Method and system for designing a flow-thermal coupled compressor

Abstract

The present application relates to a kind of flow heat coupling compressor design method and system, comprising: based on the construction of three-dimensional conjugate flow heat coupling model of compressor;Based on the construction of one-dimensional non-adiabatic pipeline dynamics model of compressor peripheral pipeline;At the interface of three-dimensional conjugate flow heat coupling model and one-dimensional non-adiabatic pipeline dynamics model, double coupling interface is constructed;Based on double coupling interface, one-dimensional-three-dimensional time-space synchronous flow heat coupling iterative calculation is carried out, and the transient flow field distribution and temperature field distribution of compressor system are solved simultaneously;Based on the transient flow field distribution and temperature field distribution, set initial thermal boundary condition of heat accumulation, extract the internal flow field instability evolution characteristics and critical surge boundary data of compressor, and the structure optimization design of compressor is carried out.The present application can improve the accuracy of hot surge boundary prediction, effectively widen the stable working range of compressor, improve the reliability and environmental adaptability of whole machine.

Description

Technical Field

[0001] This invention belongs to the field of fluid machinery aerodynamic simulation and aerodynamic design technology, specifically relating to a fluid-thermal coupling compressor design method and system. Background Technology

[0002] Turbocharging technology is a core technology for improving the power density of power machinery and reducing emissions. As a key power-bearing component of the turbocharger, the compressor's stable operating range (i.e., surge margin) directly affects the low-speed dynamic response and operational safety of the entire system. In practical engineering applications, turbochargers are often located in extreme high-temperature thermal environments. The exhaust heat from the coaxial high-temperature turbine is conducted to the compressor side through the intermediate bearing housing, and combined with the ambient heat radiation from the engine compartment, it creates a "heat immersion" effect. The internal airflow of the compressor decreases in density and increases in viscosity after heating, which significantly alters the flow field structure, causing distortion of the compressor characteristic curve, and drifting the surge boundary towards the high-flow-rate region, severely weakening aerodynamic stability.

[0003] Existing compressor surge prediction and aerodynamic design methods mainly suffer from the following technical shortcomings: First, traditional one-dimensional system simulations heavily rely on compressor characteristic diagrams obtained from cold bench tests. (Map) cannot dynamically reflect the unsteady effects of heat transfer on boundary conditions, nor can it capture the details of three-dimensional flow distortion inside the compressor.

[0004] Second, although pure three-dimensional unsteady conjugate heat transfer simulation can realize fluid-structure conjugate heat transfer calculation, it is difficult to include large-volume, aspect ratio peripheral pipes into the full three-dimensional calculation domain due to computational resource limitations. It often uses simplified boundaries such as constant back pressure, loses the acoustic response characteristics of the pipe system, and has insufficient accuracy in system-level surge prediction.

[0005] Third, existing one-dimensional-three-dimensional coupled simulations are mostly based on adiabatic assumptions, only achieving aerodynamic parameter coupling, without constructing a synchronous transmission channel for thermodynamic parameters, ignoring the influence of thermal inertia in the three-dimensional solid domain, unsteady heat transfer in pipelines, and thermal immersion effects on the flow field, making it impossible to carry out dynamic simulation of thermal-surge under real thermal conditions, and the prediction of surge boundary and flow field instability characteristics under high-temperature conditions is seriously distorted.

[0006] Therefore, there is an urgent need in this field for a compressor design method that can simultaneously realize one-dimensional and three-dimensional fluid-thermal coupling calculations, take into account the acoustic boundary of the pipeline and three-dimensional unsteady conjugate heat transfer, and complete thermal-surge dynamic simulation, so as to achieve accurate expansion and stability design of compressors under harsh thermal environments. Summary of the Invention

[0007] In view of the above-mentioned defects or deficiencies in the prior art, the present invention proposes a flow-thermal coupling compressor design method and system.

