Faculty Publications
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Item Experimental studies on cyclic variations in a single cylinder diesel engine fuelled with raw biogas by dual mode of operation(Elsevier Ltd, 2020) Jagadish, C.; Gumtapure, V.In this research work, cycle-by-cycle variations of a single cylinder, diesel engine operated with raw biogas is investigated. The biogas used to run the engine is obtained from food waste and as the composition of 88.10%-CH4 + 11.895%-CO2. To study the combustion characteristics, the naturally aspirated diesel engine is converted into dual mode by inducting the biogas into the intake manifold for different proportions from BG20 to BG60 with a step of 10% is mixed with air (i.e. BG60-60% of biogas by mass) respectively. Combustion parameters are measured and recorded by the means of the data acquisition system (DAQ) for 100 combustion cycle. By determining the parameters such as standard deviation, coefficient of variation and return map, the cycle variability is analyzed. From the experimental result, it is observed that as the engine is operated at higher loads and as the biogas is increased from BG20 to BG60 the cyclic variations for maximum cylinder pressure (Pmax) and indicated mean effective pressure (IMEP) increases. Coefficient of variation of Pmax for BG20 and BG40 is lower by 2.3% and 11.98% as compared to diesel. From time return map, BG40 showed good combustion stability and lesser NOx emission compared to diesel. © 2020 Elsevier LtdItem Experimental investigation of shellac wax as potential bio-phase change material for medium temperature solar thermal energy storage applications(Elsevier Ltd, 2022) B.V., B.V.; Thanaiah, K.; Gumtapure, V.Thermal performance of shellac wax as a novel bio-phase change material (BPCM) and Therminol®-55 as heat transfer fluid (HTF) in a vertical shell and tube latent heat thermal energy storage (LHTES) unit is analyzed experimentally. Operational parameters considered, namely HTF flow rate and inlet temperature in the range of 2–5 LPM and 100–120 °C, respectively. The comprehensive study of contours and plots reveals the impact of natural convection and the progress of the melting and solidification front in the charging and discharging process. As the HTF flow rate increases, the charging rate improves considerably, and a maximum reduction in melting time is obtained as 43.6% for 4 LPM. The maximum reduction in melting time and storage efficiency are 42.2% and 73.4%, respectively, at 120 °C and 4 LPM. However, the discharging process's increased flow rate has no significant effect on solidification and discharge efficiency, which attributes the dominant mode of heat transfer is conduction during the solidification. Shellac wax storage efficiency is comparable to existing paraffin wax, stearic acid and palmitic acid-based LHTES unit. In this regard, shellac wax can be a potential Bio-PCM for medium temperature range (60–80 °C) solar thermal applications such as domestic water heating and food drying. © 2021 International Solar Energy SocietyItem Experimental Study on the Effect of Injection Timing on a Dual Fuel Diesel Engine Operated With Biogas Derived From Food Waste(American Society of Mechanical Engineers (ASME), 2022) Chandrashekar, J.; Gumtapure, V.The present work emphasizes the effects of injection timing on the characteristics of a 5.2-kW powered four-stroke diesel engine using biogas and its heat loss analysis. The biogas is obtained from food waste consisting of methane (CH4)-88.1% and carbon dioxide (CO2)-11.8% as the composition. The biogas (BG) is selected by mass basis ranging from 20% to 60% with 10% increments and is used to operate the engine by dual-fuel mode. The effect of three injection timings such as 25.5 deg (retarded), 27.5 deg (actual), and 29.5 deg (advanced) before top-dead center (bTDC) under dual-mode operation to enhance the properties of the engine is studied, and the results are compared with diesel mode at actual injection timing. Maximum brake thermal efficiency of 30.1% was observed for BG20 operated at 29.5-deg bTDC injection timing (IT). The dual mode operated at the injection timing of 29.5-deg bTDC showed an increase in cylinder pressure compared to diesel by 11.9% at full load conditions, whereas carbon monoxide emission was lower by 5.2% at 29.5-deg bTDC IT than diesel, and nitrogen oxide emission was lower at 25.5 deg bTDC IT than diesel mode by 45%. Besides, at 75% engine load, the least amount of heat losses was observed for BG50 exhibiting effective conversion of fuel energy into equivalent work higher than that of diesel by 2.2%, respectively. © © 2022 by ASME.