Effect of geometric parameters on spray characteristics of pressure swirl atomizers

Experimental study on the effects of the geometric ratios of pressure swirl atomizers on the spray characteristics such as spray cone angle and SMD has been conducted. Twelve atomizers of different geometric configurations have been used for this purpose. The atomizers have been divided into three groups, each containing four nozzles, based on the variation in three geometric ratios i.e. Ds/Do, Lo/Do and Ls/Ds.These ratios have been varied from 3 to 7.5, 0.81 to 2.69 and 1.25 to 5.0 respectively for the examination of their influence on the spray cone angle and SMD. Spray cone angle was measured through high speed camera while SMD was measured by using Malvern instruments. The experiments were performed at two injection pressures of 0.8 MPa and 1.2 MPa by using water as the test liquid. The results show that the spray cone angle continuously decreases with the increase in ratio Ds/Do, however, an optimal value 3.75 of this ratio has been recognized during the measurements of SMD. Furthermore, SMD has been observed to continuously increase with the increase in Lo/Do, while an optimal value 1.44 of this ratio has been identified during the measurements of spray cone angle. Similarly, an optimal value 3.75 of the ratio Ls/Ds has also been determined from the experimental measurements of spray cone angles and SMD.