[Show abstract][Hide abstract] ABSTRACT: This study evaluates the effect of anti-corrosion additives such as 8% and 16% (vol.%) palm olein oil (PO) with ordinary diesel (OD) fuel on engine operation, emission behavior, engine part wear, and lubrication characteristics. This experiment was conducted on 4-cylinder and 4-stroke IDI diesel engine at different engine speed ranging from 1200 to 2800 RPM with 30% throttle setting under full load condition. The properties of the palm olein oil blends meet the ASTM D6751 and EN 14214 standards. At 2000 rpm, the experimental results revealed that the POD8A (0.2% Additive + 8% PO + 92% OD) and POD16A (0.2% Additive + 16% PO + 84% OD) blended fuels produced 0.5% and 0.51% higher brake power as well as 1.45% and 1.25% higher torque than same blends without additive, respectively. In comparison with ODF, the brake specific fuel consumption (BSFC) was found 1.8% and 3.1% higher for POD8A and POD16A blends, respectively. Anti-corrosion additive is found more effectual in enhancing the engine performance as such additive helps in timely ignition for complete burn in the combustion chamber. The results from engine emission indicated that POD8A and POD16A blended fuel reduced CO emissions by 11% and 6.6% and NOx emission by 2.5% and 1.09%, respectively in compared with OD fuel. Although HC emissions for all blended fuel and OD fuel increased at higher engine speed, the average HC emissions of all blended fuel were not higher than OD fuel. The application of anti-corrosion additives in POD blends reduced ferrous (Fe) wear debris concentration (WBC) by 17.3%. The reductions in WBC were about 16.1%, 10.8%, and 19.3%, 17.6% for copper (Cu) and aluminum (Al), respectively. An exception was lead (Pb) which yielded higher WBC for all POD blended fuels in compared with OD fuel. Finally, it can be concluded that palm olein oil with additives gives better engine performance, reduces unnecessary exhaust emissions and wear debris concentration of engine parts.
Energy Conversion and Management 11/2014; 87:48–57.
[Show abstract][Hide abstract] ABSTRACT: In order to harvest solar energy, thermal energy storage (TES) system with Phase Change Material (PCM) has been receiving greater attention because of its large energy storage capacity and isothermal behavior during charging and discharging processes. In the present experimental study, shell and tube TES system using paraffin wax was used in a water heating system to analyze its performance for solar water heating application. Energy and exergy including their cost analyses for the TES system were performed. Accordingly, total life cycle cost was calculated for different flow rates of the Heat Transfer Fluid (HTF). With 0.033 kg/min and 0.167 kg/min flow rates of water as HTF, energy efficiencies experienced were 63.88% and 77.41%, respectively, but in exergy analysis, efficiencies were observed to be about 9.58% and 6.02%, respectively. Besides, the total life cycle cost was predicted to be $ 654.61 for 0.033 kg/min flow rate, which could be reduced to $ 609.22 by increasing the flow rate to 0.167 kg/min. Therefore it can be summarized that total life cycle cost decreases with the increase of flow rate.
International Communications in Heat and Mass Transfer 10/2014;
[Show abstract][Hide abstract] ABSTRACT: This paper presents stress intensity factors (SIFs) and fatigue growth analyses of a corner crack emanating from a pinhole of a cylinder under cyclic tension. No such work has been reported in the literature. Stress intensity factors for different crack aspect ratios and pinhole sizes in different diameters of solid cylinder are presented. A larger SIF was found at the smaller crack size of a or c in a larger diameter of a pinhole of the smaller-diameter cylinder. Crack growths at the pinhole edge were found to be faster than those at the cylinder edge.
