Yazar "Raman, Vallinayagam" seçeneğine göre listele

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    Effect of intake port design modifications on diesel engine characteristics fuelled by pine oil-diesel blends
    (TAYLOR & FRANCIS INC, 2022) Malaiperumal, Vikneswaran; Saravanan, Chidambaram Ganapathy; Raman, Vallinayagam; Kirubagaran, Raj Kiran; Pandiarajan, Premkumar; Sonthalia, Ankit; Varuvel, Edwin Geo
    The effect of the modified intake port with various inclined nozzle angles such as 30 degrees, 60 degrees, and 90 degrees on the diesel engine characteristics when operated with pine oil-diesel blends is investigated. Prior to the engine experimental study, a computational analysis was performed to investigate the impact produced on the flow field parameters of an engine due to modified intake port design. The numerical study revealed increased swirl velocity and turbulence for intake port with a 60 degrees single-pass configuration compared to other design configurations. With evidence of improved swirl velocity and the proposed modified intake port design from the numerical study, an experimental investigation was performed using pine oil blends in the diesel engine with modified intake port configurations. The preliminary engine test findings with standard intake port design indicated that P50 (50% pine oil + 50% diesel) has higher peak engine cylinder pressure and heat release rates than P10 (10% pine oil + 90% diesel). Additionally, the 60 degrees single-pass configuration showed further increase in peak pressure and peak heat release followed by standard and other intake port design configurations. At high load, the P50 blend showed a 12.3% increase in BTE for 60 degrees intake port design configuration in comparison to the standard design configuration. While for the same blend, the engine out emissions like hydrocarbon (HC) and smoke were reduced by about 6.6% and 17.6%, respectively, and nitrogen oxide (NOX) emission was increased by 29% for the 60 degrees single-pass configuration when compared to the standard design configuration. Overall, the intended intake port design modification strategy increased the swirl velocity and turbulence, which improved the air/fuel mixing and combustion. This study identifies 60 degrees single-pass configuration as an optimum design on account of the aforementioned improved engine combustion, performance, and emissions.
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    Experimental investigations on in-cylinder flame and emission characteristics of butanol-gasoline blends in SI engine using combustion endoscopic system
    (Elsevier, 2024) Kumaravel, S.; Saravanan, C. G.; Raman, Vallinayagam; Vikneswaran, M.; Sasikala, J.; Josephin, J. S. Femilda; Alharbi, Sulaiman Ali
    The objective of this study is to characterize the in-cylinder flames of butanol-gasoline blends in a spark ignition (SI) engine. The experiments were performed using butanol-gasoline blends prepared in the ratio of 10:90, 20:80, and 30:70 by volume. The in-cylinder combustion was visualized and captured using a combustion endoscopic system. From the captured combustion images, spatial flame distribution was evaluated for butanol-gasoline fuel blends. Furthermore, combustion, emission, and performance characteristics were investigated in a SI engine for the same blends. The engine test results were rationalized from the flame characterization results of butanol-gasoline combustion to improve the fundamental understanding. The experimental outcome is that the flame spread region (%) was found to be higher for butanol blends when compared to sole gasoline fuel. The addition of butanol to gasoline increased the flame speed and consequently increased the combustion burn rate, as well as the pressure and heat release rate within the cylinder. The brake thermal efficiency of the engine increased with increasing butanol concentration in the blend. In addition, the butanol-gasoline blends showed decreased CO and HC emissions when compared to gasoline but reportedly increased NO emission for butanol-blended gasoline blend fuels. Overall, this study concludes that butanol has the potential to be used as a supplement to gasoline due to improved flame and engine characteristics and can be used in the conventional gasoline engine without any major engine modification.
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    Experimental study of droplet combustion and diesel engine characteristics for azolla biodiesel
    (TAYLOR & FRANCIS INC, 2022) Ganapathy, Saravanan Chidambaram; Seshadri, Thiruvenkatachari; Jayaraman, Sasikala; Raman, Vallinayagam; Malaiperumal, Vikneswaran; Varuvel, Edwin Geo; Joseph Shobana Bai, Femilda Josephin
    This study pertains to studying the feasibility of the third-generation biodiesel obtained from one of the algae species known as Azolla microphylla by exploring their fundamental droplet combustion behavior and diesel engine characteristics. Firstly, the droplet evolution and burn rate are investigated for diesel, Azolla100, and Azolla50 (50% biodiesel +50% diesel) based on the experimental study of suspended droplet combustion. The diesel droplet showed steady combustion with linear regression for the decrease in droplet surface with time throughout its lifetime, while the Azolla100 and Azolla50 droplets showed a linear trend initially, and after a certain point, they resulted in a non-linear trend as a result of disruptive burning. The evaporation and burn rate was found to be higher for Azolla100 and Azolla50 than diesel during the steady burning period and thereafter it decreased with increasing Azolla concentration. The time evolution of droplet combustion images indicated that with increasing biodiesel concentration, the combustion duration was decreased due to secondary droplet ejections and microexplosion, and the residue burning duration was increased. The microexplosion increased the rate of combustion, however, droplet ejection resulted in incomplete combustion. Secondly, the engine experiments were performed for Azolla50 at different fuel injection pressures. The results showed that in-cylinder pressure and Brake thermal efficiency (BTE) for Azolla50 at 300 bar injection pressure were lower than diesel due to limitations with the physical properties of biodiesel. In order to improve the engine characteristics of Azolla50, this study increased the fuel injection pressure to 900 bar. As a result, the BTE for Azolla50 at 900 bar injection pressure is improved by 9.2% and 10.2% at low and full load conditions, respectively, compared to Azolla50 at 300 bar injection pressure. Overall, the spray-driven combustion for Azolla50 is limited by the physical properties of the biodiesel, which affects the mixture formation. On the other hand, the microexplosion and droplet ejection observed with the biodiesel during the combustion study would favor the combustion by improving the atomization and mixing process.
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    An experimental study of the effects of fuel injection pressure on the characteristics of a diesel engine fueled by the third generation Azolla biodiesel
    (Elsevier, 2022) Thiruvenkatachari S.; Saravanan, C. G.; Raman, Vallinayagam; Vikneswaran, M.; Femilda Josephin, J. S.; Varuvel, Edwin Geo
    This study focuses on effectively utilizing the biodiesel extracted from Azolla (third-generation biofuel), which is regarded as a renewable energy source, for fueling diesel engines. Biodiesel is unique due to its increased viscosity and different fatty acid composition, which proved difficult to attain better engine performance with a mechanical type injection system. This study expands on the previous investigation in modifying the fuel system when using Azolla biodiesel by using a common rail fuel injection system with wider injection flexibility. Considering the lack of more engine optimization studies for Azolla biodiesel, a parametric study is conducted by changing the fuel injection pressure in the range between 300 bar and 900 bar for diesel engine fueled by B20 (20% Azolla +80% diesel) blend. The experimental engine study revealed that the physical properties of the fuel adversely affect the in-cylinder combustion, which leads to poor engine performance and higher emissions at lower injection pressure (300 bar) for B20 when compared to diesel. As the injection pressure increases, the fuel atomization and other spray characteristics are enhanced and thereby improve the combustion. The Brake Thermal Efficiency (BTE) for B20 at 900 bar injection pressure is 3% higher than the diesel fuel at 300 bar injection pressure under full load conditions. The HC, CO, and smoke emission in the engine exhaust for B20 at 900 bar injection pressure was reduced by 13.3%, 28.5%, and 12.3%, respectively, when compared to diesel. Overall, this study recommends the operation of Azolla biodiesel blend in diesel at 900 bar fuel injection pressure to attain improved engine characteristics.