S-ST-1-11 Evaluation of Laminar Heat Transfer Methods for Horizontal Tubes
The performance of the HTRI laminar heat transfer methods for horizontal tubes was evaluated relative to 219 heating and cooling data points for four different fluids. Results of this study show that, in general, the HTRI overall method overpredicted the heating data by 13 percent and underpredicted the cooling data by 1 percent. The HTRI local method, which is a modified version of the overall method as used in HTRI Xchanger Suite®, overpredicted both the heating and cooling data by an average of 30 percent and 14 percent, respectively. In addition, the local method predicted heat transfer coefficients that were consistently 16 percent higher than the overall method. These findings suggest that Xchanger Suite may overpredict tubeside heat transfer coefficients, which could result in undersized heat exchangers. Four literature correlations were also evaluated; one predicted heating data and a second predicted cooling data more accurately than the HTRI methods.