三角槽道层流脉动流的流场分布特性及热量输运规律研究OA北大核心CSTPCD

In order to analyze the composite enhanced heat transfer mechanism of pulsating flow in the small-scale channel of periodic expansion and contraction,the flow characteristics and heat transport rules were studied for the laminar pulsating flow in the triangular grooved channel.By taking"secondary flow"as the starting point,and"vortex and vortex motion"as the viewing angle,the effects of Strouhal number(St)and pulsating amplitude(A)on laminar pulsating flow in the triangular grooved channel and the heat transfer process were analyzed,and the correlation between the intensity of secondary flow and the heat transfer enhancement of laminar flow was revealed.The results show that the field coordination angle(β)can be reduced by more than 5° by adjusting St and A to enhance the synergy between temperature gradient and velocity vector,and the heat transfer efficiency can be improved by more than 55%.Otherwise,St is set to optimize the path of the vortex,and there is an optimal St value which can increase the heat transfer efficiency by more than 40%.Pulsating amplitude is set to improve the strength of the vortex,and the maximum heat transfer efficiency is increased by nearly 15%when A is less than 100%.The effect of Strouhal number and pulsating amplitude on vortex motion can be fed back quantitatively by secondary flow intensity so as to find optimal value matching between St and A,and effectively control heat transfer efficiency and energy consumption.The research results can provide reference for solving the problems of flow and heat transfer in engineering environment(molten salt system pipelines and molten salt electric heater heat exchange pipes of CSP power station)with high viscosity and low flow rate,or in the small-scale special-shaped pipelines.