Experimental research on bidirectional vortices in cold wall rocket thruster

The flowfield of bidirectional vortices in a cold wall rocket thruster was measured by two-dimensional PIV. Detailed flow structures were observed from tangential velocity images. Two parameters, injection velocity and length-to-diameter ratio of the thruster, were studied under different test conditions. Increasing the injection velocity greatly increased the tangential velocity, while increasing the length scale of thruster decreased the tangential velocity. The results also showed that flow dissipation is very small, implying vortices maintain their shape and intensity along thruster axis. Additionally, the axial velocity is very small in most regions except near the axis.