[0008] Firstly, a fluid-thermal coupled compressor design method is provided, comprising: constructing a three-dimensional conjugate fluid-thermal coupled model based on the compressor, wherein the three-dimensional conjugate fluid-thermal coupled model includes a three-dimensional fluid domain and a three-dimensional solid domain, and a conjugate heat transfer interface is provided between the three-dimensional fluid domain and the three-dimensional solid domain; constructing a one-dimensional non-adiabatic pipeline dynamic model based on the compressor's peripheral pipeline, wherein the one-dimensional non-adiabatic pipeline dynamic model integrates mass conservation equations, momentum conservation equations, and energy conservation equations with unsteady heat transfer source terms; and constructing a dual coupling interface at the interface between the three-dimensional conjugate fluid-thermal coupled model and the one-dimensional non-adiabatic pipeline dynamic model, wherein the dual coupling interface has an aerodynamic parameter transmission channel for transmitting wave system information and a thermodynamic parameter transmission channel for transmitting energy information. The system employs a channel; based on the dual coupling interface, it performs one-dimensional to three-dimensional spatiotemporal synchronous flow-thermal coupling iterative calculations, synchronously exchanging wave system information and energy information in each time step to achieve pressure wave non-reflection transmission, and synchronously solving for the transient flow field distribution and temperature field distribution of the compressor system; based on the transient flow field distribution and the temperature field distribution, it sets initial thermal boundary conditions for heat accumulation, and performs dynamic simulation of thermal-surge under varying operating conditions by dynamically adjusting the flow area of ​​the throttle valve at the end of the one-dimensional non-insulated pipeline, extracting the internal flow field instability evolution characteristics and critical surge boundary data of the compressor; based on the critical surge boundary data and the internal flow field instability evolution characteristics, it identifies the heat accumulation region, and performs aerodynamic profile optimization design or thermal management structure optimization design of the compressor.

[0009] In one alternative embodiment, the three-dimensional fluid domain includes an inlet, an impeller channel, a diffuser, and a volute cavity; and / or the three-dimensional solid domain includes an aluminum alloy impeller body, a back disk, and a volute outer shell body.

[0010] In one optional implementation, the unsteady heat source term is used to solve for the real-time transient heat transfer between the airflow inside the pipe and the pipe wall; the real-time transient heat transfer is calculated based on the set physical parameters of the pipe wall material, the pipe wall thickness parameters, and the dynamic convection heat transfer coefficient, and the dynamic convection heat transfer coefficient is updated in real time according to the Reynolds number of the transient airflow inside the pipe.

[0011] In one optional implementation, constructing the aerodynamic parameter transmission channel specifically includes: transferring right-moving Riemann invariants from a one-dimensional non-adiabatic pipeline dynamics model to a three-dimensional conjugate flow-thermal coupling model, thereby updating the inlet pressure and airflow velocity of the three-dimensional conjugate flow-thermal coupling model; and feeding back left-moving Riemann invariants from the three-dimensional conjugate flow-thermal coupling model to the one-dimensional non-adiabatic pipeline dynamics model to achieve continuous pressure wave transmission without reflection.

[0012] In one optional implementation, constructing the thermal parameter transfer channel specifically includes: the one-dimensional non-adiabatic pipeline dynamics model outputting the total temperature of the interface nodes to the three-dimensional conjugate flow thermal coupling model as the three-dimensional inlet thermal boundary; the three-dimensional conjugate flow thermal coupling model feeding back the surface-weighted average total temperature and real-time mass flow rate of the interface to the one-dimensional non-adiabatic pipeline dynamics model for iteratively updating the energy state parameters of the one-dimensional non-adiabatic pipeline dynamics model system.

[0013] In one optional implementation, the three-dimensional fluid domain and the one-dimensional non-adiabatic pipeline dynamic model use a microsecond-level calculation time step, while the three-dimensional solid domain uses a millisecond-level calculation time step; the three-dimensional fluid domain and the three-dimensional solid domain exchange heat flux data and temperature field distribution data according to a preset thermal coupling synchronization period.

[0014] In one alternative implementation, the structural optimization design of the compressor specifically includes at least one of aerodynamic profile optimization and thermal management structure optimization.

[0015] In one optional implementation, the aerodynamic profile of the compressor impeller tip is modified according to the evolution law of airflow separation induced by high temperature, thereby completing the optimization of the compressor aerodynamic profile.

[0016] In one optional implementation, taking into account the temperature gradient distribution characteristics of the three-dimensional solid domain, an air insulation cavity or fluid cooling channel is added to the inner side of the compressor back plate or the back of the diffuser channel to block heat conduction and diffusion to the main intake area, thereby completing the optimization of the compressor thermal management structure.

[0017] Secondly, the present invention also proposes a compressor design system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement any of the flow-thermal coupling compressor design methods described in the present invention.

[0018] The beneficial effects of this invention are as follows: By using dual coupling simulation of three-dimensional conjugate flow thermal coupling and one-dimensional non-adiabatic pipeline model, both computational accuracy and efficiency are taken into account, the impact of unsteady thermal effects such as thermal immersion and thermal accumulation on the aerodynamic characteristics of the compressor is realistically reproduced, and the accuracy of thermal surge boundary prediction is improved; and based on the thermally induced instability mechanism, the aerodynamic optimization and thermal management structure are designed in a coordinated manner, which fundamentally improves the flow stability in the thermal environment, effectively broadens the stable operating range of the compressor, and improves the overall reliability and environmental adaptability. Attached Figure Description

[0019] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0020] Figure 1A flowchart of a flow-thermal coupling compressor design method provided in an embodiment of the present invention;

[0021] Figure 2 A flowchart of a flow-thermal coupling compressor design method provided in another embodiment of the present invention. Detailed Implementation

[0022] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] Please refer to Figure 1 and Figure 2 The present invention provides a flow-thermal coupled compressor design method, which includes the following steps:

[0024] Step S101: Construct a three-dimensional conjugate flow-thermal coupling model based on the compressor. The three-dimensional conjugate flow-thermal coupling model includes a three-dimensional fluid domain and a three-dimensional solid domain. A conjugate heat transfer interface is provided between the three-dimensional fluid domain and the three-dimensional solid domain.

