Optimization of a Diesel Injector Nozzle

Abstract

Multiphase simulations based on the VOF (Volume of Fluid) approach, used in synergy with the cavitation Schnerr-Sauer method and the K-Epsilon turbulence model, have been conducted to study the behavior of an injector nozzle as a function of relevant structural parameters (such as the spray hole diameter and length). The related performances have been optimized in the framework of orthogonal experimental design and range analysis methods. As made evident by the results, as the spray hole diameter increases from 0.10 to 0.20 mm, the outlet mass flow rate grows by 243.23%. A small diameter of the spray hole, however, has a beneficial effect in terms of cavitation suppression. Moreover, rounding the spray hole can effectively increase the outlet mass flow rate and improve the flow characteristics while mitigating the cavitation phenomenon inside the spray hole. In particular, with the optimized nozzle design, the outlet mass flow rate can be increased by 13.33%, while the fuel vapor volume is reduced by 33.53%, thereby, leading to significant improvements in terms of flow characteristics and cavitation control.