After proposing a semi-analytical solution for swirl laminar flow, macroscopic characteristics of open-end pressure-swirl injector including discharge coefficient and spray cone angle are calculated. In the presence of air core of the axial region inside the injector, the laminar rotational flow equations are simplified, and with the assumption of the quasi-developed axial flow along the nozzle, the equations are iteratively solved employing separation of variables method. The accuracy of the proposed semi-analytical solution is compared by some numerical and experimental results on an open-end injector. The validity of quasi developed flow defined in the present work is confirmed based on the results of numerical simulations in different axial cross-sections. Moreover, findings demonstrate that the spray cone angle is predicted with an accuracy of about 3.7 for different operating conditions of experimental tests. The calculation of pressure distribution along the liquid film illustrates that viscous effect is negligible in pressure drop in the injector and the discharge coefficient is dominantly dependent on the flow inlet condition in the nozzle. Calculation of discharge coefficient presented in this paper shows an acceptable agreement with observations for different tests. Deviation of the theoretical discharge coefficient is less than 4.37 for various case studies with empirical results. (C) 2018 Elsevier Masson SAS. All rights reserved.
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