旋流通道内超临界氮的换热性能研究OA北大核心CSTPCD

In order to study the heat transfer performance of supercritical nitrogen in spiral tube.By means of numerical simulation and experiments,the changes of flow and heat transfer caused by physical properties of supercritical nitrogen along and around the spiral tube,the influences of flow and structural parameters on heat transfer coefficient h,fluid temperature Tf,wall temperature Tw and pressure P1 were discussed,the sensitivity of each structural parameter is quantitatively analyzed.The results show that:when the fluid temperature is near the critical temperature127.15 K,heat transfer coefficient reaches the peak value.The maximum sensitivity values of pipe diameter d to h,Tout and P1 are 2.47,0.42 and 2.15,indicating that the change of d value has the greatest effect on flow heat transfer.The data were processed and the heat transfer correlation formula of supercritical nitrogen was fitted based on spiral tube structure characteristics,the maximum error between the simulated value and the formula value was 12%.The research results can provide reference for the application and promotion of spiral tube heat exchangers.