Numerical research on entrance effect on internal flow characteristics in micro-scale

Entrance effect, which is a key factor that affects the flow and heat transfer characteristics in microchannels, has been studied in details numerically. Some strange phenomena were found, such as the maximum velocity occurs not in the channel core but near the walls due to the surface effect, et al. The effects of Reynolds number, hydrodynamic diameter and height-to-width ratio on hydrodynamic entry length are analysed. The correlation of entrance length, which is useful for designing and optimising the microchannel heat sinks and other microfluidic devices, is established.