To examine the fluid flow and heat transfer characteristics in a microchannel with fan-shaped reentrant cavities,the numerical investigations were conducted,and the results were compared with the conventional rectangular microchannel data.The SIMPLEX method was used for the computation.The effects of volumetric flow rate,heat flux on the pressure drop and thermal resistance were investigated in detail.The numerical simulation results indicate that a microchannel with fan-shaped reentrant cavities can improve heat transfer performance with an acceptable pressure drop when the Reynolds numbers are larger,and the fluid flow and heat transfer mechanism can be attributed to the interaction of the redeveloping of hydraulic and thermal boundary layers,the effect of jet and throttling and the stagnation zone of laminar flow.