[0025] Step S103: Construct a one-dimensional non-adiabatic pipeline dynamic model based on the compressor peripheral pipeline. The one-dimensional non-adiabatic pipeline dynamic model integrates the mass conservation equation, the momentum conservation equation, and the energy conservation equation with an unsteady heat transfer source term.

[0026] Step S105: At the interface between the three-dimensional conjugate flow thermal coupling model and the one-dimensional non-adiabatic pipeline dynamics model, a dual coupling interface is constructed. The dual coupling interface has an aerodynamic parameter transmission channel for transmitting wave system information and a thermodynamic parameter transmission channel for transmitting energy information.

[0027] Step S107: Perform one-dimensional-three-dimensional spatiotemporal synchronous flow-thermal coupling iterative calculation based on the dual coupling interface. In each time step, the wave system information and energy information are exchanged synchronously to realize the pressure wave non-reflection transmission and synchronously solve for the transient flow field distribution and temperature field distribution of the compressor system.

[0028] Step S109: Based on the transient flow field distribution and temperature field distribution, set the initial thermal boundary conditions for thermal accumulation. By dynamically adjusting the flow area of ​​the throttle valve at the end of the one-dimensional non-insulated pipeline, perform dynamic simulation of thermal surge under varying operating conditions, and extract the internal flow field instability evolution characteristics and critical surge boundary data of the compressor.

[0029] Step S1011: Based on the critical surge boundary data and the internal flow field instability evolution characteristics, the heat accumulation region is identified, and the compressor structure is optimized.

[0030] This invention first constructs a three-dimensional conjugate flow-thermal coupling model comprising a three-dimensional fluid domain and a three-dimensional solid domain, and a one-dimensional non-adiabatic pipeline dynamic model including wall heat transfer. By dynamically reducing the opening of the throttle valve at the end of the one-dimensional non-adiabatic pipeline dynamic model over time, the process of the compressor approaching and triggering flow field instability under thermal expansion can be simulated. Second, a dual "aerodynamic-thermal" coupling mechanism is established at the interface between the two, transmitting aerodynamic waves based on Riemann invariants and transmitting total temperature and mass flow rate based on energy conservation. Subsequently, in the coupled simulation, by dynamically adjusting the valve of the one-dimensional non-adiabatic pipeline dynamic model and superimposing a hot immersion environment, a thermal-surge dynamic simulation is performed to obtain the instability characteristics caused by thermal effects. In the variable-condition thermal-surge dynamic simulation, the fluid absorbs heat from the three-dimensional solid domain through the conjugate heat transfer interface, causing a decrease in fluid density. During the process of the throttle valve opening dynamically decreasing over time, the surge phenomenon induced prematurely by the shift of the compressor characteristic line to the high-flow-rate region due to gas thermal expansion is captured.

[0031] Finally, based on this, the compressor's aerodynamic profile or thermal insulation structure is synergistically optimized. This invention achieves high-fidelity multiphysics instability prediction, effectively improving the compressor's stability margin under complex thermal environments.

[0032] Among them, the construction of a three-dimensional conjugate fluid-thermal coupling model can accurately depict the unsteady heat transfer law between the fluid and solid structure inside the compressor, and truly restore the temperature distribution and heat conduction process of components such as impeller and volute, providing an accurate fluid-structure interaction basis for the analysis of flow instability under thermal effects.

[0033] A one-dimensional non-adiabatic pipeline dynamic model with unsteady heat transfer source terms is constructed. While ensuring computational efficiency, it can realistically reflect the transient heat exchange between the pipeline airflow and the pipe wall, breaking through the limitations of traditional adiabatic models and improving the thermodynamic realism of the pipeline system boundary.

[0034] A dual aerodynamic-thermal coupling interface is constructed to achieve synchronous transmission of pressure wave system and energy information between cross-scale models, ensuring continuous pressure, continuous temperature, and conserved flow at the interface, eliminating numerical reflection, and improving the stability of coupled simulation.

[0035] One-dimensional and three-dimensional spatiotemporal synchronous flow-thermal coupling iterative calculations can be carried out to simultaneously solve transient flow fields and temperature fields, taking into account the unsteady characteristics of aerodynamic fluctuations and heat transfer, and realizing high-fidelity dynamic simulation of the internal flow field of the compressor under high-temperature conditions.

