Jeffery Lewis

Bio: Jeffery Lewis is an academic researcher from Georgia Southern University. The author has contributed to research in topic(s): Diesel fuel & Diesel engine. The author has an hindex of 3, co-authored 4 publication(s) receiving 55 citation(s).

Combustion characteristics of a charcoal slurry in a direct injection diesel engine and the impact on the injection system performance.

Abstract: The paper presents the research results pertaining to the renewable biomass charcoal–diesel slurries and their use as alternative fuels for combustion in diesel generating plants. The utilization of charcoal slurry fuel aims to reduce diesel oil consumption and would decrease fossil green house emissions into the atmosphere. The paper investigates the formulation, emulsification, sprays, combustion, injection system operation, and subsequent wear with charcoal–diesel slurries. In the research, cedar wood chips were used for the production of charcoal to be emulsified with diesel oil. The slurry’s viscosity of 27 cP achieved the target (

Experimental and Numerical Investigations on Drag and Torque Characteristics of Three-Bladed Savonius Wind Turbine

Abstract: With the growing demand of energy worldwide, conventional energy is becoming more and more scarce and expensive. The United States is already facing an energy crunch as the fuel price soars. Therefore, there is an obvious need for alternative sources of energy—perhaps more than ever. Wind is among the most popular and fastest-growing forms of electricity generation in the world, which is pollution free and available almost at any time of the day, especially in the coastal regions. The main attraction of the vertical-axis wind turbine is its manufacturing simplicity compared to that of the horizontal-axis wind turbine. Among all different vertical axis wind turbines, Savonius wind turbine is the simplest one. Operation of the Savonius wind turbine is based on the difference of the drag force on its semi-spherical blades, depending on whether the wind is striking the convex or the concave part of the blades. The advantage of this type of wind turbine is its good self-starting and wind directional independence characteristic. It, however, has a relatively lower efficiency in comparison with the lift type vertical-axis wind turbines. Due to its simple design and low construction cost, Savonius rotors are primarily used for water pumping and wind power on a small scale. The main objective of this ongoing research work is to improve the aerodynamic performance of vertical axis Savonius wind turbine. Wind tunnel investigation has been performed on aerodynamic characteristics, such as drag coefficients, and static torque coefficient of three-bladed Savonius rotor model. Also the computational fluid dynamics (CFD) simulation has been performed using FLUENT software to analyze the static rotor aerodynamics such as drag coefficients and torque coefficient, and these results are compared with the corresponding experimental results for verification.Copyright © 2009 by ASME

JP-8 Combustion Characteristics in a Small Diesel Auxiliary Power Unit

Abstract: The US Army Single Fuel Forward policy mandates that deployed vehicles must be operable with aviation fuel JP-8. Therefore, an investigation into the influence of JP-8 on a diesel engine’s performance is currently in progress. The injection, combustion, and performance of JP-8, 20–50% by weight in diesel no.2 mixtures (J20-J50) produced at room temperature were investigated in a 77mm indirect injection, high compression ratio (23.5) diesel engine, in order to evaluate its effectiveness for application in Auxiliary Power Units (APUs) at 2000rpm continuous operation (100% load/BMEP 4.78 bar). Due to the viscosity requirements for proper injection the new fuel can contain as high as 100% JP-8 (J100). The blends had an ignition delay of 1.03ms regardless of the amount of JP-8 introduced. J50 and diesel no.2 exhibited similar characteristics of heat release, the premixed phase being combined with the diffusion combustion. The maximum combustion pressure remained relatively constant for all blends, 72.7bar for diesel and decreased slightly by 0.40bar for J50, with the peak pressure position being delayed by 0.5CAD for the J50. The instantaneous volume-averaged gas combustion temperature reached 2162K for diesel versus 2173K for J50; displaying a 1.2CAD delay in the position of the maximum temperature and retaining the higher temperature for a longer duration for J50. The heat flux in the engine cylinder exhibited comparable maximum values for all blends (diesel: 2.12MW/m2 , J50: 2.14MW/m2 ). The cylinder heat losses were at a minimum during combustion before TDC with increased convection losses at TDC for all fuels and the beginning of the power stroke. The heat losses associated with the system increased slightly with the addition of JP-8. The BSFC for diesel no.2 was 242(g/kW/hr) and increasing by only 0.7% for J50. The engine’s mechanical efficiency displayed similar values for all blends, 83% and decreasing by only 1% for J50. Taking into account each fuels’ corresponding density, the engine’s overall efficiency remained relatively constant at 29% with the addition of the JP-8. The engine investigation demonstrated that up to 50% JP-8 by weight in diesel can be injected and burnt in a small diesel engine with a combustion duration of approximately 5ms, while maintaining the engine overall efficiency. The study validates JP-8 as an excellent source for power generation in a diesel APU based on its combustion characteristics. The next stage of research shall be the full emissions investigation.Copyright © 2011 by ASME

