双侧加热环形窄缝通道内单相水的流动传热特性研究

对环形窄缝通道内单相水在双面处于不同的加热热流密度情况下的对流换热特性进行了数值计算.计算结果表明,环形通道内、外壁加热热流密度比值的不同,对环形通道内、外壁与单相水的对流换热特性有着显著的影响.内、外壁面加热热流密度比值较小时,内壁的换热强于外壁的换热,随着内壁加热热流密度的增大,外壁的换热得到增强.但是,当内、外壁加热热流密度比值增加到一定程度时,外壁的对流换热特性将超过内壁的对流换热特性,与文献报道的实验结果一致.此外,环缝间隙的减小将导致环形通道的换热性能下降.

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.