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Valentin Soloiu - Georgia Southern University. Statesboro, GA, US

Valentin Soloiu

Allen E. Paulson Distinguished Chair of Renewable Energy and Professor, Department of Mechanical Engineering | Georgia Southern University


Valentin Soloiu is an expert in Renewable and Sustainable, Biofuels Advanced Combustion Technologies, and Heat Transfer and Emissions.





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Dr. Soloiu is the Endowed Chair of Renewable Energy in GSU. Research directions are in renewable and sustainable first and second generation biofuels, with emphasis on new advanced combustion technologies, heat transfer and emissions, spray dynamics, and mixture formation, smart-engine control strategies, and engine tribology. The Biofuels Combustion laboratory has 8 graduate students and 12 undergraduate students working in biofuels research.

Areas of Expertise (3)

Heat Transfer and Emissions

Renewable and Sustainable Biofuels

Advanced Combustion Technologies

Articles (5)

LTC (low-temperature combustion) analysis of PCCI (premixed charge compression ignition) with n-butanol and cotton seed biodiesel versus combustion and emissions characteristics...

Renewable Energy

Valentin Soloiu, Jose D Moncada, Remi Gaubert, Martin Muiños, Spencer Harp, Marcel Ilie, Andrew Zdanowicz, Gustavo Molina

2018 Direct injection (DI) of cotton seed biodiesel (CS100) with port fuel injection (PFI) of n-butanol was used for producing Premixed Controlled Compression Ignition (PCCI) to achieve low-temperature combustion (LTC) and obtain lower gaseous emissions in comparison to ULSD#2 (ultra-low sulfur diesel). PFI engine operation was compared to the combustion of binary mixtures of the same fuels reflecting the same weight ratio of high reactivity (CS100) and low reactivity (n-butanol) fuels. The supercharged engine was operated at constant speed and load with 20% exhaust gas recirculation (EGR). When compared to ULSD#2 reference, the ignition delay of 50% n-butanol and 50% CS100 binary mixture increased by 12% while the 50% n-butanol PFI with 50% CS100 DI led to a 17% decrease in ignition delay. Emissions of soot and nitrogen oxides were simultaneously improved using the PCCI strategy, reducing by 84% and 17%, respectively, given lower peak in-cylinder temperatures and increased oxygenation of the mixture. Carbon monoxide (CO) and unburned hydrocarbons (UHC) increased by several orders of magnitude as a downside of dual fuel injection; ringing intensity, however, improved, decreasing by 30% when using 50% n-butanol PFI in comparison to the ULSD#2 baseline given a smoother pressure gradients. Energy specific fuel consumption for CS50Bu50 (50% ULSD-50% n-butanol blend) increased by 4.5% compared to ULSD#2. The mechanical efficiencies and the coefficient of variation (COV) of IMEP were maintained at 70% and 2.5% respectively, during PCCI, indicating stable operation with renewable fuels.

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Numerical and Experimental Investigation of Aerodynamic Performance of Vertical-Axis Wind Turbine Models with Various Blade Designs

Journal of Power and Energy Engineering

Mosfequr Rahman, Travis E Salyers, Adel El-Shahat, Marcel Ilie, Mahbub Ahmed, Valentin Soloiu

