Numerical Investigation of Laminar Flow and Heat Transfer in Rectangular Cross-Sectional Ducts

In this study, hydrodynamically and thermally developing laminar flow and heat transfer in a rectangular cross-sectional duct have been numerically investigated for steady state and constant surface temperature boundary condition. numerical solutions have been made for three different aspect ratios (α=0.25, 0.50 and 1.0) and in the reynolds numbers range of 600 to 2000. air (pr approximately equal to 0.72) is used as working fluid. a commercial cfd program ansys fluent 13.0 has been employed to carry out the numerical study. results are given in terms of nusselt number nu, darcy friction factor f, hydrodynamic lhd and thermal entrance lth lengths as a function of reynolds number re. also, velocity and temperature contours in the duct are given for different reynolds numbers. it is seen that the general equation given for circular ducts does not give a true hydrodynamic and thermal entrance length for rectangular ducts. the present results obtained from numerical study are correlated as a function of aspect ratio and reynolds number involving all aspect ratios and reynolds numbers used in this study.