Thermal performance investigation of supercritical methane in minichannel heat sink on flight vehicle actuator under geometry effect of cross section

With rapid development of high-power electromechanical actuator, the conventional cooling technologies become hard to meet the requirement of heat dissipation, the minichannel heat sink using supercritical cryogenic propellant methane is proposed for high power electromechanical actuator's thermal control in flight vehicles, withstanding the extreme ambient of flight vehicles like gravity acceleration and replacing the air-cooled method under the rarefied atmosphere. However, the optimal working patterns especially considering both the factors of geometric and operation conditions need to be investigated thoroughly due to the complicated heat transfer mechanism of supercritical methane in minichannel of heat sink. Therefore, in the present article, based on the actual configuration of IGBT power module in flight vehicle actuator, the numerical models of minichannel heat sink under various cross sections with the same aspect ratio and hydraulic diameter, namely triangle, trapezoid, and rectangle, are established with the overall region of 50 mm x 100mm. The hydraulic diameter of fluid region in single channel is 1.5 mm, the size of solid region for computational domain is 3 mm x 5 mm (width x height) and the material is silicon. The overall channel number is 17, the inlet Reynolds number covers from 500 to 1500 and the operation pressure ranges 5 MPa to 7 MPa, while the ratio of mass flux to heat flux keeps constant. On this basis, the thermal performance, in especial the local heat transfer features of supercritical methane in minichannel heat sinks under three different geometric configurations of cross section is researched.