Numerical investigation of supercritical methane in helically coiled tube on regenerative cooling of liquid rocket electromechanical actuator

A numerical model employing the SST k-ω turbulent model is built to predict the turbulent flow and heat transfer of supercritical methane in helically coiled tube for the heat dissipation of high-power electromechanical actuator. The heat transfer mechanism and the crucial influence factors viz. pressure and heat flux are discussed, and the comparison between the semi-empirical heat transfer correlations and the simulation results are performed. The calculation results indicate that: (1) before the pseudo-critical point of supercritical methane in helically tube, the effect of the buoyancy caused by the thermophysical properties cannot be neglected; (2) the domination of the centrifugal force on the heat transfer after the pseudo-critical point of supercritical methane can be confirmed obviously, contributed to the non-uniform distribution of flow and heat transfer coefficient in cross sections; (3) pressure and heat flux both exhibit significant effects on heat transfer of supercritical methane in helically coiled tube; (4) the semi-empirical heat transfer correlation from Zhang et al. shows the best agreement against the simulation result in the present paper.