is the thickness of the inner wall of the thrust chamber, that is, the thickness of the wall between the coolant and the gas, is the thermal conductivity of the material, is the coolant side convective heat transfer coefficient, is the total efficiency of the rib surface;

[0064] S36. Based on the abnormal cooling channel coolant side wall temperature , using the preset thrust chamber wall heat conduction model, solve the j Abnormal cooling channel gas side wall temperature at each channel microelement ; Wherein, the abnormal cooling channel gas side wall temperature Expressed as:

[0065] ;

[0066] S37. Calculate the assumed abnormal cooling gas side wall temperature and abnormal cooling channel gas side wall temperature If the relative error is less than or equal to the preset threshold, the j Abnormal cooling channel heat flux density at each channel element , Abnormal cooling gas side wall temperature , Abnormal cooling channel gas side wall temperature The coupled solution converges and the abnormal cooling channel heat flux calculated last time is converted to 、 Abnormal cooling channel gas side wall temperature For the j The final parameters at each infinitesimal channel;

[0067] S38. Complete j After calculating the position of each slot element, j The parameters at the infinitesimal element of the channel are used as the j +1 channel microelement entrance conditions, and based on the iterative solution according to steps S32 to S37, obtain the abnormal cooling channel heat flux density along the entire abnormal cooling channel under safe working conditions , Abnormal cooling channel gas side wall temperature , Abnormal cooling channel coolant side wall temperature , Abnormal cooling channel coolant temperature and abnormal cooling channel coolant pressure .

[0068] According to one aspect of the present invention, in step S4, the final coolant flow rate of the abnormal cooling channel is m In the step of obtaining a coolant flow change ratio α between the abnormal cooling channel and the normal cooling channel, the coolant flow change ratio α is expressed as:

[0069] α= m / m _n；

[0070] in, m _n is the coolant flow rate of the normal cooling channel;

[0071] In step S4, based on the rated working condition flow rate of the normal cooling channel under rated working conditions m RPL,n The rated operating flow of the abnormal cooling channel is obtained by adding the flow change ratio α m RPL In the step of m RPL Expressed as:

[0072] m RPL= α× m RPL,n .

[0073] According to one aspect of the present invention, in step S4, based on the rated operating flow of the abnormal cooling channel m RPL The steps for conducting abnormal cooling channel heat transfer calculation evaluation include:

[0074] S41. Obtaining structural parameters of the abnormal cooling channel and dividing the abnormal cooling channel into multiple channel microelements;

[0075] S42. Based on the preset thrust chamber rated operating condition inlet conditions and the preset combustion chamber temperature field calculation model, the rated operating condition gas parameters at any slot microelement are solved; wherein, the thrust chamber rated operating condition inlet conditions include: rated operating condition gas flow rate and rated operating condition thrust chamber pressure, and the rated operating condition gas parameters include: Mach number of the gas Ma , Gas side insulation wall temperature T aw and gas side convective heat transfer coefficient h gas ;

[0076] The gas side convection heat transfer coefficient h gas It is obtained according to the semi-empirical Bartz formula and is expressed as:

[0077] ;

[0078] ;

[0079] in, is the diameter of the thrust chamber throat, is the dynamic viscosity of the gas at the stagnation temperature, is the specific heat of gas at constant pressure, is the gas Prandtl number, is the thrust chamber pressure, is the thrust chamber characteristic velocity, is the qualitative temperature variation coefficient, is the throat curvature radius, , are the throat area and the cross-sectional area of ​​the segment respectively, is the thrust chamber temperature, is the gas specific heat ratio, is the Mach number of the gas, is the hysteresis parameter, is the gas side wall temperature;

[0080] S43. Assume that k Rated abnormal cooling gas side wall temperature at each channel microelement , and solve the first k Rated operating channel heat flux density at each channel element , among which, k = 1 channel element is located at the abnormal cooling channel entrance;

[0081] The rated operating channel heat flux density Expressed as:

[0082] ;

[0083] S44. Obtain abnormal cooling channel parameters and abnormal cooling channel rated working condition inlet conditions, wherein the abnormal cooling channel parameters include: channel width, channel height, rib width, and number of channels at any channel microelement; the abnormal cooling channel rated working condition inlet conditions include: rated working condition coolant inlet pressure, rated working condition coolant inlet temperature, and rated working condition flow rate of the abnormal cooling channel. m RPL ;

[0084] S45. Based on rated operating conditions slot heat flux , carried out thermal and hydraulic calculation of coolant in abnormal cooling channel, and obtained the k Rated operating coolant temperature at each channel element and rated operating coolant side wall temperature ; Wherein, the rated operating coolant temperature and the rated operating coolant side wall temperature Respectively expressed as:

[0085] ;

[0086] ;

[0087] in, is the thickness of the inner wall of the thrust chamber, that is, the thickness of the wall between the coolant and the gas, is the thermal conductivity of the material, is the coolant side convective heat transfer coefficient, is the total efficiency of the rib surface;

[0088] S46. Based on the rated operating condition coolant side wall temperature , using the preset thrust chamber wall heat conduction model, solve the k The abnormal cooling channel gas side wall temperature at the rated working condition at each channel microelement ; Among them, the rated working condition abnormal cooling channel gas side wall temperature Expressed as:

[0089] ;

[0090] S47. Calculate the assumed rated abnormal cooling gas side wall temperature and rated working condition abnormal cooling channel gas side wall temperature If the relative error is less than or equal to the preset threshold, the k The heat flux density of the slot at the rated working condition at each slot element , Rated abnormal cooling gas side wall temperature , Abnormal cooling channel gas side wall temperature under rated working conditions The coupled solution converges and the last calculated rated working condition channel heat flux density is converted to 、 Abnormal cooling channel gas side wall temperature under rated operating conditions For the k The final parameters at each infinitesimal channel;

[0091] S48. Complete k After calculating the position of each slot element, k The parameters at the infinitesimal element of the channel are used as the k +1 channel microelement entrance conditions, and based on the iterative solution according to steps S42 to S47, obtain the rated working condition channel heat flux density along the entire abnormal cooling channel , Abnormal cooling channel gas side wall temperature under rated operating conditions , rated operating condition coolant side wall temperature , Rated operating coolant temperature and rated operating coolant pressure .

