FRICTION FACTOR AND NUSSELT NUMBER IN FLAT TUBES WITH ROUNDED EDGES

This paper is aimed at presenting a fluid flow and heat transfer analy sis in flat rectangular ducts with rounded edges. The differential mom entum and energy equations are numerically solved by a finite differen ce technique for a fluid in steady-state, laminar flow with constant w all temperatures. The two-dimensional (2-D) velocity and temperature p rofiles are so determined, and the friction factors and the Nusselt nu mbers are predicted for different aspect ratios (O less than or equal to alpha less than or equal to 0.5) for Newtonian and slug flows. The results show that the differences in friction factor and Nusselt numbe r between round-edged ducts and rectangular ducts increase when the as pect ratio increases. Very accurate results are predicted by simple po lynomial expressions.