Structures of Angled Aerated-Liquid Jets in March 1.94 Supersonic Cross flow

The structures of aerated-liquid jets injected into a supersonic crossflow have been studied experimentally. Aerated-liquid injectors with diameters of 0.020 , 0.040 and 0.060 were flush mounted on the bottom plate of a supersonic wind tunnel to provide normal and angled injection. Free stream Mach number and temperature were held constant at 1.94 and 500°F, respectively. Water at room temperature was used as the liquid injectant and nitrogen gas used as the aerating gas. Wide ranges of test conditions for injection angle (θ), injector orifice diameter (d0), jet-to-air momentum flux ratios (q0), and gas-to-liquid ratios (GLR), were studied. Injection angles were varied from 45 downstream to 90 (normal to freestream). Jet-to-air momentum flux was varied from 1% to 15% of the free stream and gas-to-liquid ratios from 0% (pure-liquid injection) to 10%. Shadowgraph and laser sheet illumination techniques were used for spray visualization while a phase Doppler Particle Analyzer (PDPA) was utilized to quantitatively measure droplet and spray plume properties. The data from all three methods were used to develop correlations for the droplet and spray plume properties for aerated-liquid jets using a linear fit of the base-10 logarithm coefficients. Correlations relating penetration height and spray plume width of the injected spray to the above listed parameters, as well as the normalized axial distance downstream of the injector, x/d0, were formulated based on all three measurement techniques. Results indicate that a reasonable prediction of penetration height, spray plume cross sectional area, and local equivalence ratio can be obtained from PDPA data, while other visualization techniques tend to under-predict such quantities