[0092] According to one solution of the present invention, this solution addresses the risk of flow reduction caused by foreign matter blockage in the grooves during additive manufacturing engine processing, which in turn causes abnormal engine groove overheating. It can effectively assess the impact of foreign matter blockage on flow reduction, accurately determine the effect of thermal protection on the inner wall of the engine, and fully avoid the occurrence of engine ablation or even explosion due to failure of thermal protection.

[0093] According to a solution of the present invention, this solution can perform cyclic iterative calculations on each divided microelement position along the different cooling channels, effectively ensuring that the calculation results of each upstream position are more in line with the actual state, making the calculation results along the process of this solution converge more accurately, and making the evaluation effect of this solution more excellent.

[0094] According to one solution of the present invention, for a rocket engine with abnormal cooling groove processing, this solution can accurately determine the safe operating conditions of the engine, thereby realizing the reuse of the rocket engine and effectively saving resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Figure 1 A diagram showing the steps of a method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to an embodiment of the present invention;

[0096] Figure 2 This is a partial surface diagram of a thrust chamber after a hot-start test is completed according to an embodiment of the present invention;

[0097] Figure 3 A standard sample diagram for an embodiment of the present invention;

[0098] Figure 4 This is a microelement node partitioning diagram for thrust chamber regenerative cooling heat transfer calculation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0099] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not limited to the following embodiments.

[0100] like Figure 1 As shown, according to one embodiment of the present invention, a 3D printing-based regenerative cooling engine abnormal channel heat transfer evaluation method of the present invention conducts a hot run test on a rocket engine under preset safety conditions and performs a heat transfer evaluation after the hot run test is completed, which includes the following steps:

[0101] S1. After completing the hot start test under safe working conditions, determine the overheating area of ​​the thrust chamber of the rocket engine, and identify the overheating temperature of the overheating area to obtain the node overheating temperature at the overheating position node a. T wg ( a );

[0102] S2. Based on the safe operating conditions of the hot-run test, perform heat transfer calculations on the normal cooling channels of the thrust chamber and obtain the overheating location nodes. a Theoretical normal wall temperature on the gas side T wg_n ( a);

[0103] S3. Assumed overheating location node a The initial value of the first coolant flow rate of the abnormal cooling channel at m' , based on the initial value of the first coolant flow m' Carry out abnormal cooling channel heat transfer calculation to obtain the overheating location node a Theoretical node superheat temperature at T' wg ( a ) ; Determine theoretical node overheat temperature T' wg ( a ) and node overheat temperature T wg ( a ) whether the preset conditions are met; if so, the initial value of the first coolant flow rate is m' Final coolant flow as abnormal cooling channel m ;

[0104] S4. Final coolant flow rate based on abnormal cooling channels m Obtain the coolant flow change ratio α between the abnormal cooling channel and the normal cooling channel, and the rated operating flow of the normal cooling channel under rated operating conditions. m RPL,n The rated operating flow of the abnormal cooling channel is obtained by adding the flow change ratio α m RPL , and based on the rated operating flow of the abnormal cooling channel m RPL Carry out abnormal cooling channel heat transfer calculation and evaluation, and output the rated abnormal cooling channel gas side wall temperature T wg_AOC ;

[0105] If the rated abnormal cooling channel gas side wall temperature T wg_AOC Lower than the temperature limit T of the thrust chamber material wg_limit , then the rated operating conditions of the hot car test are safe and the test run can be carried out;

[0106] If the rated abnormal cooling channel gas side wall temperature T wg_AOC Higher than the temperature limit T of the material of the thrust chamber wg_limit , then replace the rated operating conditions of the hot car test and repeat step S4 to carry out abnormal cooling channel heat transfer calculation and evaluation until the rated operating conditions of the hot car test are safe.

[0107] According to one embodiment of the present invention, in the process of conducting a hot-start test of a rocket engine under a preset safe operating condition, since a safety assessment of the operating condition has not yet been performed, a lower safe operating condition can be selected for the hot-start test, so that a subsequent heat transfer assessment can be performed to obtain a qualified operating condition for safe testing.

[0108] According to one embodiment of the present invention, in step S1, in the step of determining the overheating area of ​​the thrust chamber of the rocket engine after completing the hot run test under safe working conditions, since the thrust chamber is subjected to the combustion process of the gas after completing the hot run test, the color of the side wall of the thrust chamber will change differently. Specifically, during the test, it is necessary to pass coolant into the cooling channel of the side wall of the thrust chamber to cool the side wall. However, if the cooling is uneven, the high temperature area and the low temperature area will show different color changes after complete cooling. See Figure 2 Furthermore, visual inspection of the outer wall of the thrust chamber can obtain the overheating area of ​​the thrust chamber.

[0109] In this embodiment, in step S1, the overheating temperature of the overheating area is identified to obtain the overheating position node. a Node overheat temperature T wg ( a ) step, a spectrophotometer is used to measure the color difference between the overheating area and the standard sample to determine the overheating location node. a Node overheat temperature T wg ( a ). Furthermore, the standard sample can be formed based on a pre-prepared method, wherein, first, a plurality of standard sample blanks of the same size and regular shape are prepared, wherein the material of the standard sample blank is consistent with the material of the side wall of the thrust chamber; secondly, different standard sample blanks are placed in a high-temperature tube furnace in turn, and the different standard sample blanks are heated at different temperatures and times, and the heated standard sample blanks are placed in a drying box for standby use. In this embodiment, the heating atmosphere for the standard sample blank in the high-temperature tube furnace is consistent with the gas composition burned in the thrust chamber, and the heating temperature and heating time can be linearly arranged within a certain range; thereby, standard samples under different heating times can be obtained, see Figure 3 .

