Numerical Simulation and Experiments of Reformed Fuel Blends in a Lean-Burn Spark-Ignited Engine

2004 ◽  
Author(s):  
Scott B. Fiveland ◽  
Brett M. Bailey ◽  
Martin L. Willi ◽  
Joel D. Hiltner ◽  
Farzan Parsinejad ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Laminar Flame ◽  
Turbulent Flame ◽  
Chemical Properties ◽  
Fuel Mixture ◽  
Lean Burn ◽  
Fuel Blend ◽  
Engine Simulation ◽  
Fuel Blends ◽  
Detonation Limits

Premixed, lean burn combustion research has focused for years on extending the lean flammability limit while maintaining both stables ignition and turbulent flame propagation. Operating with a leaner air-fuel mixture results in a lower temperature conversion of reactants to products (i.e. reduced NOx) while maintaining thermal efficiency. The lean limit, at some level, is dependent on both the fuel transport and chemical properties. This work sets out to numerically explore the effect of reformed fuels on both fundamental flame stability and the performance/emissions tradeoffs of the engine. The numerical simulations were conducted for a range of reformed fuel blends (10–40%) as well as mixture equivalence ratios (0.35–0.6). The laminar flame speed results clearly define the regime of stable flame propagations for equivalence ratio/reformed fuel blend combinations. Subsequently, a validated and predictive quasi-dimensional engine simulation is used to simulate the performance/emissions characteristics of the complete engine system operating on the reformed fuel blends (10–50%) for a range of ignition timings, and air-fuel ratios. The performance trends define not only the misfire and detonation limits associated with the air-fuel blends but also the thermal efficiency/NOx tradeoffs.

Reformed Fuel and Its Properties, Burning Speeds and Flame Characteristics

2005 ◽  
Author(s):  
Farzan Parsinejad ◽  
Edwin Shirk ◽  
Hameed Metghalchi
Keyword(s):  
Flame Propagation ◽  
Turbulent Flame ◽  
Flame Structure ◽  
Chemical Kinetic ◽  
Cylindrical Vessel ◽  
Flammability Limit ◽  
Lean Burn ◽  
Fuel Blend ◽  
Fuel Blends ◽  
Stable Flame

Premixed, lean burn combustion research has been focused for years on extending the lean flammability limit while maintaining both stable ignition and turbulent flame propagation. Burning speed is a fundamental physicochemical property of homogenous fuel/oxygen/diluent mixtures. It determines the rate of energy released during combustion and is of basic importance for developing and testing chemical kinetic models of hydrocarbons. The burning speed and flame structure of blends of reformed fuel and Methane-air mixtures have been studied using two similar constant volumes; a cylindrical vessel with end windows and a spherical chamber. The Experiments were conducted for a range of reformed fuel blends (20–80%) as well as mixture equivalence ratios (0.4–0.6). The burning speed results clearly define the regime of stable flame propagation for equivalence ratio/reformed fuel blend combinations.

Simulation-Aided Development of Prechamber Ignition System for a Lean-Burn Gasoline Direct Injection Motor-Sport Engine

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Muhammed Fayaz Palakunnummal ◽  
Priyadarshi Sahu ◽  
Mark Ellis ◽  
Marouan Nazha
Keyword(s):  
Thermal Efficiency ◽  
Direct Injection ◽  
Fuel Mixture ◽  
Gasoline Direct Injection ◽  
Lean Burn ◽  
Ignition System ◽  
Motor Sport ◽  
Auto Ignition ◽  
Computational Fluid Dynamics Cfd ◽  
Sport Events

Abstract Due to recent regulation changes to restricted fuel usage in various motor-sport events, motor-sport engine manufacturers have started to focus on improving the thermal efficiency and often claim thermal efficiency figures well above equivalent road car engines. With limited fuel allowance, motor-sport engines are operated with a lean air–fuel mixture to benefit from higher cycle efficiency, requiring an ignition system that is suitable for the lean mixture. Prechamber ignition is identified as a promising method to improve lean limit and has the potential to reduce end gas auto-ignition. This paper analyses the full-load performance of a motor-sport lean-burn gasoline direct injection (GDI) engine and a passive prechamber is developed with the aid of a computational fluid dynamics (CFD) tool. The finalized prechamber design benefited in a significant reduction in burn duration, reduced cyclic variation, knock limit extension, and higher performance.

scholarly journals An Experimental Investigation to Use the Biodiesel Resulting from Recycled Sunflower Oil, and Sunflower Oil with Palm Oil as Fuels for Aviation Turbo-Engines

