不同材料发汗冷却结构下氢冷却性能

为了实现航空航天等领域高温大热流燃烧装置的有效冷却，研究了不同材料和工艺制成的发汗冷却结构在高温高热流密度下，氢的发汗冷却性能。模拟高压推力室的结构特点和高热流设计发汗冷却试验件，用电弧加热主流空气模拟高温燃气、以氢气为发汗冷却剂对多孔陶瓷、烧结多孔不锈钢和多孔层板材料进行了33次172 s热试验研究。试验的材料设计孔隙率为10%~40%，燃烧室压力为2.7~8.4 MPa，主流燃气温度约为3 600 K，主流空气流量为220~1 490 g/s，冷却氢气流量为9.6~57 g/s，注入率为0.005~0.029。试验结果表明:当冷却剂氢注入率为1%时，主流与多孔陶瓷材料壁面和粉末冶金多孔结构壁面之间的换热分别减少了30%和70%以上；当注入率为3%时，主流与光刻多孔层间结构壁面之间的换热也能降低60%。证明氢发汗冷却可以有效减小壁面与燃气之间的对流热流。最后还总结得出了常温氢气对高压大热流环境进行发汗冷却的性能关联式。 

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.