[0110] In this embodiment, when identifying the overheating temperature of the overheating area, a standard sample formed under the same or similar state as the hot car test time is selected for comparison with the overheating area, so as to determine the closest standard sample, and then the temperature of the overheating area can be obtained. The side wall of the thrust chamber can be meshed in advance, thereby obtaining the selected overheating position node. a Node overheat temperature T wg ( a );

[0111] According to one embodiment of the present invention, in step S2, the heat transfer calculation of the normal cooling channel of the thrust chamber is carried out based on the safe working condition of the hot car test and the overheating position node is obtained. a Theoretical normal wall temperature on the gas side T wg_n ( a ) steps, including:

[0112] S21. Input the safety operating condition parameters involved in the hot-run test safety operating conditions. The safety operating condition parameters include the thrust chamber safe operating condition inlet conditions and the normal cooling channel safe operating condition inlet conditions. The thrust chamber safe operating condition inlet conditions include the safe operating condition gas flow rate and the safe operating condition thrust chamber pressure. The normal cooling channel safe operating condition inlet conditions include the safe operating condition coolant inlet pressure, the safe operating condition coolant inlet temperature, and the safe operating condition normal cooling channel coolant flow rate.

[0113] S22. Perform thrust chamber regenerative cooling heat transfer calculation based on safety operating condition parameters and output overheating position nodes a Theoretical normal wall temperature on the gas side T wg_n ( a ).

[0114] In this embodiment, in step S22, the step of performing thrust chamber regenerative cooling heat transfer calculation based on the safety operating condition parameters includes:

[0115] S221. Obtain the structural parameters of the thrust chamber and divide the thrust chamber into multiple microelements along the axial direction. Figure 4 In this embodiment, the structural parameters of the thrust chamber can be collected according to the specific structure of the thrust chamber or obtained by pre-collection.

[0116] S222. Based on the thrust chamber safe operating condition inlet conditions and the preset combustion chamber temperature field calculation model, solve the safe operating condition gas parameters at any infinitesimal location; wherein, the combustion chamber temperature field calculation model is calculated by the thrust chamber aerodynamic basic equations, including the energy conservation equation, the gas state equation, the mass conservation equation, the isentropic flow process equation, the momentum equation, etc., which are well known in the art and will not be described in detail here. Further, the safe operating condition gas parameters include: the Mach number of the gas Ma , Gas side insulation wall temperature T aw and gas side convective heat transfer coefficient h gas In this embodiment, the gas side convection heat transfer coefficient h gas It is obtained according to the semi-empirical Bartz formula and expressed as:

[0117] ;

[0118] ;

[0119] in, is the diameter of the thrust chamber throat, is the dynamic viscosity of the gas at the stagnation temperature, is the specific heat of gas at constant pressure, is the gas Prandtl number, is the thrust chamber pressure, is the thrust chamber characteristic velocity, is the qualitative temperature variation coefficient, is the throat curvature radius, , are the throat area and the cross-sectional area of ​​the segment respectively, is the thrust chamber temperature, is the gas specific heat ratio, is the Mach number of the gas, subscript is the hysteresis parameter, is the gas side wall temperature;

[0120] S223. Assume that i The gas side wall temperature at the microelement , and solve the first i Heat flux density under safe working condition at infinitesimal point , among which, i = 1 microelement is at the normal cooling channel entrance position; in this embodiment, the heat flux density under safe working condition Expressed as:

[0121] ;

[0122] S224. Obtain normal cooling channel parameters and normal cooling channel inlet safety conditions, where normal cooling channel parameters include: channel width, channel height, rib width, and number of channels at any microelement; based on the normal cooling channel parameters, solve for parameters such as the cooling channel hydraulic diameter and rib efficiency;

[0123] S225. Based on heat flux density under safe working conditions , carry out thermodynamic and hydraulic calculation of coolant in normal cooling channel, and obtain the i Coolant temperature under safe operating conditions at the infinitesimal point and safe operating condition coolant side wall temperature ; Among them, the safe operating coolant temperature and safe operating condition coolant side wall temperature Respectively expressed as:

[0124] ;

[0125] ;

[0126] in, is the thickness of the inner wall of the thrust chamber, that is, the thickness of the wall between the coolant and the gas, is the thermal conductivity of the material, is the coolant side convective heat transfer coefficient, is the total efficiency of the rib surface;

[0127] In this embodiment, the coolant side convective heat transfer coefficient h co The corresponding heat transfer correlation is obtained by selecting the corresponding heat transfer correlation based on the coolant phase and the flow Reynolds number, which will not be repeated here; wherein the coolant phase is one of gas, liquid, gas-liquid two-phase state, and supercritical state.

[0128] S226. Coolant side wall temperature based on safe working condition , using the preset thrust chamber wall heat conduction model, solve the i Normal cooling channel gas side wall temperature at microelement ; Among them, the thrust chamber inner wall heat conduction model is calculated by the thrust chamber aerodynamic basic equations, including the energy conservation equation, gas state equation, mass conservation equation, isentropic flow process equation, momentum equation, etc., which are well known in the art and will not be described here. Expressed as:

[0129] ;

[0130] S227. Calculate the assumed gas side wall temperature and normal cooling channel gas side wall temperature If the relative error is less than or equal to the preset threshold, the i Heat flux density under safe working condition at infinitesimal point , gas side wall temperature , Normal cooling channel gas side wall temperature The coupled solution converges and the last calculated safety condition heat flux density is converted to 、 Gas side wall temperature , Normal cooling channel gas side wall temperature For the i The final parameter at the infinitesimal point;

[0131] S228. Complete i After the calculation at the infinitesimal point, i Safe operating coolant temperature at +1 microelement and safe operating coolant pressure The calculation is as follows:

[0132] ;

[0133] ;

[0134] in, 、 、 、 Respectively i The heat flux density of the safe working condition at each microelement, the heat exchange area on the gas side, the length of the cooling channel, the hydraulic diameter of the cooling channel, is the coolant flow rate of the normal channel under safe working conditions, is the specific heat capacity of the coolant, is the friction coefficient, For coolant dense flow, is the coolant density, For the i The coolant temperature of the safe working condition at the infinitesimal point is, For the i The safe operating coolant pressure at the infinitesimal point is, as can be understood, i =1, it is at the normal cooling channel inlet position, then the safe operating coolant pressure at the first infinitesimal element is the coolant inlet safety pressure.

[0135] Based on the iterative solution of steps S222 to S227, the heat flux density of the safe working condition along the normal cooling channel of the entire thrust chamber is obtained. , gas side wall temperature , Normal cooling channel gas side wall temperature , safe working condition coolant side wall temperature , safe operating condition coolant temperature and safe operating coolant pressure .

