3-D numerical simulations of flow loss in helical channel

The flow loss of a helical channel Magnetohydrodynamic (MHD) thruster without MHD effect was numerically studied with 3-D simulations, and a flow loss coefficient ζ was defined to quantify the flow loss and its influencing factors were studied. The results show that ζ decreases in a first-order exponential manner with the pitch of a helical wall and the Reynolds number, and it declines slowly when t/T > 0.2 and Re > 105, a flow guide makes the flow more smooth and uniform, especially in the flow guide and helical wall sub-regions and thus reduces the flow loss greatly, by about 30% with the averaged value of ζ from 0.0385 to 0.027, a rectifier weakens the helical flow and strengthens the axial one in the rectifier and outlet sub-regions, thus reduces the rotational kinetic pressure with the averaged value of ζ declining about 4% from 0.0385 to 0.037, and ζ decreases with a rectifier's axial length when Re > 105.