Oscillatory combustion of a liquid-oxygen jet with gaseous hydrogen

Abstract

Time variations in combustion parameters are measured in a zone of oscillatory combustion to aid in formulating a model of the oscillatory-combustion process.The study centers on a single 0.028-inch-diameter liquid-oxygen jet reacting with diffusely injected gaseous hydrogen in a two-dimensional circular combustor.Instability is coupled with the first spinning transverse mode.approaching that of a plane traveling wave.Gas velocities agree with calculated values for an isentropic wave process using experimentally determined gas properties.Photographs of the liquid jet correlated with phase position in the wave show the response of the jet to its changing environment.Mass removal from the jet is continuous but varies with time and is in the form of unresolved small drops or vapor.It appears to lag behind the pressure and velocity change.Mean jet length agrees with that predicted for steady transverse gas velocities.Radiation surveys indicate energy release at and beyond the position of mass release from the jet.The distributed radiation pattern may be attributed to gas-phase mixing processes.Time variations in gas radiation are basically in phase with pressure and primarily correspond to an isentropic process for a gas composition in thermodynamic equilibrium.Cyclic reaction beyond this in-phase and concentration-dependent behavior is indicated by a skewing of the radiation wave shape in the direction of increasing time.A portion of the energy released appears to lag behind the pressure change.A conceptual model of instability based on the observed parameter variation is presented.Energy addition to the wave is dependent on the mass released from the jet, gas mixing, and a concentration-dependent reaction process.The effect of mass release is amplified by a steady gas flow.A correlation of pressure and gas velocity shows a predominantly in-phase relation