Experimental investigation of forced convective heat transfer to air, liquids, and liquid mixtures in a long narrow channel

Abstract

This article presents data on forced convective heat transfer for fluids in a 11-m long rectangular (0.75 mm wide × 1.5 mm deep) serpentine-type mini-channel. The test section was fabricated by electro-discharge machining of a 2-mm thick stainless steel plate. The flow media experimented were air, ethanol, methanol, and their mixtures. Both laminar and turbulent flow regimes were covered in the case of liquids, but only turbulent regime was covered with air. The heat transfer coefficient is evaluated based on the heat carried away by the coolant and an average wall to mean fluid temperature difference. The Nusselt number is correlated through empirical correlations involving Reynolds number and Prandtl number, the hydraulic diameter being the length parameter.