[0136] In this embodiment, based on the obtained gas side wall temperature along the normal cooling channel of the thrust chamber, You can get the overheating position node a The corresponding gas side wall temperature value is used as the superheating position node a Theoretical normal wall temperature on the gas side T wg_n ( a ).

[0137] According to one embodiment of the present invention, in step S3, it is assumed that the overheating position node a The initial value of the first coolant flow rate of the abnormal cooling channel at m' , based on the initial value of the first coolant flow m' Carry out abnormal cooling channel heat transfer calculation to obtain the overheating location nodea theoretical node superheat temperature T' wg ( a ) in step S2 m' is expressed as:

[0138] m' = T wg_n ( a ) / T wg ( a )× m _n；

[0139] wherein, m _n is the coolant flow rate of the normal cooling channel.

[0140] According to an embodiment of the present application, in step S3, the step of judging whether the theoretical node superheat temperature T' wg ( a ) and the node superheat temperature T wg ( a ) satisfy the preset condition, if not, the first coolant flow rate initial value m' is iteratively optimized and the abnormal cooling channel heat transfer calculation is re-performed until the theoretical node superheat temperature T' wg ( a ) and the node superheat temperature T wg ( a ) satisfy the preset condition, and the first coolant flow rate initial value m' after the iterative optimization is taken as the final coolant flow rate m of the abnormal cooling channel; wherein the first coolant flow rate initial value m' is iteratively optimized based on the theoretical node superheat temperature T' wg ( a ) and the node superheat temperature T wg ( a ), and is expressed as:

[0141] ;

[0142] In the present embodiment, based on the above formula, the first coolant flow rate initial value m' is optimized once, then the abnormal cooling channel heat transfer calculation is re-performed with the first coolant flow rate initial value m' after the optimization until the corresponding preset condition is reached to terminate. Further, the preset condition set is:

[0143] ;

[0144] in, ε is the preset threshold.

[0145] According to one embodiment of the present invention, in step S3, it is assumed that the overheating position node a The initial value of the first coolant flow rate of the abnormal cooling channel at m' , based on the initial value of the first coolant flow m' Carry out abnormal cooling channel heat transfer calculation to obtain the overheating location node a Theoretical node superheat temperature at T' wg ( a ) steps, including:

[0146] S31. Obtaining structural parameters of the abnormal cooling channel and dividing the channel into multiple micro-elements along the abnormal cooling channel;

[0147] S32. Based on the thrust chamber safe operating condition inlet conditions and the preset combustion chamber temperature field calculation model, solve the safe operating condition gas parameters at any slot microelement; wherein the safe operating condition gas parameters include: the Mach number of the gas Ma , Gas side insulation wall temperature T aw and gas side convective heat transfer coefficient h gas In this embodiment, the gas side convection heat transfer coefficient h gas It is obtained according to the semi-empirical Bartz formula and expressed as:

[0148] ;

[0149] ;

[0150] in, is the diameter of the thrust chamber throat, is the dynamic viscosity of the gas at the stagnation temperature, is the specific heat of gas at constant pressure, is the gas Prandtl number, is the thrust chamber pressure, is the thrust chamber characteristic velocity, is the qualitative temperature variation coefficient, is the throat curvature radius, , are the throat area and the cross-sectional area of ​​the segment respectively, is the thrust chamber temperature, is the gas specific heat ratio, is the Mach number of the gas, subscript is the hysteresis parameter, is the gas side wall temperature;

[0151] S33. Assume that j Abnormal cooling gas side wall temperature at each channel microelement , and solve the first j Abnormal cooling channel heat flux density at each channel element , among which, j = 1 channel element is at the abnormal cooling channel entrance position; in this embodiment, the abnormal cooling channel heat flux density Expressed as:

[0152] ;

[0153] S34. Obtain abnormal cooling channel parameters and abnormal cooling channel inlet conditions, wherein the abnormal cooling channel parameters include: the channel width, channel height, rib width, and number of channels at any channel microelement; based on the abnormal cooling channel parameters, the hydraulic diameter of the cooling channel, rib efficiency and other parameters are solved; the abnormal cooling channel inlet conditions include: the coolant inlet pressure, the coolant inlet temperature, the initial value of the first coolant flow rate m' ; Used to calculate the coolant side convective heat transfer coefficient of the initial microelement based on the abnormal cooling channel inlet conditions h co and the coolant temperature and pressure of the next infinitesimal element.

[0154] S35. Based on abnormal cooling channel heat flux , carried out thermal and hydraulic calculation of coolant in abnormal cooling channel, and obtained the j Abnormal cooling channel coolant temperature at each channel element and abnormal cooling channel coolant side wall temperature ; Among them, abnormal cooling channel coolant temperature and abnormal cooling channel coolant side wall temperature Respectively expressed as:

[0155] ;

[0156] ;

[0157] in, is the thickness of the inner wall of the thrust chamber, that is, the thickness of the wall between the coolant and the gas, is the thermal conductivity of the material, is the coolant side convective heat transfer coefficient, is the total efficiency of the rib surface;

[0158] S36. Based on abnormal cooling channel coolant side wall temperature , using the preset thrust chamber wall heat conduction model, solve the j Abnormal cooling channel gas side wall temperature at each channel microelement ; Among them, the abnormal cooling channel gas side wall temperature Expressed as:

[0159] ;

[0160] S37. Calculate the assumed abnormal cooling gas side wall temperature and abnormal cooling channel gas side wall temperature If the relative error is less than or equal to the preset threshold, the j Abnormal cooling channel heat flux density at each channel element , Abnormal cooling gas side wall temperature , Abnormal cooling channel gas side wall temperature The coupled solution converges and the abnormal cooling channel heat flux calculated last time is converted to 、 Abnormal cooling channel gas side wall temperature For the j The final parameters at each infinitesimal channel;

[0161] S38. Complete j After calculating the position of each slot element, j The parameters at the infinitesimal element of the channel are used as the j +1 channel microelement entrance conditions, and based on the iterative solution according to steps S32 to S37, obtain the abnormal cooling channel heat flux density along the entire abnormal cooling channel under safe working conditions , Abnormal cooling channel gas side wall temperature , Abnormal cooling channel coolant side wall temperature , Abnormal cooling channel coolant temperature and abnormal cooling channel coolant pressure ; Among them, abnormal cooling channel coolant temperature and abnormal cooling channel coolant pressure The calculation method along the route is consistent with that in the aforementioned step S228 and will not be repeated here.

