Internal flow and discharge coefficient characteristics of oil jet nozzles with different orifice angles under non-cavitating conditions

Abstract The orifice angle has great impact on the internal flow and discharge coefficient characteristics of oil jet nozzles. This paper presents numerical research on the internal flow and discharge coefficient behaviors of oil jet nozzles with different orifice angles. For this purpose, oil jet nozzles with different orifice angles in the range from 0 ∘ to 90 ∘ were evaluated under real injection pressure difference conditions ( 0.10 ∼ 0.50 MPa). The main results show that the mass flow rate, discharge coefficient and velocity coefficient decrease first and then increase with the increasing orifice angle. The value of each parameter corresponding to the orifice angle of 90 ∘ is slightly higher than that of 0 ∘ . The minimum value is obtained with the orifice angle of 30 ∘ , and the relative deviation between the highest and the lowest mass flow rate exceeds 11.5%. On this basis, the prediction formula of angle coefficient with extremely high goodness of fit is obtained by using polynomial fitting method for the multiple groups of normalized discharge coefficients, and the corrected empirical correlation of discharge coefficient and mass flow rate are developed in the light of the angle coefficient. Comparing the corrected empirical correlation prediction results with the numerical simulation results, the maximum deviation of the mass flow rate is 1.9%.