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为了发展适于螺旋管内流动沸腾传热系数关联式,基于流动沸腾传热机理,引入参数Dn数来修正复杂管道对传热系数的影响,并经过回归计算确定Dn数的指数,从而发展了螺旋管内流动沸腾传热系数关联式。进一步分析了传热系数预测值与实验值的偏差随流量、干度的变化情况。利用以R134a为介质的螺旋管传热实验数据验证了该关联式的适用性,并采用平均相对误差(the mean relative error,MRE)和均方根误差(the root mean square error,RMSE)来衡量预测结果的准确性,计算出MRE在8.23%范围内,RMSE为0.532。该平均相对误差值和均方根误差值都比较小,表明回归计算结果符合要求。因此,复杂管道引入参数Dn数建立传热系数关联式是非常适用的,并值得推广应用。
In order to develop a correlation formula suitable for the flow boiling heat transfer coefficient in a spiral tube, a Dn number is introduced to correct the influence of the complex pipe on the heat transfer coefficient, and the index of the Dn number is determined through regression to develop the spiral Tube boiling heat transfer coefficient correlation. Further analysis of the heat transfer coefficient prediction and the deviation of the experimental value with the flow rate, dryness changes. The applicability of this correlation was verified by experimental data of spiral tube heat transfer with R134a as a measure of the mean relative error (MRE) and the root mean square error (RMSE) Predict the accuracy of the results, calculated MRE 8.23% in the range, RMSE 0.532. The average relative error and root mean square error are relatively small, indicating that the regression results meet the requirements. Therefore, it is very suitable to establish the correlation coefficient of heat transfer coefficient by introducing the number of Dn into the complex pipeline, and it is worth to be popularized and applied.