[0162] According to one embodiment of the present invention, in step S4, based on the final coolant flow of the abnormal cooling channel m In the step of obtaining the coolant flow rate change ratio α between the abnormal cooling channel and the normal cooling channel, the coolant flow rate change ratio α is expressed as:

[0163] α= m / m _n；

[0164] in, m _n is the coolant flow rate of the normal cooling channel;

[0165] Furthermore, the structure of the abnormal cooling channel is consistent regardless of whether it is under a safe operating condition or a rated operating condition. Therefore, the coolant flow rate change ratio α between the abnormal cooling channel and the normal cooling channel under a safe operating condition is also applicable to the rated operating condition. Thus, the rated operating condition of the thrust chamber can be known in advance based on the structural parameters of the thrust chamber. The rated flow rate of the coolant in the abnormal cooling channel relative to the normal cooling channel can be known through the coolant flow rate change ratio α. Then, in step S4, the rated operating condition flow rate of the normal cooling channel under the rated operating condition is determined based on the rated operating condition flow rate of the normal cooling channel. m RPL,n The rated operating flow of the abnormal cooling channel is obtained by adding the flow change ratio α m RPL In the step of m RPL Expressed as:

[0166] m RPL= α× m RPL,n .

[0167] According to one embodiment of the present invention, in step S4, based on the rated operating flow of the abnormal cooling channel m RPL The steps for conducting abnormal cooling channel heat transfer calculation evaluation include:

[0168] S41. Obtaining structural parameters of the abnormal cooling channel and dividing the abnormal cooling channel into multiple channel microelements;

[0169] S42. Based on the preset thrust chamber rated operating condition inlet conditions and the preset combustion chamber temperature field calculation model, solve the rated operating condition gas parameters at any slot microelement; wherein the thrust chamber rated operating condition inlet conditions include: rated operating condition gas flow rate and rated operating condition thrust chamber pressure, and the rated operating condition gas parameters include: Mach number of the gas Ma , Gas side insulation wall temperature T aw and gas side convective heat transfer coefficient h gas In this embodiment, the gas side convection heat transfer coefficient h gas It is obtained according to the semi-empirical Bartz formula and expressed as:

[0170] ;

[0171] ;

[0172] in, is the diameter of the thrust chamber throat, is the dynamic viscosity of the gas at the stagnation temperature, is the specific heat of gas at constant pressure, is the gas Prandtl number, is the thrust chamber pressure, is the thrust chamber characteristic velocity, is the qualitative temperature variation coefficient, is the throat curvature radius, , are the throat area and the cross-sectional area of ​​the segment respectively, is the thrust chamber temperature, is the gas specific heat ratio, is the Mach number of the gas, subscript is the hysteresis parameter, is the gas side wall temperature;

[0173] S43. Assume that k Rated abnormal cooling gas side wall temperature at each channel microelement , and solve the first k Rated operating channel heat flux density at each channel element , among which, k = 1 channel element is at the abnormal cooling channel entrance position; in this embodiment, the rated operating condition rated channel heat flux density Expressed as:

[0174] ;

[0175] S44. Obtain abnormal cooling channel parameters and abnormal cooling channel rated operating condition inlet conditions, wherein the abnormal cooling channel parameters include: channel width, channel height, rib width, and number of channels at any channel microelement; abnormal cooling channel parameters are used to solve parameters such as the hydraulic diameter of the cooling channel and rib efficiency; abnormal cooling channel rated operating condition inlet conditions include: rated operating condition coolant inlet pressure, rated operating condition coolant inlet temperature, and rated operating condition flow rate of the abnormal cooling channel. m RPL ; Based on the abnormal cooling channel rated operating condition inlet conditions, it is used to calculate the coolant side convective heat transfer coefficient of the initial infinitesimal element h co and the coolant temperature and pressure of the next infinitesimal element.

[0176] S45. Based on rated operating conditions slot heat flux , carried out thermal and hydraulic calculation of coolant in abnormal cooling channel, and obtained the k Rated operating coolant temperature at each channel element and rated operating coolant side wall temperature ; Among them, the rated operating coolant temperature and rated operating coolant side wall temperature Respectively expressed as:

[0177] ;

[0178] ;

[0179] in, is the thickness of the inner wall of the thrust chamber, that is, the thickness of the wall between the coolant and the gas, is the thermal conductivity of the material, is the coolant side convective heat transfer coefficient, is the total efficiency of the rib surface;

[0180] S46. Based on rated operating conditions coolant side wall temperature , using the preset thrust chamber wall heat conduction model, solve the k The abnormal cooling channel gas side wall temperature at the rated working condition at each channel microelement ; Among them, the abnormal cooling channel gas side wall temperature under rated working conditions Expressed as:

[0181] ;

[0182] S47. Calculate the assumed rated abnormal cooling gas side wall temperature and rated working condition abnormal cooling channel gas side wall temperature If the relative error is less than or equal to the preset threshold, the k The heat flux density of the slot at the rated working condition at each slot element , Rated abnormal cooling gas side wall temperature , Abnormal cooling channel gas side wall temperature under rated working conditions The coupled solution converges and the last calculated rated working condition channel heat flux density is converted to 、 Abnormal cooling channel gas side wall temperature under rated operating conditions For the k The final parameters at each infinitesimal channel;

[0183] S48. Complete k After calculating the position of each slot element, k The parameters at the infinitesimal element of the channel are used as the k +1 channel microelement entrance conditions, and based on the iterative solution according to steps S42 to S47, obtain the rated working condition channel heat flux density along the entire abnormal cooling channel , Abnormal cooling channel gas side wall temperature under rated working conditions , rated operating condition coolant side wall temperature , Rated operating coolant temperature and rated operating coolant pressure Among them, the rated operating coolant temperature and rated operating coolant pressure The calculation method along the route is consistent with that in the aforementioned step S228 and will not be repeated here.

[0184] In this embodiment, based on the rated working condition abnormal cooling channel gas side wall temperature along the entire abnormal cooling channel under the rated working condition, The rated abnormal cooling channel gas side wall temperature T can be obtained wg_AOC .

