Finite element analysis on the hydraulic load in nozzle of marine diesel engine and its structure improvement

Three-dimension calculation model of flow in the nozzle of a certain diesel engine is set up. Simulation of fluid flow in the nozzle is performed by computational fluid dynamics software package ANSYS FLOTRAN. Pressure distribution in the nozzle is obtained. Then finite element analysis of the nozzle is performed using the above result as boundary condition. Results show that under high hydraulic pressure, stress gradient in the end of nozzle is great and the stress in the upper end inside the orifice is the highest, and stress concentration is obvious there. When a fillet with 0.05mm radius is made in the entrance of the orifice, the stress in that place has been reduced evidently. Stress concentration is eliminated.