Correction for Nusselt Number Correlations of Transcritical Methane Based on Radial Velocity Distribution

Abstract

This article conducts three-dimensional simulations for transcritical flow and heat transfer of methane in a rectangular channel under asymmetric heating conditions and compares the accuracy of three different Nusselt number correlations. A correction method for the Nusselt number correlation based on the secondary correction of the radial velocity distribution is proposed. The results show that by correcting the three correlations using the proposed method, the error of the average Nusselt number under the condition of heat transfer deterioration between the calculated values and the ones obtained from numerical simulations are reduced from 88.26%, 11.41%, 19.29% to 13.71%, 0.47%, and 6.02%, respectively. Compared with the correlation obtained by directly modifying based on the heat transfer deterioration condition data, the Nusselt number correlations modified by the proposed method achieve higher accuracy, and the calculation error are limited to within 15%. Overall, the modified Bishop correlation has the highest calculation accuracy among the three correlations, and the errors between the calculated values and those obtained from numerical simulations are limited within 6% under different mass flow rates.