High-fidelity LES of Pin Fin-Jet Configuration Effects on Supercritical N-Decane Flow and Heat Transfer in Regenerative Cooling Channels

Active regenerative cooling technology is well-suited for extreme operating conditions characterized by high temperatures and intense thermal loads, serving as a highly effective approach for reducing combustion chamber wall temperatures. Large Eddy Simulation (LES) is employed to investigate the thermo-hydraulic characteristics of supercritical n-decane in a jet-regeneration cooling channel with the pin fin, focusing on the critical yet underexplored effects of pin fin-jet spatial configurations. The results indicate that the fluid flow within the jetregeneration cooling channel gradually evolves towards a quasi-steady state, accompanied by the breakdown process of large-scale vortex structures into small-scale turbulence. The introduction of the pin fin significantly enhances the distribution stability of the thermophysical properties of supercritical n-decane, facilitating uniform temperature field transfer and thereby boosting the overall heat transfer efficiency of the channel. Compared to the pin fin placement schemes in front of and directly below the jet, positioning the pin fin behind the jet effectively leverages the high turbulence intensity in the jet wake region, achieving an optimal balance between heat transfer enhancement and flow resistance suppression. Compared to the flat channel, this configuration leads to an average increase of 3.29 % in the Nusselt number (Nu) throughout 0-1.8 s, with an instantaneous maximum enhancement of 32.6 %. The Thermal-Hydraulic Performance Factor (HTPF) is notably superior to the benchmark value of unity, underscoring its comprehensive performance advantages.