[0185] In this embodiment, if the rated abnormal cooling channel gas side wall temperature T wg_AOC Lower than the temperature limit T of the thrust chamber material wg_limit , then the rated operating conditions of the hot engine test are safe and the test can be carried out; if the rated abnormal cooling channel gas side wall temperature T wg_AOC Higher than the temperature limit T of the material of the thrust chamber wg_limit , then the rated operating conditions of the hot start test are replaced and step S4 is repeated to carry out abnormal cooling channel heat transfer calculation and evaluation until the rated operating conditions of the hot start test are safe; wherein, replacing the rated operating conditions of the hot start test mainly involves adjusting the thrust chamber inlet rated conditions to reduce the parameter settings therein so that the heat generated by the entire thrust chamber can be reduced.

[0186] In this embodiment, the temperature resistance limit of the material of the thrust chamber is T wg_limit It is related to the material properties and can be obtained by taking a certain margin downward from the material's limit temperature. The set margin is determined according to the actual working conditions and will not be repeated here.

[0187] The above contents are merely examples of specific solutions of the present invention. For devices and structures not described in detail, it should be understood that they can be implemented by adopting general devices and methods available in the art.

[0188] The above description is merely one embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A 3D printing-based method for evaluating abnormal channel heat transfer in a regenerative cooling engine, characterized in that: A hot-run test is conducted on the rocket engine under preset safety conditions and a heat transfer evaluation is performed after the hot-run test is completed, which includes the following steps: S1. After completing the hot start test under safe working conditions, determine the overheating area of ​​the thrust chamber of the rocket engine, and identify the overheating temperature of the overheating area to obtain the overheating position node a Node overheat temperature T wg ( a ); S2. Based on the safe working conditions of the hot-start test, the heat transfer calculation of the normal cooling channel of the thrust chamber is carried out and the overheating position node is obtained. a Theoretical normal wall temperature on the gas side T wg_n ( a ); S3. Assumed overheating location node a The initial value of the first coolant flow rate of the abnormal cooling channel at m' , based on the initial value of the first coolant flow rate m' Carry out abnormal cooling channel heat transfer calculation to obtain the overheating location node a Theoretical node superheat temperature at T' wg ( a );Determine the theoretical node overheat temperature T' wg ( a ) and the node overheat temperature T wg ( a ) whether the preset conditions are met; if so, the first coolant flow initial value m' Final coolant flow as abnormal cooling channel m ; S4. Final coolant flow based on abnormal cooling channels m Obtain the coolant flow change ratio α between the abnormal cooling channel and the normal cooling channel, and the rated operating flow of the normal cooling channel under rated operating conditions. m RPL,n The rated operating flow of the abnormal cooling channel is obtained by adding the flow change ratio α m RPL , and based on the rated operating flow of the abnormal cooling channel m RPL Carry out abnormal cooling channel heat transfer calculation and evaluation, and output the rated abnormal cooling channel gas side wall temperature T wg_AOC ; If the rated abnormal cooling channel gas side wall temperature T wg_AOC Lower than the temperature limit T of the material of the thrust chamber wg_limit , then the rated operating conditions of the hot car test are safe and the test run can be carried out; If the rated abnormal cooling channel gas side wall temperature T wg_AOC Higher than the temperature limit T of the material of the thrust chamber wg_limit , then replace the rated operating conditions of the hot car test and repeat step S4 to carry out abnormal cooling channel heat transfer calculation and evaluation until the rated operating conditions of the hot car test are safe.

2. The method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to claim 1, characterized in that: In step S1, the overheating temperature of the overheating area is identified to obtain the overheating position node a Node overheat temperature T wg ( a ) step, a spectrophotometer is used to measure the color difference between the overheated area and the standard sample to determine the overheated position node a Node overheat temperature T wg ( a ).

3. The method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to claim 2, characterized in that: In step S2, based on the safety conditions of the hot start test, the heat transfer calculation of the normal cooling channel of the thrust chamber is carried out and the overheating position node is obtained. a Theoretical normal wall temperature on the gas side T wg_n ( a ) steps, including: S21. Input the safety operating condition parameters involved in the hot-run test safety operating conditions. These safety operating condition parameters include the thrust chamber safe operating condition inlet conditions and the normal cooling channel safe operating condition inlet conditions. The thrust chamber safe operating condition inlet conditions include the safe operating condition gas flow rate and the safe operating condition thrust chamber pressure. The normal cooling channel safe operating condition inlet conditions include the safe operating condition coolant inlet pressure, the safe operating condition coolant inlet temperature, and the safe operating condition normal cooling channel coolant flow rate. S22. Based on the safety operating condition parameters, perform thrust chamber regenerative cooling heat transfer calculations and output the overheating position node. a Theoretical normal wall temperature on the gas side T wg_n ( a ).

