Overview on experimental techniques for heat flux and heat transfer estimations, during non-dropwise condensation.

Abstract

This review gives an overview of experimental techniques for the measurement and estimation of heat flux and heat transfer coefficients, during filmwise condensation. It is shown that heat flux can be estimated either from measurements in the solid medium, from boundary conditions, or from a global balance on the condensing fluid. Some advice is given in order to reduce measurement uncertainties. The choice of the measurement method does not depend on the value of the heat flux or heat transfer coefficient, but relies on experimental constraints, specific to each study (for example imposed subcooling of the solid medium). The heat transfer coefficient is then deduced from the heat flux and either from measurements or estimation of the wall and fluid temperatures, or from estimations of the secondary fluid heat transfer coefficient.