分离式热管小倾角蒸发段传热特性的试验研究

由于分离式热管蒸发段水平及小倾角布置的重要工程应用意义,在试验台上进行了1∶1的模型试验,对分离式热管蒸发段的传热特性进行了试验研究.试验确定了工作温度、热流密度、充液率、倾角等因素对传热特性的影响;用核态沸腾理论对蒸发管的换热特性进行了无因次分析,回归试验数据得到了无因次对流换热准则关系式,它与试验结果有很好的一致性,相对误差在15%以内.研究结果表明,随着热流密度的增加,换热系数增加;工作温度增大,换热系数也增大;倾角增加时,换热系数增大;合理充液率为65%~90%,在此范围内,充液率对换热系数的影响很小.此研究结果为大型小倾角布置的分离式热管换热器的工程设计提供了依据.

Experimental study on the performances of the heat transfer of the small dip-angle evaporation segment of a separate-type heat pipe

The horizontal and small dip-angle arrangement of the evaporation segment of a separate-type heat pipe is of important engineering significance.For this reason,an experimental study on the heat transfer characteristics of it is carried out on a model with a scale of 1∶1.The effects of working temperature, heat flux,working fluid inventory and dip-angle on its heat transfer performances are determined.The dimensionless analysis of the convection heat transfer coefficient of the evaporator is made by means of nucleate boiling theory,and the dimensionless correlation of convection heat transfer coefficient is obtained by the regression of experimental data.The relative errors between the results calculated according to the regression correlation and the experimental data are less than 15%.It is shown that the convection heat transfer coefficient increases with the increases of working temperature,heat flux and dip-angle.The optimum working fluid inventory is in the range of 65%～90%,and working fluid inventory has little effect on the convection heat transfer coefficient in the range. The results in the paper may provide the basis for the engineering design of large-scale small dip-angle heat exchangers of separate-type heat pipe.