论文部分内容阅读
本文对超临界压力下正癸烷在内径为0.95 mm和2 mm竖直微细圆管内对流换热进行了实验研究.入口压力p_(in)=3 MPa和入口雷诺数Re_(in)=4000时,分析了管径、变物性、浮升力和加速对对流换热的影响.结果表明:在所研究的工况范围内,对于0.95 mm内径圆管,浮升力和加速对换热的影响可忽略,对流换热主要受变物性的影响;而对于2mm内径圆管,在高热流密度时,浮升力对正癸烷的对流换热影响很大,向上流动时引起换热恶化,向下流动时引起换热强化,加速对流动换热的影响可忽略.
In this paper, the experimental study on the convective heat transfer of n-decane in the 0.95 mm and 2 mm vertical micro-tubes with supercritical pressure is carried out.The inlet pressure p_ (in) = 3 MPa and the inlet Reynolds number Re_ (in) = 4000 , The effects of tube diameter, physical property, lift force and acceleration on the convective heat transfer are analyzed.The results show that the influence of lift force and acceleration on heat transfer is negligible for 0.95 mm internal diameter pipe , And the convective heat transfer is mainly affected by the variation of the physical properties. For the 2 mm ID tubes, the convective heat transfer of n-decane is greatly affected by the buoyant force at high heat flux density, which causes the heat transfer to deteriorate when flowing upward. Causing heat transfer enhancement, accelerated the impact on the flow heat transfer can be ignored.