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采用超临界压力碳氢燃料作为冷却剂的再生冷却技术是超声速燃烧冲压发动机的一种重要热防护技术。本文以工程碳氢燃料为工质,在内径2 mm的竖直圆管内进行了不同流向、流量、压力、热流密度条件下的对流换热实验研究。结果表明,在较高进口Re数条件下,相同热流密度时,向上流动和向下流动工况的壁温分布没有明显差别;在较低进口Re条件下,向上流动工况的局部壁温远高于对应向下流动工况,发生传热恶化。研究表明该碳氢燃料的临界Bo*数判据为3×10~(-7)。拟合得到适用于该碳氢燃料的对流换热关联式。
Regenerative cooling technology using supercritical pressure hydrocarbon fuel as a coolant is an important thermal protection technology for supersonic combustion ramjet engines. In this paper, engineering hydrocarbon fuel is used as working fluid, and convection heat transfer experiments under different flow direction, flow rate, pressure and heat flux are carried out in a vertical tube with an inner diameter of 2 mm. The results show that there is no significant difference in wall temperature distribution between upward flow and downward flow under the condition of higher inlet Re number and the same heat flux. Under the condition of lower inlet Re, Higher than the corresponding downward flow conditions, deterioration of heat transfer occurs. The research shows that the critical Bo * number of the hydrocarbon fuel is 3 × 10 -7. Fitting to obtain the appropriate correlation for the hydrocarbon fuel convection heat transfer.