Large-eddy simulation of transpiration cooling in turbulent channel with porous wall

Transpiration cooling is an excellent and effective cooling technology and is one of the optional technologies for thermal protection systems of hypersonic vehicles. This paper presents a numerical investigation on transpiration cooling of a turbulence channel, the behaviors of vorticities in hot mainstream are investigated by using large-eddy simulation (LES) that incorporate the Darcy-Forchheimer model and the local non-equilibrium thermal model. The instability of the boundary layer obtained in the experiment is simulated and analyzed by numerical simulation. Both experiments and simulations can observe that the coolant and the mainstreams form the jelly roll when the coolant is injected into the hot mainstream, and this phenomenon is inferred to be Kelvin-Helmholtz instability. Periodic vortex behavior was observed experimentally and numerically, each cycle is 1.25 ms when the injection rate is 1%, and there are three processes of vortex generation, development and fragmentation in a complete cycle.