Injection Nozzles with Varying Hole Cross-section (NVHC) accomplished by laser drilling may influence the internal flow. The phenomena of cavitation flow in two types of NVHC (elliptic-shaped and hyperbolic-shaped) were simulated using mixed multiphase flow model coupled with cavitation model. The main objective is to analyze the effect of nozzle shape with different types on the distribution of cavitation and the outlet velocity. Simulation results show that the outlet velocity of elliptic-shaped nozzles is higher than that of cylindrical-shaped nozzles, and the outlet velocity distribution gives more uniform profile. Stronger outlet cavitation intensity is found in hyperbolic-shaped nozzles, which enhances the fluctuation of outlet flow and eventually improves the fuel break-up and atomization. The study also shows that, the inner flow state in NVHC is less sensitive to the fluctuation of inlet rounded radius than that in cylindricalshaped nozzle, and this improves the uniformity of flow discharge and spray in the process of multi-holes injection.
; 虞钢
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