Biplab Kumar Debnath

Influence of Emulsified Palm Biodiesel as Pilot Fuel in a Biogas Run Dual Fuel Diesel Engine

This study attempts to explore the influence of emulsified palm biodiesel as a pilot fuel in a biogas run dual fuel engine. The intention is to achieve diesel-equivalent performance from a diesel engine, together with a reduction in engine emissions, with complete replacement of fossil diesel with renewable fuels. The results of this study are compared to those for a neat biodiesel (Jatropha)-biogas dual fuel engine run at identical engine settings. For baseline comparison, the results are also compared with a standard diesel run. The results show that with the presence of biogas, emulsified biodiesel as a pilot fuel can present a better dual fuel efficiency (41%) and a lower energy consumption (38%) than neat biodiesel in a piloted study. Also, the presence of a microexplosion of emulsified biodiesel was found to reduce the pilot fuel consumption with the presence of biogas, especially at lower loads, where the burning rate of biogas usually slows down due to the lean gas-air mixture and cooler charge temperature. In addition, emulsified palm biodiesel successfully brings the peak cylinder pressure (PCP) closer (8 degrees ATDC) to top dead center (TDC). This elevates the magnitude of the PCP, which increases the expansion ratio and hence improves engine efficiency. With the presence of emulsified biodiesel, the supply of biogas is found to get reduced, especially at higher loads, which in turn reduces the hydrocarbon emission. However, other emission characteristics are not as exciting, and hence emulsified biodiesel in biogas dual fuel mode needs to be further explored at various engine-operating characteristics in order to obtain a superior emission performance

Computational fluid dynamics analysis of a combined three-bucket Savonius and three-bladed Darrieus rotor at various overlap conditions

In this paper, a computational fluid dynamics analysis using the FLUENT package 6.2 was carried out to predict the performance characteristics such as power coefficient (Cp), torque coefficient (Ct), and tip speed ratio of a combined three-bucket Savonius and three-bladed Darrieus rotor for various overlap conditions, namely, 16.2%, 20%, 25%, 30%, and 35%. In the upper part of the rotor model, there was a three-bucket Savonius rotor of bucket diameter of 8 cm and height of 10 cm, whereas, in the lower part, there was a three-bladed Darrieus rotor of blade diameter of 8 cm and height of 10 cm. A two-dimensional unstructured computational grid was developed for the combined Savonius–Darrieus rotor model. A k-e turbulence closure model with enhanced wall treatment function was chosen. A first-order upwind discretization scheme was adopted for pressure-velocity coupling of the flow. The values of Cp and Ct obtained computationally were then compared with those of the values of Cp and Ct obtained experimentall...

Theoretical Route toward the Estimation of Second Law Potential of an Emulsified Palm Biodiesel Run Diesel Engine

AbstractThe application of biodiesel as an alternative to diesel is well recognized. However, having a lesser calorific value than diesel, it results in a lower power and efficiency. This can suitably be improved by emulsifying biodiesel with water. However, the properties of biodiesel emulsions are not similar to that of diesel. Hence, the energy and availability distribution of a biodiesel emulsion–run engine will not be identical to that of a diesel-run engine at standard diesel settings. To enlighten this ambiguous fact of literature, an energy-exergy analysis has been performed for a water-in-biodiesel emulsion run diesel engine for a set of compression ratios (CRs) and injection timings (ITs) at full engine load. The biodiesel considered for the study is palm oil methyl ester (POME). The parameters analyzed are the energy and exergy potential of fuel input, shaft work, cooling water, exhaust gas, and exergy destruction. Side by side, the effects of the variation of CR and IT on peak pressure, peak h...

Effect of compression ratio and injection timing on the performance characteristics of a diesel engine running on palm oil methyl ester

Diesel fuel has a limited resource, and concerns over environmental pollution are leading to the use of ‘bio-origin fuels’ as they are renewable and environmentally benign. Palm oil methyl ester, an esterified biofuel, has an excellent cetane number and a reasonable calorific value. Besides, palm oil methyl ester (C18.07H34.93O2) has around 11.25% of oxygen bonded in its molecular structure which increases its burning intensely. Thus, it closely resembles the behavior of diesel. However, being a fuel of different origin, the standard design limits of a diesel engine is not suitable for palm oil methyl ester. Therefore, in this work, a set of design and operational parameters are studied to find out the optimum performance of a palm oil methyl ester run diesel engine. The parameters varied are the compression ratio (CR) and injection timing (IT) along with load in a variable compression ratio diesel engine. The palm oil methyl ester run engine is investigated for its performance, combustion and emission characteristics. The combination of CR = 18 and IT = 20°BTDC improves the efficiency by 8% and cuts the exhaust gas temperature by 5%. Moreover, the palm oil methyl ester run engine lowers the ignition delay which further gets reduced by 7% and 12% with CR augmentation and IT retardation, respectively. The increase in CR trims down carbon monoxide by 40%, nitrogen oxides by 46% and hydrocarbon by 40%; however, it increases carbon dioxide emission by 19%. The IT retardation reduces the carbon dioxide emission by 16%.

