Investigation of injectant properties on jet penetration in a supersonic stream

The effect of liquid properties on secondary injection from a single small-diameter nozzle in a supersonic stream was investigated experimentally. Normal penetration of liquid jets was inferred from scattered-light and schlieren photographs. Primary flows of Mro = 2.8 and 4.0 were produced in a 4 X 4-in. blowdown wind tunnel. Data on normal penetration of roomtemperature water were used to extend published correlations to lower injection pressure ratios. The effect of vapor pressure on penetration was investigated by injecting superheated water and acetone. Penetration height was correlated with injection pressure ratio for superheated liquid injection; these data were compared with roomtemperature results. Vapor pressure breakup outside of the spray nozzle had little effect on the penetration height. Liquid viscosity and surface tension were varied over a wide range of conditions; neither property affected the penetration height for flow in the acceleration-wave breakup regime.