2021 ◽  
Vol 18 (10) ◽  
pp. 5189
Author(s):  
Grigore Cican ◽  
Marius Deaconu ◽  
Radu Mirea ◽  
Laurentiu Constantin Ceatra ◽  
Mihaiella Cretu
Keyword(s):  
Palm Oil ◽  
Sunflower Oil ◽  
Freezing Point ◽  
Chemical Properties ◽  
Experimental Tests ◽  
Fuel Blend ◽  
Fuel Blends ◽  
Fuel Mixtures ◽  
Calorific Power ◽  
Turbo Engine

The paper is presenting the experimental analysis of the use of biodiesel from waste sunflower oil and a blend of sunflower oil with palm oil as fuel for aviation turbo-engines. A comparative analysis for fuel mixtures made of Jet A + 5% Aeroshell 500 Oil (Ke) with 10%, 30%, and 50% for each bio-fuel type has been performed and Ke has been used as reference. Firstly, the following physical and chemical properties were determined: density, viscosity, flash point, freezing point, calorific power. Then, elemental analysis and Fourier transform infrared spectroscopy (FTIR) analysis were conducted for Ke, biodiesel obtained from recycled sunflower oil (SF), biodiesel obtained from blending recycled sunflower oil, and recycled palm oil (SFP), and for each fuel blend. Secondly, experimental tests of the blends have been conducted on the Jet Cat P80® micro-turbo engine (Gunt Hamburg, Barsbüttel, Germany). The tests have been conducted at different engine working regimes as follows: idle, cruise, intermediate, and maximum. For each regime, a one-minute testing period was chosen, and the engine parameters have been monitored. The turbo engine instrumentation recorded the temperature after the compressor and before the turbine, the fuel consumption and air flow, pressure inside the combustion chamber, and generated thrust. The burning efficiency and the specific consumption have been calculated for all four above-mentioned regimes and for all fuel blends. Two accelerometers have been installed on the engine’s support to register radial and axial vibrations allowing the assessment of engine stability.

Flame Extinction Limits of H2‐CO Fuel Blends

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Ahsan R. Choudhuri ◽  
Mahesh Subramanya ◽  
Subramanyam R. Gollahalli
Keyword(s):  
Laminar Flame ◽  
Critical Value ◽  
Mean Value ◽  
Flame Velocity ◽  
Flame Extinction ◽  
Hydrogen Fuel ◽  
Fuel Blend ◽  
Fuel Blends ◽  
Extinction Limit ◽  
The Mean

The flame extinction limits of syngas (H2‐CO) flames were measured using a twin-flame counterflow burner. Plots of extinction limits (%f: volumetric percent of fuel in air) versus global stretch rates were generated at different fuel blend compositions and were extrapolated to determine the flame extinction limit corresponding to an experimentally unattainable zero-stretch condition. The zero-stretch extinction limit of H2‐CO mixtures decreases with the increase in H2 concentration in the mixture. The average difference between the measured flame extinction limit and the Le Chatelier’s calculation is around 7% of the mean value. The measured OH chemiluminescence data indicates that regardless of blend composition the OH radical concentration reduces to a critical value prior to the flame extinction. The measured laminar flame velocity close to the extinction indicates that regardless of fuel composition, the premixed flame of hydrogen fuel blends extinguishes when the mixture laminar flame velocity falls below a critical value.

scholarly journals Numerical Investigation of a Central Fuel Property Hypothesis Under Boosted Spark-Ignition Conditions

2019 ◽  
Author(s):  
Pinaki Pal ◽  
Krishna Kalvakala ◽  
Yunchao Wu ◽  
Matthew McNenly ◽  
Simon Lapointe ◽  
...  
Keyword(s):  
Octane Number ◽  
Laminar Flame ◽  
Turbulent Flame ◽  
Spark Ignition ◽  
Flame Speed ◽  
Operating Conditions ◽  
Fuel Properties ◽  
Laminar Flame Speed ◽  
Fuel Blend ◽  
Fuel Property

