An Experimental Investigation of Early Flame Development in an Optical SI Engine Fueled With Natural Gas

2017 ◽  
Author(s):  
Cosmin E. Dumitrescu ◽  
Vishnu Padmanaban ◽  
Jinlong Liu
Keyword(s):  
Natural Gas ◽  
Flame Propagation ◽  
Turbulent Flame ◽  
The United States ◽  
Si Engine ◽  
Ic Engine ◽  
Piston Bowl ◽  
Pressure Trace ◽  
Flame Development ◽  
Flame Region

Improved internal combustion (IC) engine simulations of natural gas (NG) combustion under conventional and advanced combustion strategies have the potential to increase the use of NG in the transportation sector in the United States. This study focused on the physics of turbulent flame propagation. The experiments were performed in a single-cylinder heavy-duty compression-ignition (CI) optical engine with a bowl-in piston that was converted to spark ignition (SI) NG operation. The size and growth rate of the early flame from the start of combustion until the flame filled the camera field-of-view were correlated to combustion parameters determined from in-cylinder pressure data, under low-speed, lean-mixture, and medium-load conditions. Individual cycles showed evidence of turbulent flame wrinkling, but the cycle-averaged flame edge propagated almost circular in the 2D images recorded from below. More, the flame-speed data suggested a different flame propagation inside a bowl-in piston geometry compared to a typical SI engine chamber. For example, while the flame front propagated very fast inside the piston bowl, the corresponding mass fraction burn was small, which suggested a thick flame region. In addition, combustion images showed flame activity after the end of combustion inferred from the pressure trace. All these findings support the need for further investigations of flame propagation under conditions representative of CI engine geometries, such as those in this study.

An Experimental Investigation of Early Flame Development in an Optical Spark Ignition Engine Fueled With Natural Gas

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Cosmin E. Dumitrescu ◽  
Vishnu Padmanaban ◽  
Jinlong Liu
Keyword(s):  
Natural Gas ◽  
Flame Propagation ◽  
Combustion Engine ◽  
Turbulent Flame ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Piston Bowl ◽  
Pressure Trace ◽  
Flame Development ◽  
Flame Region

Improved internal combustion engine simulations of natural gas (NG) combustion under conventional and advanced combustion strategies have the potential to increase the use of NG in the transportation sector in the U.S. This study focused on the physics of turbulent flame propagation. The experiments were performed in a single-cylinder heavy-duty compression-ignition (CI) optical engine with a bowl-in piston that was converted to spark ignition (SI) NG operation. The size and growth rate of the early flame from the start of combustion (SOC) until the flame filled the camera field-of-view were correlated to combustion parameters determined from in-cylinder pressure data, under low-speed, lean-mixture, and medium-load conditions. Individual cycles showed evidence of turbulent flame wrinkling, but the cycle-averaged flame edge propagated almost circular in the two-dimensional (2D) images recorded from below. More, the flame-speed data suggested different flame propagation inside a bowl-in piston geometry compared to a typical SI engine chamber. For example, while the flame front propagated very fast inside the piston bowl, the corresponding mass fraction burn was small, which suggested a thick flame region. In addition, combustion images showed flame activity after the end of combustion (EOC) inferred from the pressure trace. All these findings support the need for further investigations of flame propagation under conditions representative of CI engine geometries, such as those in this study.

Observation of Flame Propagation in a Heavy-Duty Natural-Gas Lean Burn Spark-Ignition Engine

2019 ◽  
Author(s):  
Jinlong Liu ◽  
Cosmin E. Dumitrescu
Keyword(s):  
Natural Gas ◽  
Flame Propagation ◽  
Low Cost ◽  
Turbulent Flame ◽  
Propagation Speed ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Heavy Duty ◽  
Lean Burn ◽  
Local Flow

