Thermal and hydraulic analysis of a rectangular microchannel with gallium-copper oxide nano-suspension

In this work, the utilization of liquid metal nano-suspension in a rectangular microchannel was experimentally investigated with the view to develop a new insight for the fabrication of solar thermal receiver working with liquid metals. Gallium with superior heat transfer behavior was selected as a working fluid and copper oxide was dispersed in it at weight fractions of 5%, 10% and 15%. Effects of various operating parameters including applied heat flux to the microchannel, the concentration of nanoparticles and flow rate of nano-suspension on the heat transfer coefficient, pressure drop and thermo-hydraulic performance of the system were evaluated. Results showed that gallium-based nano-suspensions offer a potential for cooling a high heat flux microchannel surface. The highest thermal performance of ~3.3 was achieved in a laminar regime and at wt% = 10. Heat flux and flow rate were found to plausibly enhance the heat transfer coefficient, however, for the mass concentration, the thermo-hydraulic performance was decreased at wt% = 15, due to the augmentation of viscosity. Also, it was found that agglomeration and clogging are other reasons for the augmentation of the pressure drop within the microchannel.