The Influence of Peanut Fatty Acid Methyl Ester Blends on Combustion in an Indirect Injection Diesel Engine

Abstract: The project investigates the effects of peanut FAME on diesel engine combustion and thermal efficiency. The cold flow properties and viscosity were tested and were found that the cloud point (CP) and pour point (PP) of peanut FAME were 17°C and 8°C respectively, and was able to achieve CP of 0°C when blended 20:80 (wt%) with diesel No. 2 (P20). The dynamic viscosity of peanut FAME was 4.2cP (P100) and 2.85cP at 54°C (P20), both fuels are within the ASTM standard for biodiesel. The lower heating value (LHV) of peanut FAME was 37.10MJ/kg (P100) and 41.3MJ/kg (P20) compared to 41.7MJ/kg for diesel No.2 (D100), which supports the usage of peanut FAME in compression ignition engines. At residence time of 5ms from start of injection, P50 has shown positive combustion characteristics with ignition delay of 1.072ms at 2600rpm, 4.78 bmep (100% load). The P50 heat release displayed similar development compared with diesel No. 2, where premixed phase combined with diffusion combustion and reaching a maximum of 20.0J/CAD, which was higher than 17.5J/CAD for D100. Convection flux for both D100 and P50 had values of 1.4MW/m2 . The total heat flux, calculated by Annand model, produced maximum values of 2.1MW/m2 for D100 compared with 2.3MW/m2 for the P50. The mechanical efficiency was only a 4% loss when observing the transition from D100 to P50. These findings support peanut FAME as a viable option when blended and used with diesel engines in order to meet the standards set forth by the RSF-2 and EISA allowing the U.S. to decrease foreign energy dependency and benefiting society through a cleaner burning fuel than is currently in use.Copyright © 2011 by ASME

PFI (port fuel injection) of n-butanol and direct injection of biodiesel to attain LTC (low-temperature combustion) for low-emissions idling in a compression engine

Abstract: In this study, n-butanol (port fuel injection) PFI was investigated in a direct injection compression ignition engine while at idling speeds, and loads, 1–3 bar IMEP (indicated mean effective pressure) in order to determine the effects on combustion, efficiency, emissions, and specifically, a modified tradeoff of soot and nitrogen oxides. As a result, the engine entered into (low-temperature combustion) LTC regions, for selected loads and speeds. Compared with the baseline taken with ultra-low sulfur diesel no. 2, the heat release with n-butanol in (premixed charge compression ignition) PCCI mode, has resulted in a 75% reduction from the maximum values, while a secondary peak appeared where the diffusion combustion typically occurs in the power stroke. At 3 bar IMEP an early, (bottom dead center) BTDC low-temperature heat release was found that began 6° earlier than for the diesel reference cycle, and corresponding to 1200 K. Soot emissions showed a massive decrease of about 98%, concurrently with a 74% reduction of nitrogen oxides at 3 IMEP by controlling the combustion phases and by modifying the classical NOx–soot tradeoff. The results of this work prove that biodiesel combined with n-butanol PFI in PCCI and LTC are very effective in simultaneously reducing soot and NOx at idling speeds.

Review of propulsion systems on LNG carriers

Abstract: Vessel ozone depleting emission regulations are regulated in Annex VI of the MARPOL Convention, wherein the maximum levels of NOx, SOx and suspended particles are established These increasingly strict regulations, together with the increase in natural gas consumption and its price, have conditioned propulsion systems implemented on board vessels This article reviews the different propulsion systems used on board vessels for the transport of Liquefied Natural Gas (LNG) The study describes the main characteristics of the propulsion systems, and the advantages and drawbacks that come along with these, from its very beginnings up to the systems installed to date The described propulsion systems include both gas and steam turbines, combined cycles, 2 and 4 stroke internal combustion engines, as well as reliquefaction plants, while encompassing mechanical, electric and Dual Fuel (DF) technology systems The propulsion systems implemented have undergone continual alteration in order to adjust to market needs, which were always governed by both efficiency and the possibility of consuming boil-off gas (BOG), always in compliance with the strict antipollution regulations in force The current direction of LNG vessel propulsion systems is the installation of 2-stroke DF low pressure engines due to their high efficiency and their possibility of installing a BOG reliquefaction plant Another great advantage of this propulsion system is its compliance with the IMO TIER III emission regulations, without the need to install any supplementary gas treatment system

Effect of process parameters on hydrothermal liquefaction of oil palm biomass for bio-oil production and its life cycle assessment.