Abstract In the present work, a central fuel property hypothesis (CFPH), which states that fuel properties are sufficient to provide an indication of a fuel’s performance irrespective of its chemical composition, was numerically investigated. In particular, the objective of the study was to determine whether Research Octane Number (RON) and Motor Octane Number (MON), as fuel properties, are sufficient to describe a fuel’s knock-limited performance under boosted spark-ignition (SI) conditions within the framework of CFPH. To this end, four TPRF-bioblendstock surrogates having different compositions but matched RON (= 98) and MON (= 90), were first generated using a non-linear regression model based on artificial neural network (ANN). Three unconventional bioblendstocks were included in the analysis: Di-isobutylene (DIB), Isobutanol and Anisole. Skeletal reaction mechanisms were generated for the TPRF-DIB, TPRF-isobutanol and TPRF-anisole blends from a detailed kinetic mechanism. Thereafter, numerical simulations were performed for the fuel surrogates using the skeletal mechanisms and a virtual cooperative fuel research (CFR) engine model, under a representative boosted operating condition. In the computational fluid dynamics (CFD) model, the G-equation approach was employed to track the turbulent flame front and the well-stirred reactor model combined with multi-zone binning strategy was used to capture auto-ignition in the end-gas. In addition, laminar flame speed was tabulated for each blend as a function of pressure, temperature and equivalence ratio a priori, and the lookup tables were used to prescribe laminar flame speed as an input to the G-equation model. Parametric spark timing sweeps were performed for each fuel blend to determine the corresponding knock-limited spark advance (KLSA) and 50% burn point (CA50) at the respective KLSA timing. It was observed that despite same RON, MON and engine operating conditions, the TPRF-Anisole blend exhibited markedly different knock-limited performance from the other three blends. This deviation from the octane index (OI) expectation was shown to be caused by differences in laminar flame speed (LFS). However, it was found that relatively large fuel-specific differences in LFS (> 20%) would have to be present to cause any appreciable deviation from the OI framework. Otherwise, RON and MON would still be robust enough to predict a fuel’s knock-limited performance.

scholarly journals Numerical Investigation of a Central Fuel Property Hypothesis Under Boosted Spark-Ignition Conditions

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Pinaki Pal ◽  
Krishna Kalvakala ◽  
Yunchao Wu ◽  
Matthew McNenly ◽  
Simon Lapointe ◽  
...  
Keyword(s):  
Octane Number ◽  
Laminar Flame ◽  
Turbulent Flame ◽  
Spark Ignition ◽  
Flame Speed ◽  
Operating Conditions ◽  
Fuel Properties ◽  
Laminar Flame Speed ◽  
Fuel Blend ◽  
Fuel Property

Abstract In the present work, a central fuel property hypothesis (CFPH), which states that fuel properties are sufficient to provide an indication of a fuel’s performance irrespective of its chemical composition, was numerically investigated. In particular, the objective of the study was to determine whether Research Octane Number (RON) and Motor Octane Number (MON), as fuel properties, are sufficient to describe a fuel’s knock-limited performance under boosted spark-ignition (SI) conditions within the framework of CFPH. To this end, four TPRF-bioblendstock surrogates having different compositions but matched RON (=98) and MON (=90), were first generated using a non-linear regression model based on artificial neural network (ANN). Three unconventional bioblendstocks were included in the analysis: di-isobutylene (DIB), isobutanol, and Anisole. Skeletal reaction mechanisms were generated for the TPRF-DIB, TPRF-isobutanol, and TPRF-anisole blends from a detailed kinetic mechanism. Thereafter, numerical simulations were performed for the fuel surrogates using the skeletal mechanisms and a virtual cooperative fuel research (CFR) engine model, under a representative boosted operating condition. In the computational fluid dynamics (CFD) model, the G-equation approach was employed to track the turbulent flame front and the well-stirred reactor model combined with the multi-zone binning strategy was used to capture auto-ignition in the end-gas. In addition, laminar flame speed (LFS) was tabulated for each blend as a function of pressure, temperature, and equivalence ratio a priori, and the lookup tables were used to prescribe laminar flame speed as an input to the G-equation model. Parametric spark timing sweeps were performed for each fuel blend to determine the corresponding knock-limited spark advance (KLSA) and 50% burn point (CA50) at the respective KLSA timing. It was observed that despite same RON, MON, and engine operating conditions, the TPRF-anisole blend exhibited markedly different knock-limited performance from the other three blends. This deviation from the octane index (OI) expectation was shown to be caused by differences in laminar flame speed. However, it was found that relatively large fuel-specific differences in LFS (>20%) would have to be present to cause any appreciable deviation from the OI framework. Otherwise, RON and MON would still be robust enough to predict a fuel’s knock-limited performance.

