Experimental and simulation study on cooling heat transfer characteristics in narrow annuli fluid channel

Under the condition of 6 different equivalent diameters, using water as working media, the experiments of cooling heat transfer in annular channel is studied. The results show that the force convention heat transfer in narrow annuli is different with that in conventional channel, in former case the turbulent zone significantly ahead of schedule. When the equivalent diameter is 0.94 mm, only turbulent flow region exists in the channel. Narrow annuli can enhance or inhibit the heat transfer. Simulation and experimental results are in good agreement. The change of inner diameter core pipe has effect on the narrow annuli heat transfer.