[Show abstract][Hide abstract] ABSTRACT: Diminishing fossil fuel reserves and environmental concerns have stimulated research into biofuels as potential renewable and sustainable replacements for fossil diesel. The present research aimed to investigate the feasibility of using mustard biodiesel blends for energy generation in order to reduce air and noise pollution. Mustard biodiesel (MB) was produced from waste mustard oil and the physicochemical properties were investigated. MB showed a superior calorific value (40.40 MJ/kg), oxidation stability (16 h), cloud point (5 °C) and pour point (−18 °C) than any other conventional biodiesel. During engine performance tests, 10% and 20% MB blends showed 8–13% higher brake specific fuel consumption and 7–8% less brake power compared to diesel fuel. Engine emissions and noise tests showed 9–12% higher NO, 24–42% lower HC, 19–40% lower CO and 2–7% lower noise emission for MB blends compared to diesel fuel. Additionally, comparable engine performance and emission characteristics were found for 10% and 20% MB blends compared to same percentages of palm biodiesels, respectively. In conclusion, 10% and 20% MB blends can be used in diesel engines without modifications.
[Show abstract][Hide abstract] ABSTRACT: This paper presents the fuzzy logic expert system (FLES) for heat transfer performance investigation in helically coiled heat exchanger with spirally corrugated wall operated with water and CuO/water nanofluids. Compared with traditional logic model, fuzzy logic is more efficient in connecting the multiple units to a single output and is invaluable supplements to classical hard computing techniques. Hence, the main objective of this analysis is to investigate the relationship between heat exchanger working parameters and performance characteristics, and to determine how fuzzy logic expert system plays a significant role in prediction of heat transfer performance. Analytical values are taken in helically coiled heat exchanger with spirally corrugated wall operated with water and CuO/water nanofluids for investigation of heat transfer performance. The heat transfer coefficients of CuO/water nanofluids significantly increased about 5.90–14.24% with the increase of volume concentrations compared to water and while the values of the friction factor decreased with the increase in volume flow rate and volume concentration by using nanofluid instead of water. A fuzzy logic expert system model has developed for the prediction of heat transfer coefficient and friction factor. Verification of the developed fuzzy logic model was carried out through various numerical error criteria. For all parameters, the relative error of predicted values are found to be less than and/or slightly above the acceptable limit (5%). The goodnesses of fit of the prediction values from the fuzzy logic expert system model are found to be close to 1.0 as expected, and hence demonstrated the good performance of the developed system.
[Show abstract][Hide abstract] ABSTRACT: Zero-emission fuel cell driven systems are regarded as promising technological advances in the future of the transportation industry that have the potential to replace internal combustion engines. The design, performance, and efficiency properties of a vehicle are often stated to be some of the key challenges in its commercialization. This paper highlights a polymer electrolyte membrane fuel cell (PEMFC)-powered system of an electric bicycle. The system consists of a 250-W fuel cell, ECU, battery pack, DC/DC converter, electric motor, and other supporting equipment. After introducing the different parts of the bicycle, its overall efficiency will be discussed in great detail. The efficiency of fuel cells is not specific; it is a subordinate to the power density where the system operates. Experimental work has been conducted to measure the values of the efficiency and energy flow. The results indicated a maximum fuel cell efficiency of 63% and an overall system efficiency of 35.4%. The latter value is expressed with regards to the Lower Heating Value (LHV) of hydrogen. All measurements were taken for the cruising conditions of the vehicle and its corresponding to power consumption. The results are superior to those of a standard internal ignition engine. The fuel cell performance is least efficient when functioning under maximum output power conditions.
International Journal of Hydrogen Energy 08/2014; 39(25):13276–13284.
[Show abstract][Hide abstract] ABSTRACT: In recent years, palm and jatropha biodiesels have been considered as potential renewable energy sources in Malaysia. Therefore, this experimental investigation was conducted to improve the blend of these two biodiesels (20% biodiesel blend, named P20 and J20, respectively) with the help of oxygenated additives. The comparative improvement of P20 and J20 blends with ethanol, n-butanol, or diethyl ether as additives was evaluated in terms of performance and emissions characteristics of a four-stroke single cylinder diesel engine. The final blend consisted of 80% diesel, 15% biodiesel, and 5% additive. Tests were conducted at different speeds (1200–2400 rpm) at constant full load conditions. Use of additives significantly improved brake power and brake thermal efficiency (BTE). Compared with P20 blend, the use of diethyl ether as additive increased brake power and BTE by about 4.10% and 4.4%, respectively, at 2200 rpm. A similar improvement was observed for J20. The other two additives also improved performance. Although HC emission increased slightly, all blends with additives reduced more NOx and CO emissions than P20 and J20 almost throughout the entire engine test. The use of ethanol as additive reduced CO emission by up to 40%, while the use of diethyl ether as additive reduced NOx emissions by up to 13%. The additives’ oxygen content, volatility, and latent evaporation heat controlled the emissions characteristics of the blends. An analysis of the combustion chamber pressure, temperature and heat release rate of the modified blends revealed interesting features of combustion mechanism, which are indicative of the performance and emissions characteristics. This experiment reveals the potential improvement of palm and jatropha biodiesel blends with the addition of three promising additives.