4. The method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to claim 3, characterized in that: In step S22, the step of performing thrust chamber regenerative cooling heat transfer calculation based on the safety operating condition parameters includes: S221. Obtain the structural parameters of the thrust chamber and divide the thrust chamber into multiple microelements along the axial direction; S222. Based on the thrust chamber safe operating condition inlet conditions and the preset combustion chamber temperature field calculation model, solve the safe operating condition gas parameters at any infinitesimal position; wherein, the safe operating condition gas parameters include: Mach number of the gas Ma , Gas side insulation wall temperature T aw and gas side convective heat transfer coefficient h gas ; The gas side convection heat transfer coefficient h gas It is obtained according to the semi-empirical Bartz formula and is expressed as: in, is the diameter of the thrust chamber throat, is the dynamic viscosity of the gas at the stagnation temperature, is the specific heat of gas at constant pressure, is the gas Prandtl number, is the thrust chamber pressure, is the thrust chamber characteristic velocity, is the qualitative temperature variation coefficient, is the throat curvature radius, , are the throat area and the cross-sectional area of ​​the segment respectively, is the thrust chamber temperature, is the gas specific heat ratio, is the Mach number of the gas, subscript is the hysteresis parameter, is the gas side wall temperature; S223. Assume that i The gas side wall temperature at the microelement , and solve the first i Heat flux density under safe working condition at a microelement , among which, i =1 microelement is at the normal cooling channel entrance position; The heat flux density under safe working condition Expressed as: ； S224. Obtain normal cooling channel parameters and the normal cooling channel entrance safety conditions, wherein the normal cooling channel parameters include: channel width, channel height, rib width, and number of channels at any microelement; S225. Based on the heat flux density of the safety working condition , carry out thermodynamic and hydraulic calculation of coolant in normal cooling channel, and obtain the i Coolant temperature under safe operating conditions at the infinitesimal point and safe operating condition coolant side wall temperature ; Wherein, the safe operating condition coolant temperature and the coolant side wall temperature under the safe operating condition Respectively expressed as: in, is the thickness of the inner wall of the thrust chamber, that is, the thickness of the wall between the coolant and the gas, is the thermal conductivity of the material, is the coolant side convective heat transfer coefficient, is the total efficiency of the rib surface; S226. Based on the safe working condition coolant side wall temperature , using the preset thrust chamber wall heat conduction model, solve the i Normal cooling channel gas side wall temperature at microelement ; Wherein, the normal cooling channel gas side wall temperature Expressed as: ； S227. Calculate the assumed gas side wall temperature and normal cooling channel gas side wall temperature If the relative error is less than or equal to the preset threshold, the i Heat flux density under safe working condition at infinitesimal point , gas side wall temperature , Normal cooling channel gas side wall temperature The coupled solution converges and the last calculated safety condition heat flux density is converted to 、 Gas side wall temperature , Normal cooling channel gas side wall temperature For the i The final parameter at the infinitesimal point; S228. Complete i After the calculation at the infinitesimal point, i Safe operating coolant temperature at +1 microelement and safe operating coolant pressure The calculation is as follows: in, 、 、 、 Respectively i The heat flux density of the safe working condition at each microelement, the heat exchange area on the gas side, the length of the cooling channel, the hydraulic diameter of the cooling channel, is the coolant flow rate of the normal channel under safe working conditions, is the specific heat capacity of the coolant, is the friction coefficient, For coolant dense flow, is the coolant density, For the i The coolant temperature of the safe working condition at the infinitesimal point is, For the i Coolant pressure in safe working condition at the microelement; Based on the iterative solution of steps S222 to S227, the heat flux density of the safe working condition along the normal cooling channel of the entire thrust chamber is obtained. , gas side wall temperature , Normal cooling channel gas side wall temperature , safe working condition coolant side wall temperature , safe operating coolant temperature and safe operating coolant pressure .

5. The method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to claim 4, characterized in that: In step S225, the coolant side convection heat transfer coefficient The heat transfer correlation is obtained by selecting a corresponding heat transfer correlation based on the coolant phase and the flow Reynolds number, wherein the coolant phase is one of gas, liquid, gas-liquid two-phase state, and supercritical state.

6. The method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to any one of claims 1 to 5, characterized in that: In step S3, it is assumed that the overheating position node a The initial value of the first coolant flow rate of the abnormal cooling channel at m' , based on the initial value of the first coolant flow rate m' Carry out abnormal cooling channel heat transfer calculation to obtain the overheating location node a Theoretical node superheat temperature at T' wg ( a ) step, the first coolant flow initial value m' Expressed as: m' = T wg_n ( a ) / T wg ( a )× m _n in, m _n is the coolant flow rate of the normal cooling channel.

7. The method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to claim 6, characterized in that: In step S3, the theoretical node overheat temperature is determined T' wg ( a ) and the node overheat temperature T wg ( a ) satisfies the preset conditions, if not, iteratively optimize the first coolant flow initial value m' The abnormal cooling channel heat transfer calculation is carried out again until the theoretical node overheating temperature T' wg ( a ) and the node overheat temperature T wg ( a ) satisfies the preset conditions, and the first coolant flow initial value after iterative optimization is m' Final coolant flow as abnormal cooling channel m ; Wherein, the initial value of the first coolant flow rate m' Based on theoretical node overheat temperature T' wg ( a ) and node overheat temperature T wg ( a ) is iteratively optimized and expressed as: ； The preset conditions are: ； in, ε is the preset threshold.

8. The method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to claim 7, characterized in that: In step S3, it is assumed that the overheating position node a The initial value of the first coolant flow rate of the abnormal cooling channel at m' , based on the initial value of the first coolant flow rate m' Carry out abnormal cooling channel heat transfer calculation to obtain the overheating location node a Theoretical node superheat temperature at T' wg ( a ) steps, including: S31. Obtaining structural parameters of the abnormal cooling channel and dividing the channel into multiple micro-elements along the abnormal cooling channel; S32. Solve the safe working condition gas parameters at any slot microelement based on the thrust chamber safe working condition inlet conditions and the preset combustion chamber temperature field calculation model; wherein, the safe working condition gas parameters include: the Mach number of the gas Ma , Gas side insulation wall temperature T aw and gas side convective heat transfer coefficient h gas ; The gas side convection heat transfer coefficient h gas It is obtained according to the semi-empirical Bartz formula and is expressed as: in, is the diameter of the thrust chamber throat, is the dynamic viscosity of the gas at the stagnation temperature, is the specific heat of gas at constant pressure, is the gas Prandtl number, is the thrust chamber pressure, is the thrust chamber characteristic velocity, is the qualitative temperature variation coefficient, is the throat curvature radius, , are the throat area and the cross-sectional area of ​​the segment respectively, is the thrust chamber temperature, is the gas specific heat ratio, is the Mach number of the gas, subscript is the hysteresis parameter, is the gas side wall temperature; S33. Assume that j Abnormal cooling gas side wall temperature at each channel microelement , and solve the first j Abnormal cooling channel heat flux density at each channel element , among which, j = 1 channel element is at the abnormal cooling channel entrance position; Then, the abnormal cooling channel heat flux density Expressed as: ； S34. Obtain abnormal cooling channel parameters and abnormal cooling channel inlet conditions, wherein the abnormal cooling channel parameters include: channel width, channel height, rib width, and number of channels at any channel microelement; the abnormal cooling channel inlet conditions include: coolant inlet pressure, coolant inlet temperature, and initial value of the first coolant flow rate. m' ; S35. Based on abnormal cooling channel heat flux , carried out thermal and hydraulic calculation of coolant in abnormal cooling channel, and obtained the j Abnormal cooling channel coolant temperature at each channel element and abnormal cooling channel coolant side wall temperature ; Wherein, the abnormal cooling channel coolant temperature and the abnormal cooling channel coolant side wall temperature Respectively expressed as: in, is the thickness of the inner wall of the thrust chamber, that is, the thickness of the wall between the coolant and the gas, is the thermal conductivity of the material, is the coolant side convective heat transfer coefficient, is the total efficiency of the rib surface; S36. Based on the abnormal cooling channel coolant side wall temperature , using the preset thrust chamber wall heat conduction model, solve the j Abnormal cooling channel gas side wall temperature at each channel microelement ; Wherein, the abnormal cooling channel gas side wall temperature Expressed as: ； S37. Calculate the assumed abnormal cooling gas side wall temperature and abnormal cooling channel gas side wall temperature If the relative error is less than or equal to the preset threshold, the j Abnormal cooling channel heat flux density at each channel element , Abnormal cooling gas side wall temperature , Abnormal cooling channel gas side wall temperature The coupled solution converges and the abnormal cooling channel heat flux calculated last time is converted to 、 Abnormal cooling channel gas side wall temperature For the j The final parameters at each infinitesimal channel; S38. Complete j After calculating the position of each slot element, j The parameters at the infinitesimal element of the channel are used as the j +1 channel microelement entrance conditions, and based on the iterative solution according to steps S32 to S37, obtain the abnormal cooling channel heat flux density along the entire abnormal cooling channel under safe working conditions , Abnormal cooling channel gas side wall temperature , Abnormal cooling channel coolant side wall temperature , Abnormal cooling channel coolant temperature and abnormal cooling channel coolant pressure .