Abstract Natural gas (NG) is an alternative combustible fuel for the transportation sectors due to its clean combustion, small carbon footprint, and, with recent breakthroughs in drilling technologies, increased availability and low cost. Currently, NG is better suited for spark-ignited (SI), as a gasoline replacement in conventional SI engines or as a diesel replacement in diesel engines converted to SI operation. However, the knowledge on the fundamentals of NG flame propagation at conditions representative of modern engines (e.g., at higher compression ratios and/or lean mixtures) is limited. Flame propagation inside an engine can be achieved by replacing the original piston with a see-through one. This study visualized flame activities inside the combustion chamber of an optically-accessible heavy-duty diesel engine retrofitted to NG SI operation to increase the understanding of combustion processes inside such converted engines. Recordings of flame luminosity throughout the combustion period at lean-burn operating conditions indicated that the fully-developed turbulent flame formed from several smaller-scale kernels. These small kernels varied with shapes and locations due to different flow motion around the spark location (including the effect of spark electrodes on the local flow separation), different local temperature, or different energy released in these regions. In addition, the turbulent flame was heavily wrinkled during propagation, despite it was grown from a relatively-circular kernel. Moreover, the intake swirl accelerated the flame propagation process while rotating the turbulent flame during its development. Furthermore, the flame propagation speed reduced dramatically when entering the squish region, while the direction from which the flame first touched the bowl edge changed with individual cycles. The results can help the CFD community to better develop RANS and/or LES simulations of such engines under lean-burn operating conditions.

Optical analysis of flame inception and propagation in a lean-burn natural-gas spark-ignition engine with a bowl-in-piston geometry

2019 ◽  
Vol 21 (9) ◽  
pp. 1584-1596 ◽  
Author(s):  
Jinlong Liu ◽  
Cosmin Emil Dumitrescu
Keyword(s):  
Natural Gas ◽  
Flame Propagation ◽  
Diesel Engines ◽  
Pressure Rise ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Expansion Velocity ◽  
Cylinder Pressure ◽  
Lean Burn ◽  
Piston Bowl

Heavy-duty diesel engines can convert to lean-burn natural-gas spark-ignition operation through the addition of a gas injector in the intake manifold and of a spark plug in place of the diesel injector to initiate and control combustion. However, the combustion phenomena in such converted engines usually consist of two distinct stages: a fast-burning stage inside the piston bowl followed by a slow-burning stage inside the squish area. This study used flame luminosity data and in-cylinder pressure measurements to analyze flame propagation inside a bowl-in-piston geometry. The experimental results showed a low coefficient of variation and standard deviation of peak cylinder pressure, moderate rate of pressure rise, and no knocking for the lean-burn (equivalence ratio 0.66), low-speed (900 r/min), and medium-load (6.6 bar IMEP) operating condition. Flame inception had a strong effect on the flame expansion velocity, which increased fast once the flame kernel established, but it reduced near the bowl edge and the entrance of the narrow squish region. However, the burn inside the bowl was very fast. In addition, the long duration of burn inside the squish indicated a much lower flame propagation speed for the outside-the-bowl combustion, which contributed to a long decreasing tail in the apparent heat release rate. Furthermore, cycles with fast flame inception and fast burn inside the bowl had a similar end of combustion with cycles with delayed flame inception and then a retarded burn inside the bowl, which indicated that the combustion inside the squish region determined the combustion duration. Overall, the results suggested that the spark event, the flame development inside the piston bowl, and the start of the second combustion stage affected the phasing and duration of the two combustion stages, which (subsequently) can affect engine efficiency and emissions of diesel engines converted to a lean-burn natural-gas spark-ignition operation.

scholarly journals Simulation Of Natural Gas Combustion Process Using Pressure Based Solver

2016 ◽  
Vol 12 (12) ◽  
pp. 81
Author(s):  
Osama H. Ghazal
Keyword(s):  
Heat Transfer ◽  
Natural Gas ◽  
Fuel Injection ◽  
Combustion Process ◽  
Heat Transfer Process ◽  
Si Engine ◽  
Ic Engine ◽  
Gas Combustion ◽  
Engine Efficiency ◽  
Transfer Models

The aim of this research is to simulate the combustion process for methane using different heat transfer models combined with various fuel injection techniques to better understand the combustion process and heat transfer process inside IC engine which reflect on the engine efficiency. The simulation has been carried out using Lotus Engineering software. This model solves the nonlinear momentum and continuity equations to satisfy the conservation of mass and the conservation of momentum laws. In this analysis a single cylinder four stroke SI engine has been simulated. The fuel used in the simulation is methane. Two fuel systems have been investigated port injection and direct injection. The Wiebe heat release curve has been used. Two widely used for SI engines heat transfer models presented in the simulation, Annand and Woschni. The intension in this paper is to study the effect of various fuel systems and heat transfer models on engine efficiency for different engine speeds. Moreover, the evaluation of the heat transfer models for natural gas SI engine will be tested. Brake power, mean effective pressure, specific fuel consumption, brake thermal efficiency, and heat transfer rate were calculated and discussed to show the effect of varying heat transfer models and fuel systems on engine efficiency.

