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Date of Award


Document Type

Campus Access Master's Report

Degree Name

Master of Science in Mechanical Engineering (MS)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Seong-Young Lee

Committee Member 1

Jeffrey D. Naber

Committee Member 2

Jianping Dong


In Internal Combustion (IC) engine, performance and emission levels are dependent on fuel-air mixture formation. The spray structure plays an important role in the IC engine as it determines the fuel air mixture formation in combustion chamber. In market, impinging jet injector is a novel technology which can generate better fuel atomization and spray formation.

This report studied the impinging spray characteristics under different engine-like conditions, which has been covered in three phases of work. Phase I includes the 4-hole and 5-hole series injectors under collision angle (90, 100 and 110 deg) to study hole pattern effect on spray formation. Phase II investigates the effect of injection pressure and chamber pressure on spray structure by using 4-hole impinging injector, under different chamber pressures, 0.1, 0.4, 1 and 2 bar and injection pressures 50, 100 and 200 bar. Phase III includes the different number of holes 2, 3, 4, 5, 6 and 8-hole injector for study of spray formation.

The impinging spray CFD simulation is done utilizing Eulerian–Lagrangian approach with KH-RT model for atomization under engine–like conditions. The spray post collision angle measurement is done using image processing toolbox in matlab. The spray visualization for droplet distribution is done using the averaging of simulation droplets data. The spray parameter such as post-collision angle (θ), bend angle (α) and spray distribution for droplet size, number density, mass and velocity are studied for impinging spray structure.

The fuel jet collision leads to a spray structure with three zones- inner core, intermediate with large droplets and outer periphery with small droplets scattered. The spray droplet distribution under different chamber pressures shows that droplet number density and mass concentration increase with chamber pressure condition. The overall spray structure has a strong dependence on the near nozzle spray distribution. The holes arrangement and number of holes in the injector has a strong influence on the spray spread area. The spray post collision angle and θ/ϕ ratio increase a little with the injection pressure. The spray post collision angle shows a strong dependence with chamber pressure and decreases with the increase in chamber pressure condition. A comparative study of multi-hole injector will give a better understanding about spray structure dependence on the injector holes design.