Faculty Publications

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Author: search.filters.author.Gottekere Narayanappa, K.G.Has files: No

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    Experimental investigation of overall cooling effectiveness on combustion chamber liner with and without impingement holes
    (American Society of Mechanical Engineers, 2015) Jesuraj, F.; Rajendran, R.; Gottekere Narayanappa, K.G.; Yepuri, G.B.; Sasikumar, V.; Poozhiyil, S.
    The gas turbine combustor liner which is subjected to high temperature requires efficient cooling. In earlier days concept of slot film cooling is utilized in the combustion liners and in modern combustors multiple row film cooling (effusion cooling) is mainly used. This study aims at the experimental investigation of overall film cooling effectiveness of an effusion plate with and without impingement holes at the backside. The experiments are done at different blowing ratios and the surface temperature measurements are taken using infrared thermography. The effusion and impingement holes are arranged in staggered manner on two parallel plates and each effusion hole is surrounded by four impingement holes. Effusion holes are drilled at an angle of 27° and the impingement plate is kept at a distance of 6D away from the effusion plate. The experiments are done on the effusion plate with and without impingement plate at the backside. The results show, increase in cooling effectiveness as the blowing ratio increases. The comparative results shows that at a particular blowing ratio the overall cooling effectiveness is higher for effusion plate with impingement holes at the backside due to the higher convective heat transfer coefficients produced by the impinging jets at the cold side of the effusion plate. © Copyright 2015 by ASME.
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    Effect of Hot EGR on Combustion, Performance and Emission Characteristics of Vateria Indica Biodiesel in CI Engine
    (American Institute of Physics, 2024) Rao, G.; Gottekere Narayanappa, K.G.; Herbert, M.A.
    Vateria Indica Linn is a tree belonging to Dipterocarpaceae family. The seed of Vateria Indica Linn contains about 19% of oil/fat. By a novel method the oil/fat in the seed is converted into biodiesel. In the previous work the effect of Vateria Indica Methyl Ester (VIME biodiesel) on engine parameters is tested in a single cylinder CI engine by varying injection pressure (180 to 220bar in step of 20bar) and injection timing (19, 23 and 27 bTDC). VIME is blended with diesel (10%, 15%, 20% and 25% of biodiesel v/v), which were called as B10, B15, B20, B25. Based on this works injection pressure of 220bars and injection timing of 27bTDC for B25 blend is selected as best. But in the previous work NOx emission is found to be considerable for the best parameters. The purpose this work is to study the effect of hot EGR on combustion, performance and emission characteristics of a CI engine with diesel and B25 blend with 5% and 10% hot EGR for NOx mitigation. Here it can be noted that EGR lowers the performance but the emission characteristic is better compared to base line diesel. Based on the present work 10% EGR is recommended for blend B25 at selected optimum operating parameters. © 2024 American Institute of Physics Inc.. All rights reserved.
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    An overview of after-treatment systems for diesel engines
    (Springer Verlag service@springer.de, 2018) Ayodhya, A.S.; Gottekere Narayanappa, K.G.
    Vehicular pollution has become a major problem in urban areas due to the exponential rise in the number of automobiles. Typical exhaust emissions which include nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), soot, and particulate matter (PM) undoubtedly have an unpleasant effect on the environment. Several pollution control bodies are taking this subject seriously and issuing stringent emission norms which are to be complied strictly. Thus, regulation of these harmful pollutants is the need of the hour. Alternative fuels such as biodiesels and alcohols which are considered as a potentially viable solution for the problem of fossil fuel depletion also tend to require exhaust gas after-treatment in order to comply with the upcoming emission norms. Hence, this paper attempts to give a brief insight on the development and advances of different after-treatment devices like diesel particulate filter (DPF), lean NOx trap (LNT), diesel oxidation catalyst (DOC), and selective catalytic reduction (SCR). © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
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    Influence of low-temperature combustion and dimethyl ether-diesel blends on performance, combustion, and emission characteristics of common rail diesel engine: a CFD study
    (Springer Verlag service@springer.de, 2017) Lamani, V.T.; Yadav, A.K.; Gottekere Narayanappa, K.G.
