Experimental Study of Forced Convection Heat Transfer of Water in a Short Micro Duct at Turbulent Reynolds Number

The present study deals with experimental investigation of cooling of machining tools, by water flowing through a microduct at the tip of the tool. The microduct is of diameter of around 200μm and the flow takes place at turbulent Reynolds number. The outer wall temperature of microduct and the temperature of water at inlet and exit have been measured. The convective heat transfer coefficient is calculated at different wall temperatures and varying liquid mass flux. The experimental results shows that the average Nusselt numbers for the short micro-duct are higher than those predicted by conventional correlations for large diameter ducts. A correlation has been proposed to compute convective heat transfer during turbulent flow through a short microduct of a particular geometry for a range of Reynolds and Prandtl numbers.