Effect of fabrication parameters on capillary performance of composite wicks for two-phase heat transfer devices

Advanced thermal management solutions for various applications have promoted the development of composite wicks for two-phase heat transfer devices (TPHTDs). In this study, a number of composite wicks by covering a layer of sintered copper powder on micro V-grooves were developed. A ploughing-extrusion (P-E) method, as a material-saving fabrication means, was utilized to process the micro V-grooves on copper plate as the base of composite wicks. Using an infrared (IR) thermal imaging method, the capillary rate-of-rise tests with ethanol and acetone were carried out to characterize the capillary performance, which integrates both capillary pressure and permeability. The effects of fabrication parameters, including groove depth and pitch, sintering temperature and time, on the capillary performance of composite wicks were focused on and examined for the purpose of design optimization. Test results show that there is an optimal groove geometry with the groove depth of 0.85 mm and pitch of 0.45 mm to achieve the maximum capillary performance, and sintering processes of 950 °C along with 30 min should be chosen. Both working liquid test results exhibit fairly good agreement and demonstrate that the IR thermal imaging provides an accurate means to evaluate the hydraulic properties of composite wicks.