[0036] Dynamic simulation of thermal surge under varying operating conditions can reproduce the entire process of surge occurrence and development under heat accumulation / hot immersion environments, accurately extract thermally induced flow instability characteristics and real surge boundaries, and solve the problem of distortion in high-temperature condition prediction by traditional methods.

[0037] Optimizing aerodynamic profiles and thermal management structures based on instability characteristics can accurately locate high-risk areas of heat accumulation and improve stability through synergistic expansion of stability from both aerodynamic suppression and thermal flow isolation aspects, thereby enhancing the compressor's stable operating margin in complex thermal environments.

[0038] This invention employs a dual-coupling simulation of three-dimensional conjugate flow thermal coupling and a one-dimensional non-adiabatic pipeline model, balancing computational accuracy and efficiency. It realistically reproduces the impact of unsteady thermal effects such as thermal immersion and thermal accumulation on the aerodynamic characteristics of the compressor, improving the accuracy of thermal surge boundary prediction. Furthermore, based on the thermally induced instability mechanism, it achieves the coordinated design of aerodynamic optimization and thermal management structure, fundamentally improving flow stability under thermal conditions, effectively broadening the stable operating range of the compressor, and enhancing the overall reliability and environmental adaptability of the machine.

[0039] Furthermore, the three-dimensional fluid domain includes the inlet, impeller flow channel, diffuser, and volute cavity; and / or the three-dimensional solid domain includes the aluminum alloy impeller body, back disk, and volute outer shell body.

[0040] The compressor's full-circumference geometric model is imported into computational fluid dynamics software and meshed. In this embodiment, the three-dimensional fluid domain includes the inlet, impeller flow channel, diffuser, and volute cavity, which can completely characterize the flow characteristics of the airflow from intake, work, diffusion to collection, and can realistically reproduce the entire flow evolution of the airflow inside the compressor, avoiding the loss of flow characteristics due to flow domain truncation. The lightweight alloy is preferably aluminum alloy. The three-dimensional solid domain includes the impeller solid, back disk, and volute outer shell solid made of aluminum alloy, which is used to characterize the solid heat transfer characteristics of the compressor's core load-bearing and heat exchange structure. It can accurately cover the key areas of heat accumulation and heat conduction inside the compressor, ensuring that the conjugate heat transfer calculation focuses on the core heat effect source, avoiding invalid calculations, and improving the simulation's relevance. A conserved heat flux conjugate heat transfer boundary is set at the interface between the three-dimensional fluid domain and the three-dimensional solid domain, which can ensure that the heat flux, temperature, and energy at the interface between the three-dimensional fluid domain and the three-dimensional solid domain are strictly conserved, eliminating numerical errors at the interface and achieving high-precision and high-stability unsteady conjugate heat transfer simulation. The fluid control equations are selected using SST, which has an energy equation solving module. Turbulence models are used to capture complex aerodynamic features such as near-wall flow separation, adverse pressure gradients, and strong shear flows with high accuracy.

[0041] Furthermore, the unsteady heat source term is used to solve for the real-time transient heat transfer between the airflow inside the pipe and the pipe wall; the real-time transient heat transfer is calculated based on the set physical parameters of the pipe wall material, the pipe wall thickness parameters, and the dynamic convection heat transfer coefficient, which is updated in real time according to the Reynolds number of the transient airflow inside the pipe.

[0042] In this embodiment, a structure including aspect ratio is established. A one-dimensional system model of the intake duct, pressure stabilizing tank, and variable cross-section outlet throttle valve is constructed. The non-adiabatic calculation module of the duct is activated, and the external environment is set to simulate the high-temperature state of an engine compartment. An unsteady heat transfer source term is introduced into the one-dimensional energy conservation equation. Using Newton's cooling formula and the transient Reynolds number, the convective heat transfer between the fluid inside the duct and the duct wall is calculated in real time. The unsteady heat transfer source term, as a core supplementary term to the one-dimensional energy conservation equation, is used to solve the dynamic transient heat transfer between the airflow inside the duct and the duct wall in real time. This real-time transient heat transfer is calculated in a coupled manner based on the pipe wall material properties, pipe wall thickness parameters, and the dynamic convective heat transfer coefficient. The dynamic convective heat transfer coefficient is iteratively updated according to the real-time change of the transient airflow Reynolds number inside the duct, thereby accurately characterizing the convective heat transfer intensity under different flow conditions.

[0043] By introducing the unsteady heat transfer source term into the one-dimensional energy conservation equation and combining it with the transient Reynolds number and Newton's cooling formula, the convective heat transfer between the airflow inside the pipe and the pipe wall is solved in real time through iteration, thus fully restoring the dynamic heat transfer process between the airflow inside the pipe and the external high-temperature environment.

