Experimental Investigation of Laminar Heat Transfer Inside Trapezoidal Duct Having Different Corner Angles

In this study, steady-state laminar forced flow and heat transfer in a horizontal smooth trapezoidal duct having different corner angles were experimentally investigated in the Reynolds number range from 10² to 10³. Flow is hydrodynamically fully developed and thermally developing under a uniform surface temperature condition. Based on the present experimental data of laminar flow in the thermal entrance region, new engineering correlations were presented for the heat transfer and friction coefficients for each corner angle. The results have shown that as the Reynolds number increases heat transfer coefficient increases but Darcy friction factor decreases. Also, it is observed that average Nusselt number increases while average Darcy friction factor decreases with increasing corner angle of the duct.