A numerical and experimental investigation of flow and heat transfer over elliptic tube arrays with compact configuration

A 2D numerical investigation is presented to examine the mechanism of the field synergy theory how to control convection heat transfer when-airs flow across the oval tube arrays. The calculated results indicate the field synergy of elliptic tube array is worse than the circular one with the same-perimeter at the same Reynolds number, but is better than circular one at the same pressure drop. An experimental study of heat transfer performance for three elliptic tube arrays with compact configuration is also presented in this study. For comparison purpose, four staggered oval tube arrays with different-axis ratio are tested to examine their heat transfer performance when they have the same perimeters, but other geometry parameters keep constant. The relation between Nusselt number and friction coefficients vs. Reynolds number is gained for three axis ratios. According to Deng's performance evaluation criteria, efficiency indexes of the three elliptic tube arrays are obtained at the same fan power comparing with circular one. The axis ratio 2.8:1 is the best one