[0044] By introducing unsteady heat source terms, the traditional one-dimensional adiabatic assumption can be broken, and the dynamic heat transfer of the pipe wall can be incorporated into the energy equation, which can realistically restore the heat transfer process in the high-temperature environment of the engine compartment and improve the realism of the thermodynamic simulation of the one-dimensional non-adiabatic pipe dynamic model.

[0045] Based on the real-time iterative convective heat transfer coefficient using transient Reynolds number, the heat transfer variation patterns under different flow velocities and flow states can be accurately captured, effectively improving the accuracy of transient heat transfer calculation.

[0046] Using a pipeline model with a length-to-diameter ratio of L / D=50, the actual intake and exhaust pipeline characteristics can be matched, and the acoustic response and heat accumulation effect of the pipeline can be fully reflected, ensuring that the one-dimensional system boundary is highly consistent with the actual compressor working environment.

[0047] By setting a high-temperature external environment and a fixed pipe wall thickness, the high-temperature operating conditions of the engine compartment can be accurately reproduced, providing realistic thermal boundary conditions for thermal-surge coupling simulation and avoiding surge prediction deviations caused by boundary simplification.

[0048] Furthermore, the construction of the aerodynamic parameter transmission channel specifically includes: the one-dimensional non-adiabatic pipeline dynamics model transmitting right-moving Riemann invariants to the three-dimensional conjugate flow-thermal coupling model, thereby updating the inlet pressure and airflow velocity of the three-dimensional conjugate flow-thermal coupling model; the three-dimensional conjugate flow-thermal coupling model feeding back left-moving Riemann invariants to the one-dimensional non-adiabatic pipeline dynamics model, realizing the continuous transmission of pressure waves without reflection.

[0049] In this embodiment, the construction of the thermal parameter transfer channel specifically includes: the one-dimensional non-adiabatic pipeline dynamics model outputs the total temperature of the interface nodes to the three-dimensional conjugate flow thermal coupling model as the three-dimensional inlet thermal boundary; the three-dimensional conjugate flow thermal coupling model feeds back the surface weighted average total temperature and real-time mass flow rate of the interface to the one-dimensional non-adiabatic pipeline dynamics model, which are used to iteratively update the energy state parameters of the one-dimensional non-adiabatic pipeline dynamics model.

[0050] By using bidirectional transmission of Riemann invariants to achieve pressure wave non-reflection transmission, false reflection waves and numerical oscillations at the interface can be avoided, ensuring the stability of one-dimensional-three-dimensional coupled simulation and accurately capturing the evolution law of pressure wave system during surge.

[0051] Constructing a dynamic thermodynamic boundary and energy feedback closed loop can break the traditional adiabatic coupling assumption, accurately reproduce the interaction between unsteady heat transfer in pipelines and conjugate heat transfer inside the compressor, and improve the accuracy of temperature field calculation under hot conditions.

[0052] A coupling procedure is defined at the physical interface between the inlet / outlet of the three-dimensional fluid domain and the dynamics model of the one-dimensional non-adiabatic piping. At any time step... Internally, the data interaction logic is as follows:

[0053] (1) Aerodynamic parameter transmission channel: sending right-moving Riemann invariants from one dimension to three dimensions (in For the local speed of sound, For flow rate, (Specific heat ratio), used to update the three-dimensional inlet pressure and velocity; three-dimensional to one-dimensional feedback of left-moving Riemann invariants. This ensures the pressure wave is transmitted without reflection.

[0054] (2) Thermal parameter transfer channel: one-dimensional to three-dimensional transmission of total temperature of interface nodes As a three-dimensional inlet thermal boundary; the surface-weighted average total temperature of the three-dimensional to one-dimensional feedback interface. Mass flow rate is used to update the energy state of a one-dimensional system.

[0055] Synchronous exchange of aerodynamic and thermodynamic information is completed within a fixed time step, realizing dynamic matching of acoustic and thermal characteristics of a one-dimensional non-adiabatic pipeline dynamic model with three-dimensional compressor flow characteristics, ensuring the temporal consistency and physical authenticity of simulation results.

[0056] By quantifying and interacting physical quantities such as surface-weighted average total temperature and real-time mass flow rate, strict conservation of energy and mass is achieved between models of different dimensions, effectively reducing numerical errors caused by cross-scale coupling and improving simulation reliability.

[0057] Furthermore, the three-dimensional fluid domain and the one-dimensional non-adiabatic pipeline dynamic model adopt a microsecond-level calculation time step, while the three-dimensional solid domain adopts a millisecond-level calculation time step; the three-dimensional fluid domain and the three-dimensional solid domain interact with heat flux data and temperature field distribution data according to a preset thermal coupling synchronization period.