Correlations for Turbulent Flame Speed of Different Syngas Mixtures at High Pressure and Temperature

2012 ◽  
Author(s):  
S. Daniele ◽  
P. Jansohn
Keyword(s):  
High Pressure ◽  
Laminar Flame ◽  
Turbulent Flame ◽  
Fuel Mixture ◽  
Turbulent Flames ◽  
Flame Speed ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Turbulent Flame Speed ◽  
Combustion Properties

There is an obvious lack of data and understanding of the behavior of turbulent flames at high temperature and high pressure, especially concerning hydrogen containing fuels. Among the many relevant parameters, the turbulent flame speed “ST” is one of the most interesting for scientists and engineers. This paper reports an experimental investigation of premixed syngas combustion at gas-turbine like conditions, with emphasis on the determination of ST/SL derived as global fuel consumption per unit time. Experiments at pressures up to 2.00 MPa, inlet temperatures and velocities up to 773K and 150 m/s respectively, u′/SL greater than 100 are presented. Comparison between different syngas mixtures and methane clearly show much higher ST/SL for the former fuel. It is shown that ST/SL is strongly dependent on preferential diffusive-thermal (PDT) effects, co-acting with hydrodynamic effects, even for very high u′/SL. ST/SL increases with rising hydrogen content in the fuel mixture and with pressure. A correlation for ST/SL valid for all investigated fuel mixtures, including methane, is proposed in terms of turbulence properties (turbulence intensity and integral length scale), combustion properties (laminar flame speed and laminar flame thickness) and operating conditions (pressure and inlet temperature). The correlation captures effects of preferential diffusive-thermal and hydrodynamic instabilities.

scholarly journals A Comparison of Ethanol, Methanol, and Butanol Blending with Gasoline and Its Effect on Engine Performance and Emissions Using Engine Simulation

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1322
Author(s):  
Simeon Iliev
Keyword(s):  
Alternative Fuels ◽  
Fossil Fuels ◽  
Gasoline Engine ◽  
Engine Performance ◽  
Exhaust Emissions ◽  
Engine Simulation ◽  
Engine Model ◽  
Fuel Blends ◽  
Performance And Emissions ◽  
Blended Fuels

Air pollution, especially in large cities around the world, is associated with serious problems both with people’s health and the environment. Over the past few years, there has been a particularly intensive demand for alternatives to fossil fuels, because when they are burned, substances that pollute the environment are released. In addition to the smoke from fuels burned for heating and harmful emissions that industrial installations release, the exhaust emissions of vehicles create a large share of the fossil fuel pollution. Alternative fuels, known as non-conventional and advanced fuels, are derived from resources other than fossil fuels. Because alcoholic fuels have several physical and propellant properties similar to those of gasoline, they can be considered as one of the alternative fuels. Alcoholic fuels or alcohol-blended fuels may be used in gasoline engines to reduce exhaust emissions. This study aimed to develop a gasoline engine model to predict the influence of different types of alcohol-blended fuels on performance and emissions. For the purpose of this study, the AVL Boost software was used to analyse characteristics of the gasoline engine when operating with different mixtures of ethanol, methanol, butanol, and gasoline (by volume). Results obtained from different fuel blends showed that when alcohol blends were used, brake power decreased and the brake specific fuel consumption increased compared to when using gasoline, and CO and HC concentrations decreased as the fuel blends percentage increased.

Engine performance and emission characteristics of a compression ignition engine fuelled with diesel/dimethoxymethane blends

2005 ◽  
Vol 219 (7) ◽  
pp. 905-914 ◽  
Author(s):  
Y Ren ◽  
Z H Huang ◽  
D M Jiang ◽  
L X Liu ◽  
K Zeng ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Mass Fraction ◽  
Volume Fraction ◽  
Engine Performance ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Performance And Emission ◽  
Fuel Blends ◽  
Performance And Emissions ◽  
Combustion Phase

The performance and emissions of a compression ignition engine fuelled with diesel/dimethoxymethane (DMM) blends were studied. The results showed that the engine's thermal efficiency increased and the diesel equivalent brake specific fuel consumption (b.s.f.c.) decreased as the oxygen mass fraction (or DMM mass fraction) of the diesel/DMM blends increased. This change in the diesel/DMM blends was caused by an increased fraction of the premixed combustion phase, an oxygen enrichment, and an improvement in the diffusive combustion phase. A remarkable reduction in the exhaust CO and smoke can be achieved when operating on the diesel/DMM blend. Flat NO x/smoke and thermal efficiency/smoke curves are presented when operating on the diesel/DMM fuel blends, and a simultaneous reduction in both NO x and smoke can be realized at large DMM addition. Thermal efficiency and NO x give the highest value at 2 per cent oxygen mass fraction (or 5 per cent DMM volume fraction) for the combustion of diesel/DMM blends.

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