The discharge coefficient of effervescent atomizers

The paper contains the results of experimental investigation of air–water atomization process in effervescent nozzles with internal mixing. The aim of study was analysis of pressure drop and discharge coefficient. The study was carried out at liquid flow rates changed from 0.0014 to 0.011 [kg/s] and gas flow rates from 0.00015 to 0.0065 [kg/s]. It corresponded to gas to liquid mass ratio (GLR) values from 0.014 to 0.46. The experimental results show that CD is a non-linear function of GLR. Their values are decreasing rapidly as GLR is increased from zero to around 0.07 and thereafter decreasing at a slower rate with further increase in GLR. The two regimes were observed. The first regime is characteristic for bubbly flow. The second is typical of annular flow regime. Boundary between bubbly and annular flow regime is observed at GLR = 0.07 for investigated systems. The experimental results show that CD is a function of GLR(d/D) and give the common correlation for all geometries studied. The correlations for CD as a function of GLR(d/D) are proposed.