Experimental investigation on the cooling performance of a solid hybrid gel with self-transpiration cooling at high temperature

Abstract

Transpiration cooling technology represents a viable cooling method for ultra-high temperature or high heat flux environments, offering high cooling efficiency. In previous studies, coolants were primarily in the form of gases and liquids. Therefore, the exploration of solid coolants remains a promising avenue for further research. This paper utilizes a compound with a substantial heat absorption capacity upon decomposition to prepare a solid hybrid gel as a coolant, and constructs a transpiration cooling structure with a high porosity zirconia foam as the coolant carrier and a stainless-steel wire mesh panel as the outer porous panel. Subsequently, the cooling structure was subjected to a thermal load experiment at a high temperature of 1654 K for a period of 1600 s. The present study offers novel and valuable insights by comparing the results with those of previous studies on hydrogel and ammonium carbonate, which have been extensively investigated with strong applicability: Hybrid gel stored at room temperature demonstrate superior long-term stability compared to hydrogel and ammonium carbonate. Hybrid gel, ammonium carbonate, and hydrogel demonstrated the capacity to cool the underside of the structure with a level of efficiency exceeding 30 % for a duration exceeding 1000 s under the experiment conditions. Among the hybrid gel, ammonium carbonate, and hydrogel, the hybrid gel exhibited the most efficient cooling of the surface of the specimen, achieving a rate of 10.6 %. Following an increase in the porosity of the porous panel from 20 μm to 120 μm, the hybrid gel has been observed to enhance the cooling efficiency of the specimen surface by 1.6 %, whereas ammonium carbonate and hydrogel do not possess this capability.