scholarly journals Emissions Effects of Energy Storage for Frequency Regulation: Comparing Battery and Flywheel Storage to Natural Gas

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 549
Author(s):  
Eric Pareis ◽  
Eric Hittinger
Keyword(s):  
Energy Storage ◽  
Natural Gas ◽  
Fossil Fuels ◽  
Storage Systems ◽  
Storage System ◽  
The United States ◽  
Frequency Regulation ◽  
So2 Emissions ◽  
Gas Generation ◽  
Electrical Generation

With an increase in renewable energy generation in the United States, there is a growing need for more frequency regulation to ensure the stability of the electric grid. Fast ramping natural gas plants are often used for frequency regulation, but this creates emissions associated with the burning of fossil fuels. Energy storage systems (ESSs), such as batteries and flywheels, provide an alternative frequency regulation service. However, the efficiency losses of charging and discharging a storage system cause additional electrical generation requirements and associated emissions. There is not a good understanding of these indirect emissions from charging and discharging ESSs in the literature, with most sources stating that ESSs for frequency regulation have lower emissions, without quantification of these emissions. We created a model to estimate three types of emissions (CO2, NOX, and SO2) from ESSs providing frequency regulation, and compare them to emissions from a natural gas plant providing the same service. When the natural gas plant is credited for the generated electricity, storage systems have 33% to 68% lower CO2 emissions than the gas turbine, depending on the US eGRID subregion, but higher NOX and SO2 emissions. However, different plausible assumptions about the framing of the analysis can make ESSs a worse choice so the true difference depends on the nature of the substitution between storage and natural gas generation.

scholarly journals The Feasibility of Renewable Natural Gas in New Jersey

2021 ◽  
Vol 13 (4) ◽  
pp. 1618
Author(s):  
Anneliese Dyer ◽  
Amelia Christine Miller ◽  
Brianna Chandra ◽  
Juan Galindo Maza ◽  
Carley Tran ◽  
...  
Keyword(s):  
New Jersey ◽  
Natural Gas ◽  
Conceptual Model ◽  
Greenhouse Gas Emission ◽  
Wastewater Treatment Plants ◽  
The United States ◽  
Outreach Program ◽  
Financial Barriers ◽  
The Us ◽  
Renewable Natural Gas

With traditional natural gas being one of the top options for heating in the United States and the present threat of climate change, there is a demand for an alternative clean fuel source. A Renewable Natural Gas Implementation Decision-Making Conceptual Model was created to provide a framework for considering the feasibility of renewable natural gas (RNG) projects and applied to New Jersey, specifically investigating landfills and wastewater treatment plants (WWTPs). Data from the US EPA’s Landfill Methane Outreach Program and New Jersey’s Department of Environmental Protection Sewage Sludge databases were used to identify seven landfills and 22 WWTPs as possible locations for RNG projects. Landfills were found to have a higher potential for producing RNG, on average potentially producing enough RNG to heat 12,792 homes per year versus 1227 for the average WWTP. Additionally, landfills, while having higher capital expenses, have lower projected payback periods, averaging 5.19 years compared to WWTP’s 11.78 years. WWTPs, however, generally are located closer to existing natural gas pipelines than landfills and when they produce more than 362 million standard cubic feet per year (MMSCFY) of biogas are financially feasible. RNG projects at Monmouth County Reclamation Center, Ocean County Landfill, and Passaic Valley Sewerage Commission WWTP show the greatest potential. Greenhouse gas emission reductions from RNG projects at these facilities utilizing all available biogas would be 1.628 million metric tons CO2 equivalents per year, synonymous to removing over 351,000 passenger vehicles from the road each year. In addition, expanding federal and state incentives to encompass RNG as a heating fuel is necessary to reduce financial barriers to RNG projects throughout the US. Overall, this paper supports the hypothesized conceptual model in examining the feasibility of RNG projects through examples from New Jersey and confirms the potential for RNG production utilizing existing waste streams.

scholarly journals Methane Emissions from Process Equipment at Natural Gas Production Sites in the United States: Liquid Unloadings

2014 ◽  
Vol 49 (1) ◽  
pp. 641-648 ◽  
Author(s):  
David T. Allen ◽  
David W. Sullivan ◽  
Daniel Zavala-Araiza ◽  
Adam P. Pacsi ◽  
Matthew Harrison ◽  
...  
Keyword(s):  
United States ◽  
Natural Gas ◽  
The United States ◽  
Methane Emissions ◽  
Gas Production ◽  
Process Equipment ◽  
Natural Gas Production
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