A. Paykani, R. Khoshbakhti Saray, A. M. Mohammadi Kousha, M. T. Shervani Tabar,
Volume 1, Issue 2 (6-2011)
Abstract
In this study, a numerical simulation using the CFD software, FLUENT, has been conducted to examine the effect of various shapes of the venturi component sections in order to find the optimum venturi specifications to increase the EGR rate with minimum pressure loss at the part load operation range. The CFD results reveal that the venturi should be precisely optimized to introduce the required amount of EGR to the engine manifold. Then, the optimum venturi was manufactured, and it was installed on the engine intake system. By using the optimum Venturi EGR system instead of original system the 26% increase in EGR flow rate to the engine manifold is observed. In the second part of the paper, an experimental investigation was carried out on a “Lister 8-1” dual fuel (diesel – natural gas) engine to examine the simultaneous effect of inlet air pre-heating and EGR on performance and emission characteristics of a dual fuel engine. The use of EGR at high levels seems to be unable to improve the engine performance at part loads, however, it is shown that EGR combined with pre-heating of inlet air can slightly increase thermal efficiency, resulting in reduced levels of both UHC and NOx emissions. CO and HC emissions were reduced by 24% and 31%, respectively. The NOx emissions were decreased by 21% because of the lower combustion temperature due to the much inert gas brought by EGR and decreased oxygen concentration in the cylinder.
B. Jafari, D. Domiri Ganji,
Volume 3, Issue 2 (6-2013)
Abstract
Air pollution is one of the major issues about the diesel engines in todays' world. It is a special concern in
those areas that have difficulty meeting health-based outdoor air quality standards. Natural gas has low
emission and resource abundance and also conventional compression ignition engine can be easily
converted to a dual fuel mode to use natural gas as main fuel and diesel as pilot injection. The main object
of this work is to investigate the effect of number of injector nozzle hole on the combustion and exhaust
emission in a gas engine ignited with diesel fuel. We use one and three-dimensional simulation in parallel
way in order to analyze the performance and combustion process of a dual fuel engine. The experimental
results have also reported and compared with the simulated data.
