A combined thermal protection / thermal management coupling calculation method for a power nozzle

Abstract

The application discloses a combined power nozzle thermal protection / thermal management coupling calculation method, and belongs to the field of aircraft nozzle design.The steps of the method are as follows: a nozzle solid geometric model, an internal flow channel geometric model and a cabin geometric model are established;the established nozzle solid geometric model and the internal flow channel geometric model are subjected to grid division and parameter setting, and the pretreatment of a simulation model is realized;coupling analysis initialization is carried out;fluid-solid thermal coupling analysis is carried out;result post-processing is carried out;and cabin cooling simulation is carried out.The application establishes a fluid calculation domain and a solid calculation domain for the combined power nozzle geometric model, sets a coupling interface between the calculation domains for thermal flow and temperature coupling iteration, realizes accurate calculation of thermal protection / thermal management coupling under nozzle active cooling based on the above setting, and improves temperature prediction accuracy.The application carries out numerical simulation analysis on active cooling of the nozzle under a severe thermal environment of the nozzle, reveals the nozzle heat transfer and cooling design mechanism, and thus provides a theoretical basis for thermal protection / thermal management design.

Description

Technical Field

[0001] This invention belongs to the field of aircraft nozzle design and proposes a coupled calculation method for thermal protection / thermal management of combined power nozzles to solve the coupling problem in the design and analysis of thermal protection / thermal management of nozzles under high temperature and high pressure gas flow. Background Technology

[0002] The combined propulsion nozzle of an aircraft is an important component of the propulsion system. It expands, accelerates, and exhausts the high-temperature airflow from the engine combustion chamber to generate effective thrust. However, the harsh force and thermal environment within the flow channel poses significant challenges to the structural design of the combined propulsion nozzle. There is an urgent need to explore integrated structural / functional technologies that integrate aerodynamic performance, load-bearing capacity, thermal protection, and thermal management. Furthermore, it is essential to develop coupled design methods and processes for thermal protection and thermal management to form a nozzle design framework and scheme.

[0003] Combined propulsion nozzles involve complex interactions between aerodynamic heating of the internal flow channel gas, active cooling, and heat transfer to the load-bearing structure, representing a typical multidisciplinary coupled problem. Currently, there is no effective simulation calculation method for thermal protection / thermal management of combined propulsion nozzles. It is necessary to study a coupled analysis method that can comprehensively consider aerodynamic performance, active cooling, and structural heat transfer to provide a basis for the thermal protection / thermal management design of nozzles. Summary of the Invention

[0004] To address the aforementioned problems and difficulties, the technical problem to be solved by the combined power nozzle thermal protection / thermal management coupled calculation method disclosed in this invention is: to accurately simulate the aerodynamic characteristics, active cooling performance and structural temperature of the combined power nozzle through coupled analysis, to reveal the aerodynamic performance, cooling and temperature conditions of the nozzle, to provide a theoretical basis for the design of nozzle thermal protection / thermal management, and to solve practical engineering application problems of the nozzle.

[0005] This invention is achieved through the following technical solution:

[0006] A combined thermal protection / thermal management coupling calculation method for a combined power nozzle, comprising the following steps:

[0007] Step 1: Establish the solid geometry model of the nozzle, the internal flow channel geometry model, and the compartment geometry model.

[0008] Taking the combined power nozzle as the research object, geometric modeling software was used for geometric modeling. The internal flow channel geometric model includes the nozzle gas flow channel, the gas film cooling flow channel, and the external flow field. The nozzle solid geometric model includes the heat shield, the nozzle wall, the load-bearing frame, and the rear outer skin.

[0009] The modeling software used is the geometry construction function of CATIA software.

[0010] Step 2 involves meshing and parameter setting of the nozzle solid geometry model and internal flow channel geometry model established in Step 1 to achieve preprocessing of the simulation model.

[0011] Step 2.1: Preprocess the internal flow channel geometry model.

[0012] First, load the internal flow channel geometry model file, then name each surface of the internal flow channel geometry model, defining the inner side of the nozzle wall and the outer surface of the heat shield as the coupling interaction surface. Set the mesh size and the number of boundary layer meshes, and then generate the fluid mesh. Set the inlet total temperature, total pressure, outlet boundary conditions, and initial temperature parameters of the coupling interaction surface. The fluid mesh generation software is Star-ccm+.

[0013] Step 2.2: Preprocess the solid geometry model of the nozzle.

