The effect of tangential gas velocity on combustion instability in a liquid-gas combustor

Abstract

A small, uncooled liquid rocket motor was utilized to examine the effects of the magnitude and direction of a steady vortex velocity on combustion instability. The rocket operated on normal heptane and air, with air flow rates controllable to allow for various amounts of tangential momentum. Results of the investigation indicated that an energy feedback mechanism, through tangential momentum, did exist for both tangential and radial modes of instability. It was further shown that limit values of tangential velocity did exist, for a particular combustor, above and below which instability did not occur.