CFD-3D Analysis of a Light Duty Dual Fuel (Diesel/Natural Gas) Combustion Engine

Abstract

This study investigated dual-fuel operation with a light duty Diesel engine with Natural gas over a wide engine load range. Natural gas was hereby injected into the intake duct, while Diesel was injected directly into the cylinder. At low loads, high fuel shares are critical in terms of combustion stability and emissions of unburnt hydrocarbons. Dual-fuel combustion has the advantage of providing diesel-like efficiency with Natural gas as the primary fuel, providing potential increases in efficiency of 50% while reducing emissions. Typically a small liquid fuel pilot is injected into a lean mixture of air and a more volatile fuel that is less inclined to auto-ignite. Often it is difficult to simulate the separate chemical effects of the two fuels. In present study we are using non premixed type of combustion model for better mixing and penetration of fuel and air so the complete combustion is achieved and emission is reduced by a great amount as compare to premixed method. NOx emission is reduced as compare to previous base research. Fluent accurately tracks flame propagation, which is critical for dual-fuel cases where the injection and auto-ignition of the liquid pilot fuel serves to initiate the flame propagation. In Fluent the simulation can simultaneously consider both auto-ignition and flame-propagation modes of combustion progress. Fluent fluid flow allows investigations of fuel or additive composition effects, impacts on liquid pilot amount and timing, and NOx reduction techniques such as EGR, etc.

Experimental and numerical study of the pollution formation in a diesel/CNG dual fuel engine

“…A blend of 70% n-heptane and 30% toluene is used to simulate the oxidation behavior of the diesel oil, whereas natural gas is represented by four component mixture of methane, ethane, propane and butane. The diesel/natural gas oxidation mechanism consists of 81 species and 421 elementary chemical reactions with associated rate coefficient expressions [23]. The convection and diffusion transport between different computational cells are modeled by the RNG (renormalization group) k-e turbulence model.…”

Numerical investigation of piston bowl geometry and swirl ratio on emission from diesel engines

“…To verify the models (see Table 3) used and numerical stability of the codes, computational results are compared with the experimental data available in the literature [31,32]. Fig.…”

Multi-zone model for diesel engine simulation based on chemical kinetics mechanism

“…However, 3 these models are costly because their computations are time consuming. The use of these models is widely reported in the literature [6][7][8][9].…”