Heat Transfer and Pressure Drop Characteristics of a Dimpled Flat Tube

The fully developed turbulent momentum and heat transfer induced by three-dimensional roughness elements on the inner wall surface in a dimpled tube is studied analytically based on standard k- ε turbulence model with a Navier-Stokes equation solver. Experimental investigations are also carried out to obtain pressure drop characteristics and to verify the numerical results of the fluid flow. The calculated pressure fields exactly predict the friction factor relation obtained from experiment at high Reynolds number cases, Re_D > 4,000. The complex velocity distribution taken from analysis also reasonably well agree with experiment. For the range of present Reynolds number, 2,000 < Re_D < 10,000, the numerical analysis demonstrates that the heat transfer enhancement decreases with increasing Reynolds number.