Single-phase flow and heat transfer in swirl microchannels

Flow and heat transfer characteristics of swirl microchannels of differing rectangular cross sections have been experimentally investigated using ethylene glycol solutions of 30% (volume concentration). Ten test sections with hydraulic diameters from 0.3 to 0.8 mm are tested. The influence of geometry and fluid velocity on the behavior of flow and heat transfer through these swirl microchannels is reported. Flow and heat transfer correlations for these swirl microchannels are obtained. Friction factors and average Nusselt numbers are determined and are compared with conventional curved duct correlations. The result indicates that values for the friction factors and average Nusselt numbers obtained using conventional correlations provide poor estimates. Flow and heat transfer behaviors are compared with straight microchannels, and the results indicate that swirl microchannels improve heat transfer performance by 50% on average.