环形窄缝通道湍流流动换热特性分析

Analyses on Heat Transfer Characteristics of Single-Phase Turbulent Flow in Narrow Annular Channel

对双面加热环形窄缝通道内单相流动换热进行分析研究,提出了理论预测模型。基于该模型,对窄缝宽度分别为1.0、1.5、2.0 mm的环形通道单相湍流流动换热系数进行了理论计算,并与实验结果进行了对比,理论预测值与实验结果符合较好。研究表明:内外加热热流密度比对环形窄缝通道内的湍流流动换热过程有显著影响,在双面加热情况下,窄缝对流动换热过程强化与否,取决于内外管加热热流密度比及流动状态,即Re大小。

Heat transfer characteristics of single-phase turbulent flow in bilaterally heated narrow annular channels were studied and the theoretical model was proposed. Based on the present model, theoretical calculation was performed to predict the convective heat transfer characteristics for the developed turbulent flow in bilaterally heated narrow annular channels with gap sizes of 1.0, 1.5 and 2.0 mm, respectively. Calculations were found in good agreement with experimental data. The results show that the heat-flux ratios, i.e. the ratio of the heating flux of the inner tube to that of the outer tube, have great influences on the characteristics of heat transfer during single-phase turbulent flow in bilaterally heated narrow annular channels. Whether the convective heat transfer is enhanced or deteriorated with reduced gap in bilaterally heated narrow annular channels depends on the combination influence of the heat-flux ratio and the Reynolds number.