    Due to presence of more oxygen, absence of carbon-carbon (C-C) bond in chemical structure, and high cetane number of dimethyl ether (DME), pollution from DME operated engine is less compared to diesel engine. Hence, the DME can be a promising alternative fuel for diesel engine. The present study emphasizes the effect of various exhaust gas recirculation (EGR) rates (0–20%) and DME/Diesel blends (0–20%) on combustion characteristics and exhaust emissions of common rail direct injection (CRDI) engine using three-dimensional computational fluid dynamics (CFD) simulation. Extended coherent flame model-3 zone (ECFM-3Z) is implemented to carry out combustion analysis, and k-?-f model is employed for turbulence modeling. Results show that in-cylinder pressure marginally decreases with employing EGR compared to without EGR case. As EGR rate increases, nitrogen oxide (NO) formation decreases, whereas soot increases marginally. Due to better combustion characteristics of DME, indicated thermal efficiency (ITE) increases with the increases in DME/diesel blend ratio. Adverse effect of EGR on efficiency for blends is less compared to neat diesel, because the anoxygenated region created due to EGR is compensated by extra oxygen present in DME. The trade-off among NO, soot, carbon monoxide (CO) formation, and efficiency is studied by normalizing the parameters. Optimum operating condition is found at 10% EGR rate and 20% DME/diesel blend. The maximum indicated thermal efficiency was observed for DME/diesel ratio of 20% in the present range of study. Obtained results are validated with published experimental data and found good agreement. © 2017, Springer-Verlag Berlin Heidelberg.
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    Experimental Analysis of Synergetic Effect of Part-Cooled Exhaust Gas Recirculation on Magnetic Field-Assisted Combustion of Liquefied Petroleum Gas
    (Springer Science and Business Media Deutschland GmbH, 2020) Oommen, L.P.; Gottekere Narayanappa, K.G.; Shivaprasad, S.K.
    Magnetic field-assisted combustion has been under the focus of research for the last three decades around the globe. The effects of strong uniform and gradient magnetic fields on flame development, behaviour and propagation have been studied, and their applications have been experimented on Internal Combustion Engines. The present work investigates the synergetic effect of part-cooled EGR on the magnetic field-assisted combustion of liquefied petroleum gas in a multicylinder MPFI spark-ignited engine modified for neat LPG operation. Sintered neo-delta magnets with radial magnetization pattern of four different magnetic intensities (0G, 3200G, 4800G and 6400G) are fastened to the fuel line near to the gas injector with a non-magnetic stainless steel integument to prevent any loss of magnetic intensities during the operation. A portion of the exhaust gas is channelled to an intercooler and an optimum percentage of the partially cooled gases are inducted into the inlet manifold for combustion. The experimental study concludes that the optimum flow rate of part-cooled EGR acts synergistically with the applied magnetic fields to enhance the combustion characteristics of LPG emanating an improved fuel economy of 13.8% and brake thermal efficiency of 3.9%. The increased emission of oxides of Nitrogen which is the major setback of LPG combustion can be addressed through the combined effect of part-cooled EGR and magnetic field-assisted combustion. Moreover, the reduction in stability of combustion through the recirculation of exhaust can also be balanced by the applied magnetic field. © 2020, King Fahd University of Petroleum & Minerals.
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    Assimilative capacity approach for air pollution control in automotive engines through magnetic field-assisted combustion of hydrocarbons
    (Springer Science and Business Media Deutschland GmbH, 2021) Oommen, L.P.; Gottekere Narayanappa, K.G.
    Deterioration of air quality through the combustion of hydrocarbon fuels has been one of the global transboundary problems put before the research community since last five decades. According to the updated statistics, 79% of energy needs in India are met by fossil fuel combustion which results in the emission of toxic pollutants like carbon monoxide, oxides of nitrogen, and unburned hydrocarbons. Air quality has seriously been affected in many parts of India, and statistically, 13 out of 15 most polluted cities in the world lie in India. Magnetic field-assisted combustion has been proven as a reliable technology in internal combustion engines for enhancing the combustion of fuels and reduction of harmful emissions that are the byproducts of incomplete combustion of fuels. In the present work, the magnetic field-assisted combustion of a liquid-phase and a gas-phase fuel (gasoline and LPG) has been studied in a multicylinder automobile engine replicating on road driving conditions in a laboratory focusing on the levels of emissions in comparison with normal combustion of both the fuels. The experimental study concludes that the applied magnetic field positively influences combustion, resulting in reduced level of emission of toxic components irrespective of the phase of hydrocarbon fuels. It is also observed that the percentage reduction in emissions increases with increase in intensity of magnetization. The maximum reduction obtained for CO and UBHC emissions through this technique is 20.58% and 14.47%, respectively. The effectiveness of MFAC in countering air pollution from vehicular exhaust is also studied with respect to fuel phase and mode of operation. The effectiveness of MFAC is observed to be more in high-speed operation of the engine and decreases in the order CO > UBHC > NO. The obtained emission results have a cumulative significance as 45% of total air pollution in India is caused by combustion of hydrocarbons in automotive engines. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.