A heat transfer correlation for condensation inside horizontal smooth tubes using the population balance approach

Abstract

Population balance model with homogeneous flow assumption is applied for forced convective condensation inside smooth horizontal tubes. The purpose of the paper is to examine the applicability of the homogeneous flow assumption for in-tube condensation although the common observation is that annular flow is physically more realistic [Soliman and Azer, ASHRAE Trans. 77(1), 210–224 (1971); Stoecker and DeGrush, Oak Ridge National Laboratory 81-7762/6 and 01 (1987); Taitel and Dukler, A.I.Ch.E.J. 22, 47–55 (1976)]. Lin's model [Lin, Ph.D. Dissertation (1979)] is applied suitably for the smooth tube conditions. Differences between Lin's model [Lin, Ph.D. Dissertation (1979)] and the present approach are clearly stated in the text. A correlation for the local heat transfer coefficient is obtained involving fewer parameters but with an additional constant and is applicable for oil-refrigerant mixtures also. Experimental data over a wide range of mass flux rates and condensing temperatures are used in obtaining the correlation. The predicted values of local Nu, compared with the experimental data indicate that 90% of the predictions are within ±20% of the experimental data, with a mean deviation of 13.2%.