Experiments were carried out to investigate the flow and heat transfer characteristics of water/ethanol mixtures through five kinds of silicon microchannels with different geometrical parameters.The experimental correlations of flow friction and heat transfer were obtained.The effect of the geometrical parameters on the flow and heat transfer characteristics in silicon microchannels was remarkable.The friction factors of water/ethanol mixtures were the same as those of pure water

but the Nusselt numbers were different.It was also found that the entrance effect was notable for both flow and heat transfer in microchannels.