Numerical and experimental studies on an improved simulated annealing algorithm for inverse heat flux identification in transpiration cooling thermal protection systems

Accurate identification of heat flux in transpiration cooling thermal protection systems (TPS) is critical for precise temperature control and optimization of cooling efficiency during active control processes. However, identifying surface heat flux in such systems poses more significant challenges than conventional inverse heat conduction problems (IHCP), primarily due to the complex interactions among high-Mach-number flows, compressible outflow, and microscale percolation effects in a porous medium. In this paper, the inverse heat infiltration coupling problem (IHICPP), which focuses on identifying surface heat flux in porous transpiration cooling TPS, is analyzed in detail. To transform HICPP into an optimization problem, a local thermal non-equilibrium model is employed to simulate the direct problem. The objective function is formulated using the least-squares method. An improved simulated annealing algorithm (ISAA) is proposed, which leverages gradient iteration within the simulated annealing framework to enhance identification accuracy and computational efficiency. The ISAA demonstrates merit performance across various surface heat flux waveforms and TPS thicknesses, achieving stable and reliable results. This study serves as a valuable reference for active control and optimization of TPS, offering a robust methodology for IHICPP in high-Mach-number aircraft.