A CRITICAL-REVIEW OF CORRELATIONS FOR CONVECTIVE VAPORIZATION IN TUBES AND TUBE BANKS

Three types of phenomenological models are used for calculating heat transfer coefficients in convective vaporization-the superposition, asymptotic, and enhancement models. These models were originally proposed for in-tube vaporization. The objective of the present study is to critically assess these models, and to establish a rational basis for a modified model. Saturated convective vaporization is of key interest in this review. Much more work has been done on in-tube flow than for tube banks. This article surveys the currently available models, and establishes the commonality and differences of the correlations. Separate emphasis is given for tube bank correlations. The correlations for tube banks are compared to those used for in-tube flow. We show that the current correlations may be grouped into three basic types-superposition, enhancement, and asymptotic models. Each type is discussed in order to address the concepts involved in them. Problems associated with certain published models are discussed. The foundations of a rationally based model should be equally applicable to in-tube flow and tube banks. An "asymptotic" model is suggested for application to tubes and tube banks.