Experimental Analysis of Emulsified Palm Oil Methyl Ester Towards Alternative Diesel Fuel

Palm oil methyl ester (POME) produced from crude palm oil have some excellent properties which makes it a feasible alternative to diesel fuel. However, its higher oxygen content makes it nitrogen oxide emission prone when burned in diesel engines. This problem can be resolved by emulsifying POME with distilled water in the presence of suitable surfactant. Two phase water in oil emulsion is prepared by using ultrasonic bath sonication. SPAN 80, a lipophilic surfactant is used for 1% by volume to prepare the emulsion. Water quantity in the emulsion is varied by 5% and 10% by volume and stability study is performed. It is found that emulsion with 5% water is more stable. Thereafter, POME emulsion samples are prepared with 5% water and tested in a variable compression ratio diesel engine. The performance and emission characteristics are investigated for a set of loads and compression ratios (CR). The experimental observations show that 5% water in POME produce 3.5% lower brake thermal efficiency and 11% higher brake specific fuel consumption as compared to baseline diesel. Furthermore, the exhaust gas temperature and other emissions like oxides of carbon, oxides of nitrogen and hydrocarbon for the emulsified POME are found to be lower than the baseline diesel.Copyright

Effect of Compression Ratio on the Performance Characteristics of a Palm Oil Methyl Ester Run Diesel Engine

Palm Oil Methyl Ester (POME) is a very promising alternative renewable biofuel. This is because it has a better cetane number and a comparable lower calorific value with respect to its competitors. However, due to difference in molecular composition and hence dissimilar properties, it does not perform proficiently in diesel engine with standard design and operating parameters. Therefore, a study is arranged to realize the effect of compression ratio variation on POME run in diesel engine. The load is varied from ‘no load’ to ‘full load’ with six equal intervals. During this study, standard diesel injection timing is maintained unaffected. The study conveys that at higher compression ratio, POME causes reduction in brake fuel consumption and thereby increases the engine efficiency. The increase in compression ratio also causes smoother combustion, lower ignition delay with early heat release than diesel operation. The detrimental emission quantities in the form of carbon monoxide, oxides of nitrogen and hydrocarbon emissions are also cut down with presence of POME in the diesel engine at high compression ratio. Thus, POME can be regarded as a good alternative fuel for diesel engine for locomotive applications.Copyright

Prediction of performance coefficients of a three-bucket Savonius rotor using artificial neural network

This article deals with an artificial neural network analysis to predict the power and torque coefficients of a three-bucket Savonius rotor. The input data sets under different overlap conditions are taken from the experiments performed in a subsonic wind tunnel. Thirty input and output data sets are used. Out of these, 24 data sets are utilized for training and the remaining 6 are employed for testing analysis. The data sets are separated randomly. Three parameters, viz., the overlap ratio, the tip-speed ratio, and the angular velocity, are considered as input variables of the network. The power and torque coefficients are taken as output variables. The hidden layers are varied in the range from one to three. The quantities of neurons in the hidden layers are altered network-by-network for best matching. The back-propagation perceptron-learning algorithm which is commonly used is employed to train and test the networks. Eight network configurations are trained and tested simultaneously and the global err...

Simulation of Combustion and Emission Characteristics in a Dual Fuelled Diesel Engine

In this paper, Computational Fluid Dynamics (CFD) approach is adopted to study the combustion and emission progression in a single cylinder four stroke diesel engine, operated in both diesel and dual-fuel modes. The study of dual-fuel mode is performed by using synthesis gas (syngas) with 75:25 and 50:50 volumetric combinations of hydrogen and carbon monoxide, respectively. The modeling and meshing of the constant volume combustion chamber is carried out by using GAMBIT tool. The meshing of the combustion chamber is performed using tetrahedral elements and the k–e turbulence model is introduced along with non-premixed combustion modeling. The modeled hemispherical-piston-top combustion chamber is then simulated in FLUENT solver across the experimental boundary conditions at 40%, 60%, 80% and 100% of full load for both diesel and dual-fuel. The results of simulation incorporate the study of maximum combustion temperature, maximum combustion velocity and H2 O mole fraction subsequent to combustion. Further, the concentrations of emissions have also been investigated for both diesel and dual-fuel modes. The results of simulations show a good agreement with the corresponding experimental data.Copyright