Numerical and experimental studies on laminar hydrodynamic and thermal characteristics in fractal-like microchannel networks. Part B: Investigations on the performances of pressure drop and heat transfer

In the present paper, the numerical simulations and experiments were carried out to explore the laminar hydrodynamic and thermal characteristics in the symmetrical fractal-like microchannel networks, and the pressure drop and heat transfer for the networks were compared with those for the S-shape and straight microchannels. To evaluate the comprehensive performances of the microchannels used in this study, the coefficients of performance were introduced based on two criteria. The influences of geometrical parameters of aspect ratio, branching level, and bend type on the behaviors of flow and heat transfer were investigated in detail. The studies showed that parameters of both aspect ratio and branching level had substantial effects on the pressure drop and heat transfer. In addition, the bends with fillets in the microchannels were verified to reduce the local pressure loss compared with those having 90° bends. However, the fillet had little contribution to the heat transfer. It was concluded that a microchannel network with a smaller aspect ratio, a higher branching level, and a fillet bend would achieve a higher performance associated with pressure drop and heat transfer.