Cooling performance of hydrogen for transpiration cooling structure made by different materials

In order to achieve effective cooling of high temperature and large heat flux combustion devices in aerospace and other fields, the transpiration cooling performance of hydrogen for structure made by different materials and processes under high temperature and high flux density was studied.To simulate the structural characteristics and high heat flow of the high⁃pressure thrust chamber, a transpiration⁃cooling test piece was designed, and the mainstream air was heated by an electric arc to generate high⁃temperature gas.Hydrogen perspiration coolant was applied to 33 thermal tests for 172 seconds on porous ceramics, sintered porous stainless steel and porous laminate materials.The tested material had a porosity of 10%-40%, a combustion chamber pressure of 2.7-8.4 MPa, a mainstream gas temperature of about 3 600 K, a mainstream air flow rate of 220-1 490 g/s, a cooling hydrogen flow rate of 9.6-57 g/s, and an injection rate of 0.005-0.029.Test results showed that when the injection rate of hydrogen perspiration cooling was 1%, the heat exchange between the mainstream high⁃temperature gas and the walls of both the porous ceramics and the sintered porous stainless steel was reduced by more than 30% and 70%, respectively; when the injection rate of hydrogen perspiration cooling was 3%, the heat exchange between the mainstream high⁃temperature gas and the walls of the porous laminate materials was reduced by more than 60%.Hydrogen transpiration cooling can effectively reduce the convective heat flow between the wall and the gas.Furthermore, the performance correlation of high pressure, large heat flow and normal temperature hydrogen perspiration cooling was summarized. © 2022, Editorial Department of Journal of Aerospace Power. All right reserved.