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Partially Premixed Combustion (PPC) for low load conditions in marine engines using computational and experimental techniques
KTH, School of Engineering Sciences (SCI), Mechanics.
2013 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Diesel Engine has been the most powerful and relevant source of power in the automobile industry for decades due to their excellent performance, efficiency and power. On the contrary, there are numerous environmental issues of the diesel engines hampering the environment. It has been a great challenge for the researchers and scientists to minimize these issues. In the recent years, several strategies have been introduced to eradicate the emissions of the diesel engines. Among them, Partially Premixed Combustion (PPC) is one of the most emerging and reliable strategies. PPC is a compression ignited combustion process in which ignition delay is controlled. PPC is intended to endow with better combustion with low soot and NOx emission. The engine used in the present study is a single-cylinder research engine, installed in Aalto University Internal Combustion Engine Laboratory with the bore diameter of 200 mm. The thesis presents the validation of the measurement data with the simulated cases followed by the study of the spray impingement and fuel vapor mixing in PPC mode for different injection timing. A detailed study of the correlation of early injection with the fuel vapor distribution and wall impingement has been made. The simulations are carried out with the commercial CFD software STAR CD. Different injection parameters have been considered and taken into an account to lower the wall impingement and toproduce better air-fuel mixing with the purpose of good combustion and reduction of the emissions. The result of the penetration length of the spray and the fuel vapor distribution for different early injection cases have been illustrated in the study. Comparisons of different thermodynamic properties and spray analysis for different injection timing have been very clearly illustrated to get insight of effect of early injection. The parameters like injection timing, injection period, injection pressure, inclusion angle of the spray have an influence the combustion process in PPC mode. Extensive study has been made for each of these parameters to better understand their effects in the combustion process. Different split injection profiles have been implemented for the study of better fuel vapor distribution in the combustion chamber. The final part of the thesis includes the study of the combustion and implementation of EGR to control the temperature so as to get more prolonged ignition delay to accompany the PPC strategy for standard piston top and deep bowl piston top. With the injection optimization and implementation of EGR, NOx has been reduced by around 44%, CO by 60% and Soot by 66% in the standard piston top. The piston optimization resulted in more promising result with 58% reduction in NOx, 55% reduction in CO and 67% reduction in Soot. In both cases the percentage of fuel burnt was increased by around 8%.

Place, publisher, year, edition, pages
Keyword [en]
PPC, CFD, Split Injection, Ignition delay, EGR
National Category
Engineering and Technology
URN: urn:nbn:se:kth:diva-143761OAI: diva2:708379
Available from: 2014-03-27 Created: 2014-03-27 Last updated: 2014-03-27Bibliographically approved

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