LES simulation and experimental study on hydrothermal performance of a pulsatile impinging jet on different pin-finned configurations mounted flat plate

Jet impingement cooling is a vital method for prolonging the service life of components subjected to high thermal loads. The cooling performance of gas jets depends significantly on the gas and surface physical properties, including the injection Reynolds number, Injection frequency, and fines configurations, making it essential to quantify their effects. Despite this, limited research exists on predicting the cooling capacity of pulsatile gas jets under varying conditions. This work presents a numerical study comparing the accuracy of various turbulence models in predicting the hydrothermal performance of the jet and its impact on both local and overall heat transfer. The analysis employs RNG k − ɛ and Large Eddy Simulation (LES) models tailored to the system's geometry and boundary conditions. Time-averaged Nusselt number distribution on the surfaces of square pin fins at different vertical sections, the average Nusselt numbers are approximately 61.18 at y/h = 0.9, 59.68 at y/h = 0.5, and 19.73 at y/h = 0.01, indicating that the convective heat transfer coefficient near the pin tip is about 210% higher than at the base. The comparison of different pin-fin configurations shows that the elliptic pin surface provides the highest average Nusselt number among the investigated cases. This enhanced heat transfer is attributed to the elliptic geometry, which promotes stronger flow mixing, enhances vortex formation, and increases disturbance of the thermal boundary layer around the pins.