2018 Due to the importance and advantages of Vertical-axis wind turbines (VAWTs) over traditional horizontal-axis wind turbines (HAWTs), this paper is implemented. Savonius turbines with drag-based rotors are adopted from the two more extensive arrangements of vertical wind turbines because of their advantages. In this paper, six diverse rotor plans with measure up to cleared regions are analyzed with exploratory wind burrow testing and numerical reenactments. These proposed models incorporate a conventional Savonius with two different edges criteria and 90 degree helical bend models with two, three and four sharp edges. The models were designed using SolidWorks software then the physical models were 3D printed for testing. A subsonic open-sort wind burrow was utilized for Revolution per Minute (RPM) and torque estimation over a scope of wind speeds. ANSYS Fluent reenactments were utilized for dissecting streamlined execution by using moving reference outline and sliding lattice display methods. A 3-dimensional and transient strategy was utilized for precisely tackling torque and power coefficients. The five new rotor geometries have important advantages such as making a focal point of weight advance from the hub of revolution and causing more noteworthy torque on the turbine shaft contrasted with the customary Savonius turbine. Our new models with the names of CC model and QM model display cross-areas lessen the aggregate scope of negative torque on the edges by 20 degrees, contrasted with the customary Savonius demonstrate. Helical plans are better spread the connected torque over a total transformation resulting in positive torque over every single operational point. Moreover, helical models with 2 and 3 cutting edges have the best self-starting ability in low wind speeds. Helical VAWT with 3 edges starts revolution of 35 RPM at only 1.4 m/s wind speed under no generator stacking. The most noteworthy power coefficient is accomplished, both tentatively and numerically, by the helical VAWT with 2 sharp edges.

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Free Convection Heat Transfer From Sierpinski Carpet Fractal Fins of Varying Size

ASME 2017 International Mechanical Engineering Congress and Exposition

David Calamas, Daniel Dannelley, Jennifer Shaffer, Valentin Soloiu

2017 This works experimentally investigates the thermal performance of extended surfaces inspired by the first four fractal iterations of the Sierpinski carpet fractal pattern in a free convection environment. Fractal fins inspired by the Sierpinski carpet fractal pattern can result in an increase in surface area for convective heat transfer coupled with a simultaneous decrease in mass and are thus desirable in aerospace applications. The thermal performance of the Sierpinski carpet fractal fins was quantified based on fin efficiency, fin effectiveness, and perforated fin effectiveness. When compared with a solid rectangular fin, without perforations, and of an equal base area and package volume a fin inspired by the fourth iteration of the Sierpinski carpet fractal pattern was found to be more effective at dissipating heat by convection. The impact of fin size on the thermal performance of the fractal fins was investigated for a range of power inputs applied at the base (2.5 W, 5 W, and 10 W). A 5.08 cm × 5.08 cm (2 in × 2 in × 1/16 in) fractal fin inspired by the fourth iteration of the Sierpinski carpet fractal was found to have a convective effectiveness, convective efficiency, and convective effectiveness per unit mass, 10.91% more, 10.31% less, and 77.65% more, than a traditional solid (non-perforated) rectangular fin of equal height, width, and thickness. Similarly, a 10.16 cm × 10.16 cm (4 in × 4 in × 1/8 in) fin inspired by the fourth fractal iteration was found to have a convective effectiveness, convective efficiency, and convective effectiveness per unit mass, 3.97% more, 15.91% less, and 66.54% more, than a traditional solid (non-perforated) rectangular fin of equal height, width, and thickness. Thus, the thermal performance of the fractal fins increased as the size of the fins decreased. Regardless of size, the contribution of thermal radiation was significant (often greater than 50%) and should not be neglected. In general, for a fin with a uniform cross-section, intersurface thermal radiation accounts for a significant percentage of thermal radiation heat transfer, particularly as the size of the perforations decreases.

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Combustion and Emissions of Jet-A and N-Butanol in RCCI Operation

ASME 2017 Internal Combustion Engine Division Fall Technical Conference

Valentin Soloiu, Jose Moncada, Remi Gaubert, Spencer Harp, Kyle Flowers, Marcel Ilie

