Heat transfer coefficients in horizontal multi-tubular evaporators

Abstract

Various correlations available in literature for predicting two‐phase heat transfer coefficient in annular flow regime are reviewed. Accurate prediction of these coefficients effect not merely the efficient and economic design of equipment but also its safety in operation. Instabilities can result in boiling crises, disturb the control systems and cause mechanical damage. It is observed that applicability of these correlations for a multi‐tubular heat exchanger has not been investigated. Experimental studies on a heat pump assisted distillation unit have been conducted. Results show that the actual values of heat transfer coefficients are consistently higher than those predicted by Shah, Pierre and Guerrier's correlations.