制造了一台直通道及半圆形截面的印刷电路板式换热器(PCHE)样机并进行了不同流量下的水-水过渡区下的传热与流动实验.采用经典宏观圆管传热与流动关联式获得的计算结果与实验结果有明显偏差,具体为实验f因子更大,总体传热系数随雷诺数的变化更复杂.因此,对相应应用范围内PCHE过渡区液体流动的传热与流动关联式进行了校准.为了获得传热关联式,利用数值模拟获得PCHE过渡区单侧平均表面传热系数.结果表明,基于平均表面传热系数获得的总体传热系数与实验值平均偏差为8.5%,最大偏差为17.2%,但基于平均表面传热系数获得的总体传热系数预测模型与实验结果的偏差在10%以内,说明通过数值模拟获得PCHE过渡区单侧平均表面传热系数是一种可行的思路.
A Printed Circuit Heat Exchanger(PCHE),with straight channels and semi-circle cross section,was fabricated and experimental studies on heat transfer and fluid flow were conducted,during which the flow regime was transition flow,water was working fluid,and flow rate of water was various.The results obtained from correlations of macro circular tubes had obvious deviations from the experimental results.Specifically,the f factor obtained from experiments are larger,and the changes of the overall heat transfer coefficient were more complex with various Reynolds number.The heat transfer and flow correlations in transition zone of PCHE was calibrated within corresponding application ranges.In order to obtain the heat transfer correlations,a numerical method was introduced to obtain one-sided average convective heat transfer coefficients under transition flow.The results showed that the average deviations of the overall heat transfer coefficient obtained from average convective heat transfer coefficients was 8.5%comparing to experimental results,while the maximum deviation reached 17.2%.However,in spite of that,a correlation to predicted the overall heat transfer coefficients through average convective ones still can be obtained,and the deviations comparing with experimental results was within 10%.It is recommended that obtaining one-sided average convective heat transfer coefficient with numerical method is feasible especially when it was transition flow in PCHE.