Abstract: This paper presents the studies on the effect of three process parameters; temperature, pressure and reaction time on the subcritical and supercritical hydrothermal liquefaction of oil palm empty fruit bunch, palm mesocarp fiber and palm kernel shell. The effect of temperature (330–390 °C), pressure (25–35 MPa) and reaction time (30–240 min) on bio-oil yields were investigated using a Inconel batch reactor. The optimum liquefaction condition for empty fruit bunch, palm mesocarp fiber and palm kernel shell was at supercritical condition of water; 390 °C and 25 MPa. For the effect of reaction time, bio-oil from empty fruit bunch and palm mesocarp fiber attained maximum yields at 120 min, whereas bio-oil yield from palm kernel shell continued to increase at reaction time of 240 min. Lastly, a life cycle assessment based on a conceptual biomass hydrothermal liquefaction process for bio-oil production was constructed and presented.

Organic coal-water fuel: Problems and advances (Review)

Abstract: The study results of ignition of organic coal-water fuel (OCWF) compositions were considered. The main problems associated with investigation of these processes were identified. Historical perspectives of the development of coal-water composite fuel technologies in Russia and worldwide are presented. The advantages of the OCWF use as a power-plant fuel in comparison with the common coal-water fuels (CWF) were emphasized. The factors (component ratio, grinding degree of solid (coal) component, limiting temperature of oxidizer, properties of liquid and solid components, procedure and time of suspension preparation, etc.) affecting inertia and stability of the ignition processes of suspensions based on the products of coaland oil processing (coals of various types and metamorphism degree, filter cakes, waste motor, transformer, and turbine oils, water-oil emulsions, fuel-oil, etc.) were analyzed. The promising directions for the development of modern notions on the OCWF ignition processes were determined. The main reasons limiting active application of the OCWF in power generation were identified. Characteristics of ignition and combustion of coal-water and organic coal-water slurry fuels were compared. The effect of water in the composite coal fuels on the energy characteristics of their ignition and combustion, as well as ecological features of these processes, were elucidated. The current problems associated with pulverization of composite coal fuels in power plants, as well as the effect of characteristics of the pulverization process on the combustion parameters of fuel, were considered. The problems hindering the development of models of ignition and combustion of OCWF were analyzed. It was established that the main one was the lack of reliable experimental data on the processes of heating, evaporation, ignition, and combustion of OCWF droplets. It was concluded that the use of high-speed video recording systems and low-inertia sensors of temperature and gas concentration could help in providing the lacking experimental information.

Influence of injection timing and exhaust gas recirculation of a Calophyllum inophyllum methyl ester fuelled CI engine

Abstract: The present work examines the prospect of using 100% Calophyllum inophyllum methyl ester as a promising alternative fuel for future generation. In this research work, a strategy is developed to reduce NOX emissions of Calophyllum inophyllum biodiesel fuelled diesel engine by varying the injection timing between 21°, 23° and 25° bTDC and by admitting exhaust gas recirculation at the rate of 10%, 20% and 30%. The experiments are conducted in a four stroke diesel engine using 100% Calophyllum inophyllum biodiesel and the engine characteristics are compared with neat diesel engine. Certain important parameters like brake specific energy consumption, brake thermal efficiency, heat release rate, in-cylinder pressure, exhaust emissions including NOX and smoke density are evaluated for various injection timing and EGR rates. Retardation of injection timing to 21° bTDC reduces the NOX emissions very marginally with significant loss in engine performance. It is found that 10% exhaust gas recirculation rate could reduce the NOX emissions more effectively which would meet the proposed Euro V standards. Thus it is observed that exhaust gas recirculation is an effective method to control emissions of 100% Calophyllum inophyllum biodiesel without much compromise in engine efficiency when compared to the influence of injection timing.