Visualization studies of the spray from swirl injectors under elevated ambient pressure

This paper presents the results of a visualization study on spray formed by swirl injectors with different geometries under elevated ambient pressure. A spray test facility with an ambient pressure chamber was constructed, and sprays were recorded using a high-speed camera. The parameters of the spray characteristics, e.g. the spray cone angle and breakup length of liquid sheet, were measured, and the effects of the ambient pressure and injector geometrical parameters on the spray were obtained. Experimental results indicated that when other parameters in the swirl injector remained constant, the increase of ambient pressure caused a decrease in the spray cone angle and the breakup length of liquid sheets. However, the mass flow rates remained nearly constant. An increase in nozzle diameter increased the spray cone angle, and the variation of breakup length according to nozzle diameter was somewhat irregular. The increase in the diameter of the tangential inlet reduced the spray cone angle; the breakup length scarcely varied.