2017 Jet-A was investigated in RCCI (Reactivity Controlled Compression Ignition) given that the fuel is readily available and has a similar cetane number compared to ultra-low sulfur diesel (ULSD#2). To promote emissions’ control, RCCI was conducted with direct injection (DI) of Jet-A and PFI (port fuel injection) of n-butanol. Combustion and emission characteristics of Jet-A RCCI were investigated for a medium duty DI experimental engine operated at constant boost and 30% EGR rate and compared to ULSD#2 RCCI and single-fuel ULSD#2 operation. DI fuel was injected at 5 CAD ATDC and constant rail pressure of 1500 bar. A 20% pilot by mass was added and investigated at timings from 15 to 5 CAD BTDC for combustion stability. The results showed that the effect of the pilot injection on Jet-A combustion was not as prominent as compared to that of ULSD#2, suggesting a slightly different spray and mixture formation. Ignition delay for Jet-A was 15–20% shorter compared to ULSD#2 in RCCI. When the pilot was set to 5 CAD BTDC, CA50 phased for ULSD#2 RCCI by 3 CAD later when compared to Jet-A RCCI. After TDC, the local pressure maximum for ULSD#2 RCCI decreased by 3 bar, resulting from a 15% difference in peak heat release rate between ULSD#2 and Jet-A in RCCI at the same pilot timing. NOx and soot levels were reduced by a respective maximum of 35% and 80% simultaneously in Jet-A RCCI mode compared to single-fuel ULSD#2, yet, were higher compared to ULSD#2 RCCI. Ringing intensity was maintained at similar levels and energy specific fuel consumption (ESFC) improved by at least 15% for Jet-A compared to ULSD#2 in RCCI. Mechanical efficiencies additionally improved at earlier pilot timing by 2%. In summary, Jet-A RCCI allowed for emissions control and increased fuel efficiencies compared to single fuel ULSD#2, however, injection should be further tweaked in order to reach lower soot levels.

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Partially Premixed Compression Ignition of Fischer Tropsch Synthetic Paraffinic Kerosene (S8) With PFI of N-Butanol

ASME 2017 Internal Combustion Engine Division Fall Technical Conference

Valentin Soloiu, Remi Gaubert, Jose Moncada, Spencer Harp, Kyle Flowers, Marcel Ilie

2017 The combustion in an experimental medium duty direct injected engine was investigated in a dual mode process known as partially premixed compression ignition (PPCI). Both a common rail fuel injection system and port fuel injection (PFI) system have been custom designed and developed for the experimental single cylinder engine in order to research the combustion and emissions characteristics of Fischer Tropsch synthetic paraffinic kerosene (S8) with PFI of n-butanol in a low temperature combustion mode (LTC). Baseline results in single fuel (ULSD) combustion were compared to dual fuel strategies coupling both the low and high reactivity fuels. The low reactivity fuel, n-butanol, was port fuel injected in the intake manifold at a constant 30% fuel mass and direct injection of a high reactivity fuel initiated the combustion. The high reactivity fuels are ULSD and a gas to liquid fuel (GTL/S8). Research has been conducted at a constant speed of 1500 RPM at swept experimental engine loads from 3.8 bar to 5.8 bar indicated mean effective pressure (IMEP). Boost pressure and exhaust gas recirculation (EGR) were added at constant levels of 3 psi and 30% respectively. Dual fuel combustion with GTL advanced ignition timing due to the high auto ignition quality and volatility of the fuel. Low temperature heat release (LTHR) was also experienced for each dual-fuel injection strategy prior to the injection of the high reactivity fuel. Peak in-cylinder gas temperatures were similar for each fueling strategy, maintaining peak temperatures below 1400°C. Combustion duration increased slightly in ULSD-PPCI compared to single fuel combustion due to the low reactivity of n-butanol and was further extended with GTL-PPCI from early ignition timing and less premixing. The effect of the combustion duration and ignition delay increased soot levels for dual fuel GTL compared to dual fuel ULSD at 5.8 bar IMEP where the combustion duration is the longest. NOx levels were lowest for GTL-PPCI at each load, with up to a 70% reduction compared to ULSD-PPCI. Combustion efficiencies were also reduced for dual fuel combustion, however the atomization quality of GTL compared to ULSD increased combustion efficiency to reach that of single fuel combustion at 5.8 bar IMEP.

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