[0014] Import the solid geometry model of the nozzle and mesh it. The nozzle wall, load-bearing frame, and rear outer skin are shell elements, while the heat shield is a solid element. Set the initial structural temperature, load-bearing frame thickness, and nozzle wall thickness parameters. Define the inner side of the nozzle wall and the inner and outer surfaces of the heat shield as surface assemblies. Generate and modify the calculation input file, setting the inner side of the nozzle wall and the inner and outer surfaces of the heat shield as coupling surfaces, and setting temperature and heat flux as interactive parameters. ABAQUS was used to mesh the solid geometry model of the nozzle.

[0015] Step 3: Perform coupling analysis initialization.

[0016] Star-ccm+ first performs calculations based on the initial conditions set in step 2 to obtain the Mach number, heat flux distribution, and pressure distribution of the nozzle under the initial isothermal wall.

[0017] Step 4: Conduct fluid-structure-thermal coupling analysis.

[0018] Using the co-simulation platform provided by Star-ccm+ software, the coupled solid domain is linked to an ABAQUS model. The coupling interaction surface is set as the external program coupling specification, and the path information of the solid calculation input file is set. The interaction time interval and interaction parameters are set for the coupling interface. The coupled simulation is started through the co-simulation mechanism. When coupling begins, Star-ccm+ transmits the heat flow data of the inner side of the nozzle wall and the inner and outer surfaces of the heat shield to ABAQUS. ABAQUS obtains the nozzle temperature distribution data through heat transfer calculation and transmits it back to Star-ccm+. Through multiple bidirectional data transmissions, the coupled iteration of heat flow and temperature is achieved.

[0019] When the residual curve reaches a steady state and the nozzle wall temperature also reaches a steady state, the calculation results are considered to have converged.

[0020] The fluid-structure-thermal coupling analysis described in step 4 is implemented using Star-ccm+ and ABAQUS.

[0021] Step 5: Perform post-processing of the results.

[0022] Using the simulation results obtained from steps 1 to 4, Star-ccm+ outputs Mach number and heat flux cloud map results files, and ABAQUS outputs temperature distribution results files. Typical results are extracted, including heat shield temperature, nozzle wall temperature, Mach number distribution, heat flux distribution cloud map, and temperature variation curves over time at typical locations.

[0023] The optimized design of the structural temperature is achieved by changing the cooling gas flow rate and the distribution of the film cooling pores.

[0024] Step 6: Chamber cooling simulation.

[0025] Import the cabin geometry model and generate a fluid mesh. For a given structural wall temperature, introduce coolant into the cabin, calculate the internal temperature distribution and the surface temperature distribution of the equipment, and evaluate the cooling effect of the coolant on the equipment.

[0026] The fluid mesh generation software and simulation calculation software mentioned in step 6 are Fluent.

[0027] The beneficial effects of this invention are:

[0028] 1. This invention discloses a coupled calculation method for thermal protection / thermal management of a combined propulsion nozzle. A fluid calculation domain and a solid calculation domain are established for the geometric model of the combined propulsion nozzle. A coupling interface is set between the calculation domains to perform coupled iteration of heat flow and temperature. Based on the above settings, accurate calculation of thermal protection / thermal management under active cooling of the nozzle is achieved, thereby improving the accuracy of temperature prediction.

[0029] 2. This invention discloses a coupled calculation method for thermal protection / thermal management of a combined power nozzle, which performs numerical simulation analysis on active cooling of the nozzle under harsh thermal conditions to reveal the heat transfer and cooling design mechanism of the nozzle, thereby providing a theoretical basis for thermal protection / thermal management design. Attached Figure Description

[0030] Figure 1 Flowchart of the analytical method of this invention;

[0031] Figure 2 Solid model in the embodiments of the present invention;

[0032] Figure 3 The internal flow channel fluid model in this embodiment of the invention;

[0033] Figure 4 The embodiment of this invention uses a cabin fluid model;

[0034] Figure 5 Mach number cloud map of the internal flow channel in this embodiment of the invention;

[0035] Figure 6 Thermal flux cloud diagram of the nozzle wall in this embodiment of the invention;

[0036] Figure 7 Temperature contour map of nozzle wall surface in an embodiment of the present invention;

[0037] Figure 8 Temperature cloud map of the symmetry plane of the compartment in this embodiment of the invention. Detailed Implementation

[0038] To better illustrate the combined power nozzle thermal protection / thermal management coupling calculation method of the present invention, test calculations were performed using the method of the present invention in conjunction with the accompanying drawings and embodiments, making the technical solution and beneficial effects clearer.

