Analysis of the effect of charge air temperature and humidity on the combustion process of diesel engines at Heladhanavi Power Plant, Puttalam, Sri Lanka

by Gayan Kahandagamage

Institution: KTH Royal Institute of Technology
Year: 2015
Keywords: Engineering and Technology; Mechanical Engineering; Energy Engineering; Teknik och teknologier; Maskinteknik; Energiteknik
Record ID: 1370750
Full text PDF: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166176


Heladhanavi 100MW Diesel Power Plant in Puttalam, Sri Lanka consists of six 18V46 Wartsila turbocharged air cooled engines. Specific fuel consumption of the engines varies with the ambient conditions. It has been seen in hotter days fuel consumption is higher comparatively to cooler days. This study was conducted as per the requirement to find out the reasons behind this variation of the fuel consumption and to quantify the effects on the efficiency with respect to the charge air properties in relation to temperature and humidity. The effect of charge air temperature was analyzed performing two sets of experiments. A combustion analysis experiment (experiment 1) was performed to monitor what happens inside the combustion chamber during day and night times. Simultaneously a fuel consumption test was performed using the direct method with the fuel flow meter and energy dispatch readings taking in to the consideration. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. A flue gas analysis test (experiment 2) was performed to determine the efficiency variation in day and night times through the indirect method. Along with this analysis the direct method was followed up to calculate fuel consumption to compare the results from the both tests. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. It was confirmed the specific fuel consumption is positively affected by the charge air temperature while the efficiency is negatively affected. From the literature review it was found out the humidity in charge air affects positively on the fuel consumption while efficiency is negatively affected. The charge air temperature affects the ignition delay period so that the peak pressure and then the combustion efficiency. The efficiency improvement is further confirmed by the flue gas analysis experiment as the losses in the flue gas reduce in night time comparatively to the day time. Finally it can be concluded that under the prevailing ambient conditions in Puttalam, Sri Lanka, the effect of charge air temperature is more prominent than the effect of humidity on the combustion process. Therefore, proper cleaning and maintaining of the charge air coolers are the most important factors to maintain the charge air temperature and relative humidity inside charge air receiver at a lowest value.