Study of penetration of a liquid injectant into a supersonic flow

Abstract

A study of normal and lateral spray penetration for small-diameter, high-pressure, liquid jets issuing at an angle to a uniform supersonic stream is reported. The experimental program was carried out in the 4-in. by 4-in. blowdown supersonic wind tunnel of the Naval Postgraduate School in Monterey. The flowfield is observed by means of a schlieren system, and the spray distribution is indicated by the light scattered by the liquid droplets. Data on normal penetration, in good agreement with data inferred front other investigations, indicate that a single-parameter correlation exists between the properly nondimensionalized penetration height and the injection pressure ratio. Injecting the coolant at a forward angle to the flow produces no substantial change in the penetration height. The data on lateral penetration show the spray width behind the jet to the proportional to the jet diameter with only a weak dependence on the injection pressure ratio. Analytical nodels proposed by previous investigators are critically examined in the light of our results. No single model predicts a proper scaling law for both normal and lateral penetration.