[0058] In this embodiment, the target operating speed of the compressor is set to be To simulate the hot-immersion condition of the turbocharger, the initial temperature field of the three-dimensional solid domain was uniformly initialized to... (Fluid temperature higher than normal).

[0059] A time-step decoupling strategy was adopted to initiate the transient solution: a microsecond-level time step was used for the three-dimensional fluid domain (including 1D and 3D), and a millisecond-level time step was used for the three-dimensional solid domain. After the simulation ran smoothly, the cross-sectional area of ​​the one-dimensional end throttle valve was linearly reduced from fully open to its minimum value within 0.5 seconds using a control function.

[0060] The one-dimensional-three-dimensional fluid-thermal coupling calculation adopts a time-step decoupling solution strategy as follows: a first microsecond-level time step is used for the three-dimensional fluid domain and the one-dimensional non-adiabatic pipeline dynamic model, and a second millisecond-level time step is used for the three-dimensional solid domain; the three-dimensional fluid domain and the three-dimensional solid domain exchange heat flux and temperature field data in a preset synchronization period.

[0061] In this embodiment, a time-step decoupling strategy is employed for transient solutions. The three-dimensional fluid domain and the one-dimensional non-adiabatic pipeline dynamics model both use microsecond-level computation time steps to capture high-frequency transient flows such as pressure wave propagation and vortex structure evolution. The three-dimensional solid domain uses millisecond-level computation time steps to match the low-frequency, slowly varying characteristics of solid thermal inertia and heat conduction. After the simulation stabilizes, a preset control function command is used to drive the flow cross-sectional area of ​​the throttling valve at the end of the one-dimensional non-adiabatic pipeline dynamics model to linearly close from fully open to a minimum flow area within 0.5 seconds, actively inducing system surge.

[0062] The differentiated time step design, which operates at the microsecond level for fluids and the millisecond level for solids, accurately captures high-frequency transient fluctuations in aerodynamics while avoiding unnecessary small time iterations in the three-dimensional solid domain. This significantly reduces the overall computational cost and achieves a balance between accuracy and efficiency.

[0063] By initializing the entire three-dimensional solid domain to a high temperature of 120℃, the thermal soaking state after the engine stops is realistically reproduced, making the simulation environment closer to the real heat accumulation condition and improving the physical realism of the thermal-surge coupling simulation.

[0064] By adopting a control strategy that linearly reduces the flow area of ​​the throttle valve in 0.5 seconds, the surge condition can be controlled and reproducibly induced, making it easier for the system to extract the complete instability evolution process and critical surge boundary.

[0065] The three-dimensional fluid domain and the three-dimensional solid domain exchange heat flux and temperature field at a fixed period. While ensuring the accuracy of thermal coupling, it avoids the waste of computing power caused by high-frequency synchronization, and effectively improves the stability, convergence and engineering practicality of coupled simulation.

[0066] Monitoring results show that the high temperature of the impeller and back plate continuously heats the main intake airflow, causing the gas to expand and alter the local Mach number. When the valve is closed for 0.35 seconds, significant low-frequency oscillations at the system's Helmholtz resonant frequency (approximately 40Hz) and a deep-breathing phenomenon occur in the inlet and outlet flow rates, triggering surge. Compared to the adiabatic simulation that ignores heat transfer, the actual surge boundary, considering thermal effects, shifts towards the high-flow-rate region by approximately [missing information]. This indicates that the hot soaking effect worsened the compressor's stability.

[0067] Furthermore, the structural optimization design of the compressor specifically includes at least one of aerodynamic profile optimization and thermal management structure optimization.

[0068] Aerodynamic profile optimization involves modifying the aerodynamic profile of the compressor impeller tip based on the flow separation characteristics induced by heat. Thermal management structure optimization involves adding an air insulation cavity or cooling channel on the inner side of the compressor back plate or the back of the diffuser flow channel based on the temperature gradient distribution of the three-dimensional solid domain, in order to block the conduction of heat to the intake mainstream area.

[0069] Based on the evolution law of airflow separation induced by high temperature, the aerodynamic profile of the compressor impeller tip is modified to complete the optimization of the compressor aerodynamic profile.

[0070] By specifically modifying the aerodynamic profile of the impeller tip based on the flow separation characteristics induced by thermal effects, the development of tip leakage flow and secondary flow can be effectively suppressed, the adverse pressure gradient and airflow separation phenomenon caused by high temperature region can be weakened, the internal flow uniformity of compressor can be improved, the aerodynamic work efficiency can be increased, the compressor stable operating margin can be widened from the aerodynamic level, and the occurrence of thermal surge can be effectively delayed.

