Studies on Heat Transfer in Laminar Free Convection with the Zehnder-Mach Interferometer

Abstract : Heat transfer in thermal free convection of air was investigated with the aid of a Zehnder-Mach interferometer on bodies with different shapes such as vertical plates; horizontal cylinders with circular and square cross-sections; arrangements of two and three horizontal cylinders; and an air-space enclosed between two horizontal concentric cylinders. All forms had in common that the convection flow set-up was two-dimensional. Free convection heat transfer has immediate application-possibilities for modern aircraft power plants for cooling and insulating problems connected with the handling of jet-engine fuels and rocket propellants. In the course of the studies, it was found that valuable information can be gained, by the interferometer method used, on turbulence. Data on thermal convection are useful also in understanding radial flow phenomena, which are caused by centrifugal forces in turbo-compressors and turbines. Data on heat transfer in turbulent-free convection will be presented at a later data.