[0039] Example 1

[0040] Figure 1 The analysis process of the combined power nozzle thermal protection / thermal management coupled calculation method disclosed in this embodiment is as follows:

[0041] Step 1: Establish a solid geometric model of the nozzle using geometric software. Figure 2 ), Internal flow channel geometric model ( Figure 3 ), cabin geometry model ( Figure 4 The internal flow channel geometry model includes the nozzle gas flow channel, film cooling flow channel, and external flow field, while the nozzle solid geometry model includes the heat shield, nozzle wall, load-bearing frame, and rear external skin.

[0042] The modeling software used is the geometry construction function of CATIA software.

[0043] Step 2 involves meshing and parameter setting of the nozzle solid geometry model and internal flow channel geometry model established in Step 1 to achieve preprocessing of the simulation model.

[0044] Step 2.1: Preprocess the internal flow channel geometry model.

[0045] First, load the internal flow channel geometry model file. Then, name each surface of the internal flow channel geometry model, such as the gas inlet, cooling gas inlet, pressure outlet, nozzle wall, and heat shield wall. Define the inner side of the nozzle wall and the outer surface of the heat shield as the coupling interaction surface. Set the mesh size, boundary layer mesh quantity, etc., and generate the fluid mesh. Set the boundary layer mesh quantity to 20 layers. Set parameters such as the total temperature and total pressure of the incoming flow inlet, and set the nozzle outlet as a pressure outlet. Specifically, the total temperature of the gas flow at the nozzle inlet is set to 2000K, the total temperature of the cooling gas is set to 700K, the fluid is an ideal gas, and the turbulence model is the k-ε model. The coupling interaction surface is set as an isothermal wall with a wall temperature of 300K.

[0046] Step 2.2: Preprocess the solid geometry model of the nozzle.

[0047] Import the solid geometry model of the nozzle, set the simulation analysis to heat conduction analysis, and mesh the solid geometry model of the nozzle. The nozzle wall, load-bearing frame, and rear outer skin are rendered using DS4 shell elements, while the heat shield is rendered using DC3D4 solid elements. Shell and solid elements are connected using bonded constraints. The thickness of the load-bearing frame elements is set to 2mm, the nozzle wall element thickness to 2mm, and the skin element thickness to 1.5mm. The initial structural temperature is set to 300K. The inner side of the nozzle wall and the inner and outer surfaces of the heat shield are defined as a set of coupling surfaces. The calculation input file is generated and modified, and coupling setting parameters are entered, including the defined set of coupling surfaces, interactive heat flux, and temperature information.

[0048] Step 3: Perform coupling analysis initialization.

[0049] Star-ccm+ first performs calculations based on the initial environment set above to obtain data such as aerodynamic pressure and heat flux distribution under the isothermal wall of the nozzle.

[0050] Step 4: Conduct fluid-structure-thermal coupling analysis.

[0051] A fluid-structure-thermal coupling simulation of a combined-power nozzle was performed using the co-simulation platform provided by Star-ccm+ software. In Star-ccm+, the coupled solid domain computational model was set as an ABAQUS external continuum, the coupling interaction surface was set as the external program coupling specification, and the solid calculation input file path was configured. The inner side of the nozzle wall and the inner and outer surfaces of the heat shield were set as coupling interfaces, the coupling time interval was set to 1 second, and the interaction parameters were temperature and heat flux. The total simulation time was 100 seconds. At the start of coupling, Star-ccm+ transmitted the transiently calculated heat flux data of the inner side of the nozzle wall and the inner and outer surfaces of the heat shield to ABAQUS. ABAQUS obtained the nozzle temperature distribution data through transient heat transfer calculations and transmitted it back to Star-ccm+. Through bidirectional data transmission, coupled iterative temperature simulation was achieved.

[0052] When the residual curve reaches a steady state and the temperature also reaches a steady state, the calculation results are considered to have converged.

[0053] The coupled simulation analysis described in step 4 is implemented by calling ABAQUS using Star-ccm+.

[0054] Step 5: Perform post-processing of the results.

[0055] The calculation results are obtained using the coupling analysis method described in steps 1 to 4, and the Star-ccm+ outputs result files such as Mach number contour plots and heat flow contour plots, as shown below. Figure 5 , 6 As shown, the temperature distribution output by ABAQUS is as follows: Figure 7 As shown. Typical results can also be extracted, including cloud maps of heat shield temperature and Mach number distribution, and temperature change curves over time at typical locations.