9. The method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to claim 8, characterized in that: In step S4, the final coolant flow rate of the abnormal cooling channel is m In the step of obtaining a coolant flow change ratio α between the abnormal cooling channel and the normal cooling channel, the coolant flow change ratio α is expressed as: α= m / m _n in, m _n is the coolant flow rate of the normal cooling channel; In step S4, based on the rated working condition flow rate of the normal cooling channel under rated working conditions m RPL,n The rated operating flow of the abnormal cooling channel is obtained by adding the flow change ratio α m RPL In the step of m RPL Expressed as: m RPL= α× m RPL,n 。 10. The method for evaluating abnormal channel heat transfer in a regenerative cooling engine based on 3D printing according to claim 9, characterized in that: In step S4, based on the rated operating flow of the abnormal cooling channel m RPL The steps for conducting abnormal cooling channel heat transfer calculation evaluation include: S41. Obtaining structural parameters of the abnormal cooling channel and dividing the abnormal cooling channel into multiple channel microelements; S42. Based on the preset thrust chamber rated operating condition inlet conditions and the preset combustion chamber temperature field calculation model, the rated operating condition gas parameters at any slot microelement are solved; wherein, the thrust chamber rated operating condition inlet conditions include: rated operating condition gas flow rate and rated operating condition thrust chamber pressure, and the rated operating condition gas parameters include: Mach number of the gas Ma , Gas side insulation wall temperature T aw and gas side convective heat transfer coefficient h gas ; The gas side convection heat transfer coefficient h gas It is obtained according to the semi-empirical Bartz formula and is expressed as: in, is the diameter of the thrust chamber throat, is the dynamic viscosity of the gas at the stagnation temperature, is the specific heat of gas at constant pressure, is the gas Prandtl number, is the thrust chamber pressure, is the thrust chamber characteristic velocity, is the qualitative temperature variation coefficient, is the throat curvature radius, , are the throat area and the cross-sectional area of ​​the segment respectively, is the thrust chamber temperature, is the gas specific heat ratio, is the Mach number of the gas, subscript is the hysteresis parameter, is the gas side wall temperature; S43. Assume that k Rated abnormal cooling gas side wall temperature at each channel microelement , and solve the first k Rated operating channel heat flux density at each channel element , among which, k = 1 channel element is at the abnormal cooling channel entrance position; The rated operating channel heat flux density Expressed as: ； S44. Obtain abnormal cooling channel parameters and abnormal cooling channel rated working condition inlet conditions, wherein the abnormal cooling channel parameters include: channel width, channel height, rib width, and number of channels at any channel microelement; the abnormal cooling channel rated working condition inlet conditions include: rated working condition coolant inlet pressure, rated working condition coolant inlet temperature, and rated working condition flow rate of the abnormal cooling channel. m RPL ; S45. Based on rated operating conditions slot heat flux , carried out thermal and hydraulic calculation of coolant in abnormal cooling channel, and obtained the k Rated operating coolant temperature at each channel element and rated operating coolant side wall temperature ; Wherein, the rated operating coolant temperature and the rated operating coolant side wall temperature Respectively expressed as: in, is the thickness of the inner wall of the thrust chamber, that is, the thickness of the wall between the coolant and the gas, is the thermal conductivity of the material, is the coolant side convective heat transfer coefficient, is the total efficiency of the rib surface; S46. Based on the rated operating condition coolant side wall temperature , using the preset thrust chamber wall heat conduction model, solve the k The abnormal cooling channel gas side wall temperature at the rated working condition at each channel microelement ; Among them, the rated working condition abnormal cooling channel gas side wall temperature Expressed as: ； S47. Calculate the assumed rated abnormal cooling gas side wall temperature and rated working condition abnormal cooling channel gas side wall temperature If the relative error is less than or equal to the preset threshold, the k The heat flux density of the slot at the rated working condition at each slot element , Rated abnormal cooling gas side wall temperature , Abnormal cooling channel gas side wall temperature under rated working conditions The coupled solution converges and the last calculated rated working condition channel heat flux density is converted to 、 Abnormal cooling channel gas side wall temperature under rated operating conditions For the k The final parameters at each infinitesimal channel; S48. Complete k After calculating the position of each slot element, k The parameters at the infinitesimal element of the channel are used as the k +1 channel microelement entrance conditions, and based on the iterative solution according to steps S42 to S47, obtain the rated working condition channel heat flux density along the entire abnormal cooling channel , Abnormal cooling channel gas side wall temperature under rated working conditions , rated operating condition coolant side wall temperature , Rated operating coolant temperature and rated operating coolant pressure .

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