Numerical investigation and optimal design of transpiration cooling plate structure for gradient porosity

In this paper, a novel gradient porosity transpiration cooling plate structure (GP-TCPS) is proposed to address the heat transfer deterioration phenomenon owing to non-uniform local temperature distribution in transpiration cooling plate structure (TCPS). The flow and heat transfer (FAHT) of the GP-TCPS were analyzed qualitatively and quantitatively by computational fluid dynamics (CFD) and response surface method (RSM). The effects of various parameters on the injection pressure (Pc) and average cooling efficiency (eta ave) of the GP-TCPS were investigated, ultimately identifying optimal structural parameters. The results show that the GP-TCPS significantly improves the temperature uniformity by 20.58-23.78 % compared to uniform porosity transpiration cooling plate structure (UP-TCPS) at low coolant mass flow rates. Compared with the UP-TCPS, the Pc of the GPTCPS decreases by 84.5-86.2 %, and the deviation of the eta ave is 1.3-2.4 %. The RSM indicates that the most important parameters affecting the Pc and eta ave of the GP-TCPS are average particle diameter and the thickness of porous media, respectively. The Pc of the optimized structure is reduced by 57.19-77.39 %, the eta ave is increased by 7.72-9.42 %, and the temperature uniformity is increased by 52.33-66.14 %. The results provide valuable insights into the mechanism of TCPS and offer promising solutions to mitigate heat transfer deterioration.