Experimental Investigations on Fluid Flow and Heat Transfer Through Rectangular Mini Channels Available to Purchase

Experimental investigation aimed at characterizing fluid flow and heat transfer in mini channels is presented in this paper. Forced convection flow of water through rectangular mini channels with hydraulic diameters in the range 0.28–3.67 mm and aspect ratio (H/W) 0.33–2.5 was investigated, for different flow regimes, and correlations were proposed for the flow friction and heat transfer characteristics. Fully turbulent convective heat transfer was achieved in mini channels at lower Reynolds numbers compared to conventional sized channels. Critical Reynolds number for flow transition was found to decrease with the hydraulic diameter. A comparison of the results in mini channels and microchannels indicate common trends, especially in the dependence of flow transition on the hydraulic diameter. Experimental results were compared with predictions for flow and convective heat transfer in conventional sized channels. Based on the finding that the frictional and heat transfer characteristics of the mini channels deviated from the predictions, a few new correlations are proposed for the laminar and turbulent flow regimes.