An Investigation on Heat Transfer Characteristics of Fully Developed Flow in Bilaterally Heated Narrow Annuli

Numerical research was carried out on the convection heat transfer characteristics in bilater-ally heated annular channel with narrow gap under the conditions of fully developed flow,where the inner and outer walls are heated by uniform but unequal heat fluxes.Calculation results show that the ratio of the inner wall heat flux to the outer wall heat flux has great effects on the heat transfer characteristics in bilater-ally heated narrow annuli.With the increase of the inner wall heated flux,the heat transfer coefficient at the outer wall of the inner tube will decrease,while the heat transfer coefficient at the inner wall of outer tube will increase.These numerical results are in good agreement with some experimental results in open litera-tures.Numerical results also show that the decrease of the annuli gap will yield heat transfer deterioration during flowing in narrow annular channels.