An experimental study on velocity and temperature of Al/water microfluid in a circular tube with swirl

Abstract

The present study is focused on the application of a tangential slot swirl generator to improve heat transfer in a horizontal circular copper tube. Convective heat transfer in internal flow with high specific surface area, increasing heat transfer coefficient, swirling flow, and improved transport properties have been studied in previous decades. Al particles (measuring about 100-130 mu m) were employed. Particle image velocimetry was utilized to measure velocities with different Reynolds numbers along the test tube with and without swirl flow. A copper tube with a resistance of 9 Omega/m was uniformly heated by winding a heating coil for heat transfer. Experiments involving Al particles are performed with the Reynolds number ranging from 6,800 to 12,100 with and without swirls. Experimental data on the Reynolds number obtained along the test tube with and without swirl were presented for comparison with the Nusselt number and the Dittus-Boelter equation. The Nusselt number improved with the increase in the Reynolds numbers or swirl intensity along the test tube