Study on the Unsteady Transpiration Cooling Within the Supersonic Mainstream
Based on the technique of"solving regionally and couping at the interfaces",this paper proposed a coupled model to numerically investigate the transient heat and speices transport during the phase change transpiring cooling process using the water as the working fluid.The results indicated that maldistribution of coolant would occur due to the unsteady and nonuniform heat flux from the supersonic mainstream,and the maldistribution of coolant would inherently exacerbate during the applications.After 30 s of the transpiration cooling,with the coolant flow being squeezed to the downstream,the peak flow rate exceeds the inlet flow rate by the factor of 9.1,and the area of low flow rate region filled by evaporated coolant occupied over 76％of all.The increase flow rate would induce a liquid film at the interface,which could reduce the thermal insulating properties,thus the surface heatflux on the porous region filled with the liquid phase coolant(about 0.15 MW.m-2)would be higher than the region filled with evaporated coolant(about 0.11 MW.m-2).However,the cooling capacity of gaseous fluid is relatively low,and the temperature of porous strucure filled by gasous coolant would rapidly increase.Therefore,regulating the inlet coolant flow would be nescessary to mitigate the effects of local coolant evaporation.
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