Development of a 3D CFD model to investigate the effect of the mixing quality on the CNG-diesel engine performance

Abstract

ABSTRACT: In this paper Computational Fluid Dynamics (CFD) analysis software (CFD-ACE) is used to investigate flow behaviour of methane and air in a CNG-air mixer to be used for CNG-Diesel dual fuel stationary diesel engine. The results of the simulation show that, the eight-hole mixer give superior performance as compared to the four-hole mixer. Further analysis were then done on the eight-hole mixer to investigate the effect of engine speed on the mass flow rate of CNG and λ (ratio of actual to stochiometric air fuel ratio). The second half of this paper represents a compression results between the performances of a single cylinder research Compression Ignition CI engine; i) fuelled with Compressed Natural Gas-diesel system and conventional CI engines fuelled by conventional diesel. The engine was equipped with the simulated 8 holes Venture mixer, the results shows that there is significant reduction of the exhaust gas emission components such as NOx, CO and CO2. in comparison to the conventional diesel engine. This work shows that by using dual fuel system (with Venturi mixer) NOx, CO and CO2 concentrations in the exhaust gases were, on average, reduced by 54%, 59% and 31% respectively. The average power output from the engine operating at dual fuel was 10% higher than that operating on diesel over the tested range of engine speeds.