Computational modeling of diesel and dual fuel combustion using converge cfd software

Abstract

In this study, CONVERGE CFD software is utilized for modeling processes in an internal combustion engine. CONVERGE includes advanced numerical techniques and physical models describing processes of spray, turbulence and combustion, and the nonlinear interactions of such processes. The objective of modeling dual fuel combustion is to gain better understanding of the combustion behavior in dual fuel engines. This modeling is performed in conjunction with experimental studies on a John Deere 6068H diesel engine. The engine is a Tier II, 6 cylinders, 6.8 liter, 4-stroke compression ignition engine with a compression ratio of 17:1 and a power rating of 168 kW at 2200 rpm. A natural gas fuel system was installed to deliver fuel upstream of the turbocharger compressor. The engine was operated at 1800 rpm through two different load points in diesel and dual fuel operating modes. Motored pressure, combustion pressure and net heat release rate (HRR) generated from the simulations are compared to the corresponding experimental results. Additionally, temperature, equivalence ratio, carbon monoxides and total hydrocarbon emissions distributions in dual fuel simulations at 12% and 75% loads are presented and discussed.