Numerical investigation on energy loss within phase-change transpiration cooling system considering particle deformation

A numerical model of phase-change transpiration cooling incorporating particle thermal deformation was established to better represent physical conditions at high temperatures. Using entropy generation analysis, the coupled effects of particle deformation, heat flux nonuniformity, coolant mass flux, and inlet temperature on flow and heat transfer characteristics, as well as system energy loss were systematically investigated. Particle thermal deformation reduced porosity and increased particle diameter, particularly in high-heat-flux regions, thereby exacerbating coolant maldistribution and increasing total dissipation loss by 2.3%. Increasing heat flux nonuniformity from 0.25 to 1.00 increased total dissipation loss by 78.6%, driven by the synergistic growth of flow- and thermal-related entropy generation. Raising the coolant mass flux from 0.4 to 0.7 kg/(m2·s) suppressed particle deformation, improved flow uniformity, and reduced total dissipation loss by 39.2%. Increasing the inlet temperature from 280 K to 340 K reduced total dissipation loss by 53.3% but increased the wall temperature by approximately 55 K, revealing a trade-off between irreversibility reduction and cooling performance. These findings quantify the evolution of entropy generation under multifactor coupling and provide theoretical guidance for optimizing phase-change transpiration cooling systems.