[0056] Furthermore, by changing the cooling gas flow rate and the distribution of the film cooling pores, the structural temperature can be optimized.

[0057] Step 6: Chamber cooling simulation.

[0058] Import the cabin geometry model into Fluent and generate a fluid mesh. Given the structural wall temperatures, introduce coolant into the cabin, calculate the internal temperature distribution and the surface temperature distribution of the equipment, and evaluate the cooling effect of the coolant on the internal equipment. The cabin temperature contour map is shown below. Figure 8 As shown.

[0059] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combined power nozzle thermal protection / thermal management coupling calculation method, characterized in that, The steps are as follows: Step 1: Establish the solid geometry model of the nozzle, the internal flow channel geometry model, and the compartment geometry model; Taking the combined power nozzle as the research object, geometric modeling software was used for geometric modeling. The internal flow channel geometric model includes the nozzle gas flow channel, the gas film cooling flow channel, and the external flow field. The nozzle solid geometric model includes the heat shield, the nozzle wall, the load-bearing frame, and the rear outer skin. The modeling software used is the geometry construction function of CATIA software; Step 2: Mesh and parameter settings are performed on the nozzle solid geometry model and internal flow channel geometry model established in Step 1 to achieve preprocessing of the simulation model; Step 2.1: Preprocess the internal flow channel geometric model; First, load the internal flow channel geometric model file, then name each surface of the internal flow channel geometric model, defining the inner side of the nozzle wall and the outer surface of the heat shield as the coupling interaction surface; set the mesh size and the number of boundary layer meshes and generate the fluid mesh; set the total inlet temperature, total pressure, outlet boundary conditions, and initial temperature parameters of the coupling interaction surface; use Star-ccm+ software to generate the fluid mesh. Step 2.2: Preprocess the solid geometry model of the nozzle; Import the solid geometry model of the nozzle and mesh it, where the nozzle wall, load-bearing frame, and rear outer skin are shell elements, and the heat shield is a solid element. Set the initial structural temperature, load-bearing frame thickness, and nozzle wall thickness parameters, and define the inner side of the nozzle wall and the inner and outer surfaces of the heat shield as surface sets. Generate and modify the calculation input file, setting the inner side of the nozzle wall and the inner and outer surfaces of the heat shield as coupling surfaces, and setting temperature and heat flux as interaction parameters. The software used for meshing the solid geometry model of the nozzle is ABAQUS. Step 3: Perform coupling analysis initialization; Star-ccm+ first calculates the Mach number, heat flux distribution, and pressure distribution of the nozzle under the initial isothermal wall using the initial conditions set in step 2. Step 4: Conduct fluid-structure-thermal coupling analysis; Using the co-simulation platform provided by Star-ccm+ software, the coupled solid domain is linked to the ABAQUS model. The coupling interaction surface is set as the external program coupling specification, and the path information of the solid calculation input file is set. The interaction time interval and interaction parameters are set for the coupling interface. The coupled simulation is started through the co-simulation mechanism. When coupling starts, Star-ccm+ transmits the heat flow data of the inner side of the nozzle wall and the inner and outer surfaces of the heat shield to ABAQUS. ABAQUS obtains the nozzle temperature distribution data through heat transfer calculation and transmits it back to Star-ccm+. After multiple bidirectional data transmissions, the coupling iteration of heat flow and temperature is realized. When the residual curve reaches a steady state, and the nozzle wall temperature also reaches a steady state, the calculation results are considered to have converged. The fluid-structure-thermal coupling analysis described in step 4 is implemented using Star-ccm+ and ABAQUS. Step 5: Perform post-processing of the results; Using the simulation results obtained from steps 1 to 4, Star-ccm+ outputs Mach number cloud map and heat flux cloud map result files, and ABAQUS outputs temperature distribution result files; typical results are extracted, including heat shield temperature, nozzle wall temperature, Mach number distribution, heat flux distribution cloud map, and temperature change curves at typical locations over time. The optimized design of the structural temperature is achieved by changing the cooling gas flow rate and the distribution of the film cooling pores. Step 6, cabin cooling simulation; Import the cabin geometry model and generate a fluid mesh; for a given structural wall temperature, introduce coolant into the cabin, calculate the temperature distribution inside the cabin and the surface temperature distribution of the equipment inside the cabin, and evaluate the cooling effect of the coolant on the equipment inside the cabin. The fluid mesh generation software and simulation calculation software mentioned in step 6 are Fluent.

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