APPLYING INTERFEROMETRY IN RESEARCHING CONVECTION HEAT TRANSFER FROM PANEL RADIATORS

摘要

This article is concerned with interferometric research into temperature fields and heat transfer via laminar natural convection of a reduced model of panel radiators with the help of a Mach-Zehnder interferometer. Heat transfer is determined by the temperature derivative at the surface of the radiator walls evaluated by means of an interferometrically measured temperature field. This article deals with problems involved in applying the results of the measurement to an actual radiator and problems in determining the temperature derivative at higher wall surface temperatures, necessary to simulate heat transfer in an actual radiator. High surface temperatures complicate the evaluation of interferograms. A method for evaluating the temperature derivative in the case of higher wall temperatures is worked out in the article, based upon measuring the thickness of thermal boundary layers. The interferograms acquired are evaluated by a computer with the use of specially developed software. The outcome of the research consists in relationships for the calculation of Nusselt numbers across the face of the panel radiator as well as in the slots between the walls of double or triple panel radiators and suggestions for the optimal configuration of panel radiators to ensure maximal heat output.