Energy Conversion and Management 07/2014; 83:149–158.
[Show abstract][Hide abstract] ABSTRACT: The scarcity of fossil fuel has recently been introduced as a major concern to energy policy. This crisis has prompted the search for alternative energy sources. Biodiesel can be considered as one of the potential candidates of energy sources in order to resolve this problem. Most of the fuel properties of biodiesel are very close to that of petroleum diesel. However, commercial use of biodiesel in the automobile engine is being limited because of its unstable fuel properties. Instability of the fuel properties appears to be more aggravated when biodiesel comes in metal contact. The present study is intended to investigate the stability of different fuel properties and chemical composition of palm biodiesel upon exposure to copper and mild steel. Static immersion tests were performed by exposing metallic coupons in palm biodiesel at room temperature for different periods viz., 20, 40, 60 days. Compositional analysis of biodiesel was conducted by gas chromatography. Investigated fuel properties include induction period, total acid value, water content, calorific value, viscosity, density, cloud point, pour point, etc. Effect of biodiesel on metal surfaces was examined by measuring the corrosion rate and conducting SEM/EDS analysis. It is found that copper has strong influence in changing fuel properties especially for viscosity, water content, calorific value, density, etc. Compositional analysis of biodiesel showed that principal unsaturated constituent of palm biodiesel, methyl oleate reduced more in copper exposed biodiesel than that in mild steel exposed biodiesel. Formation of poly unsaturated methyl linoleate was observed in both metal exposed palm biodiesel.
[Show abstract][Hide abstract] ABSTRACT: Nanofluid is one of the novel inventions of science. Nanofluid can be used for energy savings by increasing the heat transfer performance of the heat recovery systems, which are generally struggling to overcome the present challenging issues such as global warming, greenhouse effect, climate change, and fuel crisis. Specific heat capacity is necessary to analyze energy and exergy performances. This paper extant different characteristic of specific heat capacity of nanofluids containing preparation and measuring methods, effects of volume fraction, temperature, types and sizes of nanoparticles and base fluids. Additionally a compilation has been done on available theoretical correlation related to specific heat of nanofluid. Based on existing experimental and theoretical results, nanofluid specific heat falls with the enhancement of volume concentration of nanoparticle though there are some inconsistencies among outcomes. Moreover, specific heat of the nanofluids are generally increased after adding dispersant in the mixtures. However, many contradictory results about the effects of temperatures on specific heat of nanofluids found in the literatures. Therefore, this review will help the researchers and related peoples to get enough information to select a nanofluid based on specific heat for their practical applications.
Renewable and Sustainable Energy Reviews 06/2014; 38:88-98.
[Show abstract][Hide abstract] ABSTRACT: Nanorefrigerants are potential nanofluid that can improve the performance of refrigeration and air-conditioning system. Rheological properties of these fluids need to analyze before practical implementation as they influence the flow characteristics. In the present work, the rheological behavior (relation of shear stress and viscosity with shear rate) of Al2O3/R141b nanorefrigerant for 0.05–0.15 volume concentrations with the temperature ranging from 4 to 16 °C was studied. From this experiment, it is found that, the nanorefrigerant showed non-Newtonian and shear thickening behavior. However, at high shear rates, the trend was found to be quite close to Newtonian behavior. Moreover, viscosity increases with the increase of shear rates and volume concentrations, however, decreases with the increase of temperature.
International Journal of Heat and Mass Transfer 06/2014; 73:118–123.
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