Application of a New Analogy for Predicting Heat Transfer to Cross Rod Bundle Heat Exchanger Surfaces

Abstract

A new technique for prediction and measurement of compact heat exchanger surfaces has been established. The method utilizes an analogy between heat transfer and fluid friction proposed by a French scientist in 1928. The applicability of this analogy to plate heat exchanger surfaces was examined recently. The present work proposes to use the same analogy for crossed rod bundles used in regenerators. For this purpose, the analogy equation has been modified to include a geometric factor which takes care of the fraction of the pressure drop arising out of skin friction. The proposed form of equation is found to be more general, applicable to crossed rod structures of any geometric configuration. The proposition was formulated based on standard data from the literature and also by conducting independent experiments. The result of the transient experiment indicate excellent adherence to the proposed analogical equation. The experimental evidence clearly indicates the possibility of predicting heat transfer characteristics of such compact surfaces by measuring pressure drop alone across the packed bed formed by the surface under consideration.