Yousefi - Assistant Professor, Razi University
Ashjaee - Associate Professor, University of Tehran
Paknezhad - Assistant Professor, Razi University

Natural convection heat transfer from the vertical array of five horizontal isothermal elliptic cylinders with vertical major axis which confined between two adiabatic walls has been studied experimentally. Experiments were carried out using Mach-Zehnder interferometer. The Rayleigh number based on cylinder major axis was in the range between 103 and 2.5×103 . The effect of wall spacing and Rayleigh number on the heat transfer from the individual cylinder and the array were investigated. Heat transfer correlation has been developed for the array. A relation has been derived for optimum wall spacing at which the Nusselt number of the array attains its maximum value. At optimum wall spacing, approximately15% increase in the heat transfer from the confined array of elliptic cylinders has been observed with respect to unconfined case. Also a heat transfer correlation has been proposed for a single elliptic cylinder with vertical major axis and it has been compared with earlier works.

Mach-Zehnder، Interferometry، Natural Convection، Elliptic Cylinder، Vertical Array