On Various Forms of the Heat and Mass Transfer Analogy: Discussion and Application to Condensation Experiments

The paper is focused on some of the different forms of the analogy between heat and mass transfer, as they appear in available textbooks and literature on condensation and evaporation. The motivation for the work is the need to clearly point out the assumptions at the basis of each one of them and to quantify the related differences in the application to real experimental data. In fact, the analogy is very often cast in apparently very different forms, whose relation to each other must be carefully understood when a selection among them is performed for a given application. Basing on previous experience in the analysis of heat and mass transfer for passive cooling in light water nuclear reactors, the present work briefly summarises the theoretical bases of the selected forms of the analogy, comparing the related relationships. Then, an experimental activity related to condensation on a flat plate in the presence of noncondensable gases, aimed at providing data for nuclear reactor containment analysis, is presented and the obtained results are processed by the different forms of the analogy to assess the related quantitative differences, thus providing a clearer perspective about the results of their use in engineering applications.