On the Thermal Interaction Between an Isothermal Cylinder and Its Isothermal Enclosure for Cylinder Rayleigh Numbers of Order 104

Abstract

An experimental investigation is made of the thermal interaction between a horizontal isothermal cylinder centrally located in a water-cooled isothermal cubical enclosure. The study is restricted to laminar flow and cylinder Rayleigh numbers of order 104. The application of interest is the cooling of electronic systems. This field is currently lacking in techniques that can measure the complex fluid phenomena encountered in real systems. The paper therefore begins with an experimental review of interferometry to assess its applicability as a potential solution to this need. Based on this review, a real time Digital Moire´ Subtraction interferometer is used to measure temperature profiles, and local Nusselt number distributions in two regions of interest: the plume impingement on the ceiling of the enclosure, and the upper corner region of the enclosure. A Mach-Zehnder interferometer is used for the cylinder Nusselt number distribution. Results are compared both qualitatively and quantitatively with a numerical simulation run on a commercial CFD package widely used for electronic system temperature predictions. The paper gives considerable insight into the nature of the enclosure heat transfer and an indication of the accuracy of a widely used predictive code.