Experimental study of phase change transpiration cooling with varying pore distributions under hot gas flow

Phase change transpiration cooling demonstrates significant potential as a promising thermal management strategy for addressing thermal loads on high-temperature components operating under high-enthalpy and prolonged heating conditions. This investigation establishes an experimental platform to evaluate phase change transpiration cooling performance on thermally challenged surfaces subjected to high-speed hot gas flow. Utilizing sintered copper porous media as matrix materials with liquid water and kerosene as coolants, the study systematically investigates the synergistic effects of pore distribution, coolant properties, mass flow rate, and incoming flow temperature on cooling performance. Experimental data reveal that water-cooled matrices exhibit a peak cooling efficiency of 0.91. Comparative analysis indicates kerosene cooling attains a maximum average cooling efficiency of 0.76 accompanied by superior thermal homogeneity across the matrix surface, albeit lower cooling capacity. Three characteristic cooling regimes emerge with increasing coolant flow and mainstream temperature variations have little impact on the transpiration cooling performance when the matrix is fully cooled. Critical findings suggest that porous media with reduced pore dimensions and higher porosity demonstrate enhanced thermal performance through elevated capillary and boiling limits, and superior coking resistance under kerosene cooling. This work provides reliable guidance for further research into the design and optimization of transpiration cooling systems in practical applications under high-enthalpy heating conditions.