[0071] Three-dimensional transient flow field and solid temperature field data were extracted at the critical moment of surge. Analysis revealed that thermal expansion led to a rapid thickening of the boundary layer, inducing severe flow separation at the impeller leading edge and diffuser hub side. Based on this, the following structural optimization was performed:

[0072] (1) Thermal management structure optimization: Modify the three-dimensional solid domain model, and add a width of [missing information] between the back plate and the high-temperature bearing body. The air insulation cavity utilizes the low thermal conductivity of air to cut off the heat flow path from the turbine end to the compressor.

[0073] (2) Aerodynamic profile optimization: For the intake angle deflected by heat, fine-tune the installation angle of the impeller leading edge and the blade tip sweep profile.

[0074] The optimized model was then validated using steps S1 to S5. The results showed that after implementing the above collaborative design, the gas temperature at the impeller inlet root decreased. Under the same harsh hot immersion environment, the surge boundary flow of the optimized scheme is widened to the left by 8.5% compared to the original scheme. The method of this invention successfully guides the effective stabilization of the compressor in complex multi-physics environments.

[0075] Aerodynamic profile optimization and thermal management structure optimization can be implemented separately or in combination to achieve the dual optimization goals of aerodynamic stability enhancement and thermal control vibration suppression. From the two dimensions of flow and heat transfer, they jointly suppress the causes of thermal surge instability, and improve the working stability, reliability and environmental adaptability of the compressor under harsh conditions such as high temperature, low speed and hot immersion.

[0076] Based on the three-dimensional solid domain temperature gradient distribution characteristics, an air insulation cavity or fluid cooling channel is added to the inner side of the compressor back plate or the back of the diffuser flow channel to block heat conduction and diffusion to the main intake area, thus completing the optimization of the compressor thermal management structure.

[0077] Based on the precise identification of heat accumulation areas according to the temperature gradient distribution in the three-dimensional solid domain, by adding air insulation chambers or cooling channels, the heat in high-temperature areas such as the back plate and diffuser can be effectively blocked from being conducted and diffused to the mainstream intake area, thereby reducing the mainstream intake temperature, weakening the adverse effects of heat immersion on the aerodynamic boundary, improving the flow field stability under thermal conditions, and achieving compressor expansion, stability and efficiency enhancement from the thermal control level.

[0078] The present invention also proposes a compressor design system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement any of the above.

[0079] The present invention achieves the following beneficial technical effects:

[0080] 1. Breaking through the theoretical blind spots of traditional thermal insulation design: This invention innovatively introduces a one-dimensional non-insulated pipeline dynamic model and a three-dimensional conjugate flow thermal coupling model, and couples them through a "total temperature / mass flow rate" thermal channel. This method can accurately reproduce the unsteady effects of heat load (such as turbine hot immersion) on compressor aerodynamic performance, making the simulation environment highly consistent with real harsh operating conditions, and significantly improving the fidelity of surge prediction under extreme conditions.

[0081] 2. Balancing the accuracy and efficiency of multiphysics calculations: A one-dimensional reduced model is used to replace the massive three-dimensional fluid domain of the peripheral pipeline, and cross-dimensional acoustic wave reflections are eliminated through Riemann invariants; at the same time, a time-step decoupling solution strategy is adopted for the fluid field (extremely fast evolution) and the solid temperature field (slow evolution), which greatly saves computational resources without sacrificing the accuracy of transient flow field capture.

[0082] 3. Achieves deep synergy between thermal management and aerodynamic design: This invention not only optimizes traditional blade aerodynamic profiles but also accurately locates heat source paths based on the temperature gradient field of the three-dimensional solid domain, guiding the design of thermal structures such as air insulation chambers in key locations like the back disk. By simultaneously addressing both "heat flow blocking" and "airflow optimization," it fundamentally enhances the compressor's anti-surge capability.

[0083] The present invention also proposes a storage medium storing a computer program, which, when executed by a processor, implements any one of the flow-thermal coupling compressor design methods.

[0084] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by computer program instructions and related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Dual Data SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), Rambus Direct RAM (RDRAM), Direct Memory Bus Dynamic RAM (DRDRAM), and Memory Bus Dynamic RAM (RDRAM). The various embodiments described in this specification are presented in a progressive manner, with reference allowed to each other for similar or identical parts. Each embodiment focuses on its differences from other embodiments. In particular, embodiments of apparatus, devices, and non-volatile computer storage media are described simply because they are substantially similar to method embodiments; relevant details can be found in the descriptions of the method embodiments.

