Numerical prediction of air core diameter, coefficient of discharge and spray cone angle of a swirl spray pressure nozzle

Theoretical predictions of air core diameter, coefficient of discharge and spray cone angle of a swirl spray pressure nozzle have been made from numerical computations of flow within the nozzle. The diameter of central air core that stabilizes inside the nozzle has been predicted from a hydrodynamic situation that yields the minimum resistance to the liquid flow in the nozzle at given operating conditions. The coefficient of discharge and spray cone angle have been evaluated from the distributions of the different velocity components of liquid flow at the nozzle orifice. It has been observed that the coefficient of discharge Ca decreases, while the air core diameter d(a) and spray cone angle psi increase with the increase in nozzle flow in its lower range. However, all these parameters C-d, d(a) and psi finally become independent of nozzle flow. Predicted values of d(a), C-d and psi for different geometrical dimensions of the nozzle have been compared with the empirical data available in the literature. (C) 2000 Elsevier Science Inc. All rights reserved.