LAUSR

Burning tests were carried out for the 5-kN-thrust swirling-oxidizer-flow-type hybrid rocket engine to establish the engine technology and to obtain the fuel regression characteristics. The engine attained stable burning without any combustion oscillation and C* efficiencies of more than 98% under the 5-kN-thrust conditions. The maximum time-averaged thrust realized was 4.4 kN, which was lower than 5 kN. This was attributed to the regression rate being lower than the value estimated by regression rate correlation. The fuel regression behavior of this engine was characterized as the flow-development region near the grain leading edge and the fully developed turbulent flow region. The axial length of the flow-development region varied from that observed in the laboratory-scale engine, and it depended on the oxidizer mass flow rate, grain initial port diameter, and swirl strength. The controlling parameter of the regression rate in the fully developed flow region was modified to correlate with the grain port...