[0085] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A method for designing a flow-thermal coupled compressor, characterized in that, include: A three-dimensional conjugate flow-thermal coupling model is constructed based on a compressor. The three-dimensional conjugate flow-thermal coupling model includes a three-dimensional fluid domain and a three-dimensional solid domain. A conjugate heat transfer interface is provided between the three-dimensional fluid domain and the three-dimensional solid domain. A one-dimensional non-adiabatic pipeline dynamic model is constructed based on the compressor peripheral pipeline. The one-dimensional non-adiabatic pipeline dynamic model integrates the mass conservation equation, the momentum conservation equation, and the energy conservation equation with an unsteady heat transfer source term. At the interface between the three-dimensional conjugate flow thermal coupling model and the one-dimensional non-adiabatic pipeline dynamics model, a dual coupling interface is constructed. The dual coupling interface has an aerodynamic parameter transmission channel for transmitting wave system information and a thermodynamic parameter transmission channel for transmitting energy information. Based on the dual coupling interface, one-dimensional-three-dimensional spatiotemporal synchronous flow-thermal coupling iterative calculation is performed. Wave system information and energy information are exchanged synchronously in each time step to realize pressure wave non-reflection transmission and synchronously solve for the transient flow field distribution and temperature field distribution of the compressor system. Based on the transient flow field distribution and the temperature field distribution, the initial thermal boundary conditions for thermal accumulation are set. By dynamically adjusting the flow area of ​​the throttle valve at the end of the one-dimensional non-insulated pipeline, the dynamic simulation of thermal surge under varying operating conditions is carried out to extract the internal flow field instability evolution characteristics and critical surge boundary data of the compressor. Based on the critical surge boundary data and the internal flow field instability evolution characteristics, the heat accumulation region was identified, and the compressor structure was optimized.

2. The flow-thermal coupled compressor design method according to claim 1, characterized in that, The three-dimensional fluid domain includes an air intake, an impeller flow channel, a diffuser, and a volute cavity; and / or the three-dimensional solid domain includes an aluminum alloy impeller body, a back disk, and a volute outer shell body.

3. The flow-thermal coupled compressor design method according to claim 1, characterized in that, The unsteady heat source term is used to solve the real-time transient heat transfer between the airflow inside the pipe and the pipe wall; the real-time transient heat transfer is calculated based on the set physical parameters of the pipe wall material, the pipe wall thickness parameters and the dynamic convection heat transfer coefficient, and the dynamic convection heat transfer coefficient is updated in real time according to the Reynolds number of the transient airflow inside the pipe.

4. The flow-thermal coupled compressor design method according to claim 1, characterized in that, The construction of the aerodynamic parameter transmission channel specifically includes: the one-dimensional non-adiabatic pipeline dynamics model transmitting right-moving Riemann invariants to the three-dimensional conjugate flow-thermal coupling model, thereby updating the inlet pressure and airflow velocity of the three-dimensional conjugate flow-thermal coupling model; the three-dimensional conjugate flow-thermal coupling model feeding back left-moving Riemann invariants to the one-dimensional non-adiabatic pipeline dynamics model, realizing continuous pressure wave transmission without reflection.

5. The flow-thermal coupled compressor design method according to claim 1, characterized in that, The construction of the thermal parameter transfer channel specifically includes: the one-dimensional non-adiabatic pipeline dynamic model outputs the total temperature of the interface nodes to the three-dimensional conjugate flow thermal coupling model as the three-dimensional inlet thermal boundary; the three-dimensional conjugate flow thermal coupling model feeds back the surface weighted average total temperature and real-time mass flow rate of the interface to the one-dimensional non-adiabatic pipeline dynamic model, which are used to iteratively update the energy state parameters of the one-dimensional non-adiabatic pipeline dynamic model system.

6. The flow-thermal coupled compressor design method according to claim 1, characterized in that, The three-dimensional fluid domain and the one-dimensional non-adiabatic pipeline dynamic model use a microsecond-level calculation time step, while the three-dimensional solid domain uses a millisecond-level calculation time step. The three-dimensional fluid domain and the three-dimensional solid domain exchange heat flux data and temperature field distribution data according to a preset thermal coupling synchronization period.

7. The flow-thermal coupled compressor design method according to claim 1, characterized in that, Structural optimization design of compressors specifically includes at least one of aerodynamic profile optimization and thermal management structure optimization.

8. The flow-thermal coupled compressor design method according to claim 7, characterized in that, Based on the evolution law of airflow separation induced by high temperature, the aerodynamic profile of the compressor impeller tip is modified to complete the optimization of the compressor aerodynamic profile.

9. The flow-thermal coupled compressor design method according to claim 7, characterized in that, Based on the three-dimensional solid domain temperature gradient distribution characteristics, an air insulation cavity or fluid cooling channel is added to the inner side of the compressor back plate or the back of the diffuser flow channel to block heat conduction and diffusion to the main intake area, thus completing the optimization of the compressor thermal management structure.

10. A compressor design system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the flow-thermal coupling compressor design method as described in any one of claims 1 to 9.

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