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Acta Aeronautica et Astronautica Sinica

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Adaptive relaxation coupling simulation method for thermochemical nonequilibrium flow

Ming-Song DING1,Qing-Zong Liu2, Peng LI4,Jie MEI1,Yang-Ao-Xiao FU1   

  • Received:2025-11-07 Revised:2025-12-29 Online:2025-12-29 Published:2025-12-29
  • Contact: Qing-Zong Liu
  • Supported by:
    National Numerical Windtunnel

Abstract: The efficiency of numerical simulation of thermochemical non-equilibrium flow has always been one of the pain points in engineering applications. Based on the time-consuming analysis of thermochemical non-equilibrium flow simulation, an adaptive relaxation coupling simulation method of thermochemical non-equilibrium flow was established by capturing and judging the flow field characteristics or iterative characteristics. The accuracy and efficiency of this method were tested and analyzed under different physical and chemical models, as well as different thermochemical non-equilibrium flow characteristics. The results show that, the time-consuming ratio of non-equilibrium source term processing, multi-component gas energy function and transport coefficient calculation could reach 62.03% under the conditions of this paper. The computational efficiency of numerical simulation was significantly improved by using the adaptive relaxation coupling simulation method, which can be improved by up to 84.16%. This method does not reduce the convergence and accuracy of numerical iteration, and has the same calculation fidelity and accuracy as the coupling simulation method of full physical models. It can be easily implemented on various static or dynamic software architectures without changing the computational domain dynamically and greatly adjusting the logical structure or computational flow. This method is more effective in fine physical and chemical model, and can partly solve the difficulty of balancing computational accuracy and efficiency of complex engineering problems.

Key words: hypersonic flow, high temperature gas effect, thermochemical non-equilibrium, adaptive relaxation coupling, numerical simulation