Computational Modeling of Natural Gas Injection in a Large Bore Engine

2004 ◽  
Vol 126 (3) ◽  
pp. 656-664 ◽  
Author(s):  
Gi-Heon Kim ◽  
Allan Kirkpatrick ◽  
Charles Mitchell
Keyword(s):  
High Pressure ◽  
Computational Modeling ◽  
Gas Flow ◽  
High Pressures ◽  
Volume Fraction ◽  
Gas Injection ◽  
Cylinder Wall ◽  
Poppet Valve ◽  
Injection Process ◽  
Planar Laser

The topic of this paper is the computational modeling of gas injection through various poppet valve geometries in a large bore engine. The objective of the paper is to contribute to a better understanding of the significance of the poppet valve and the piston top in controlling the mixing of the injected fuel with the air in the cylinder. In this paper, the flow past the poppet valve into the engine cylinder is computed for both a low (4 bar) and a high pressure (35 bar) injection process using unshrouded and shrouded valves. Experiments using PLIF (planar laser induced fluorescence) are used to visualize the actual fluid flow for the valve geometries considered. The results indicate that for low injection pressures the gas flow around a typical poppet valve collapses to the axis of symmetry of the valve downstream of the poppet. At high pressure, the gas flow from this simple poppet valve does not collapse, but rather expands outward and flows along the cylinder wall. At high pressures, addition of a shroud around the poppet valve was effective in directing the supersonic flow toward the center of the cylinder. Additional computations with a moving piston show that at top dead center, the flammable volume fraction and turbulence intensity with high pressure shrouded injection are larger than for low pressure injection.

Computational Modeling of Natural Gas Injection in a Large Bore Engine

2002 ◽  
Author(s):  
Gi-Heon Kim ◽  
Allan Kirkpatrick ◽  
Charles Mitchell
Keyword(s):  
High Pressure ◽  
Fluid Flow ◽  
Computational Modeling ◽  
Gas Flow ◽  
Gas Injection ◽  
Cylinder Wall ◽  
Poppet Valve ◽  
Injection Process ◽  
Pressure Injection ◽  
Planar Laser

The topic of this paper is the computational modeling and experimental visualization of gas injection in a large bore engine. The injection process is accomplished through the use of a mechanically or electrically controlled poppet valve. The objective of the paper is to more fully understand the significance of the poppet valve and the piston top in controlling the mixing of the injected fuel with the air in the cylinder. In this paper, the flow past the poppet valve into the engine cylinder is computed using computational fluid dynamics (CFD) for both a low (4 bar) and a high pressure (34 bar) injection process using unshrouded and shrouded valves. Flow visualization using planar laser induced fluorescence (PLIF) is used to visualize the actual fluid flow. The results indicate that for low pressures the gas flow around the poppet valve collapses downstream of the poppet. At high pressure, the gas flow does not collapse, but flows along the cylinder wall, producing poor mixing in the cylinder. To obtain satisfactory fluid flow at high pressure, the results indicated a shroud should be employed around the poppet valve to direct the gas into the center of the cylinder. Additional computations show that at top dead center, the flammable mixture and fuel mass fraction for the high-pressure injection are significantly greater than for the low-pressure injection.

scholarly journals Experiments with CO<sub>2</sub>-in-air reference gases in high-pressure aluminum cylinders

2018 ◽  
Vol 11 (10) ◽  
pp. 5565-5586 ◽  
Author(s):  
Michael F. Schibig ◽  
Duane Kitzis ◽  
Pieter P. Tans
Keyword(s):  
High Pressure ◽  
Large Scale ◽  
High Pressures ◽  
Co2 Enrichment ◽  
Low Flow ◽  
Cylinder Wall ◽  
Practical Applications ◽  
Sources And Sinks ◽  
Carbon Dioxide Co2 ◽  
Adsorption Desorption

Abstract. Long-term monitoring of carbon dioxide (CO2) in the atmosphere is key for a better understanding of the processes involved in the carbon cycle that have a major impact on further climate change. Keeping track of large-scale emissions and removals (sources and sinks) of CO2 requires very accurate measurements. They all have to be calibrated very carefully and have to be traceable to a common scale, the World Meteorological Organization (WMO) CO2 X2007 scale, which is maintained by the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL) in Boulder, CO, USA. The international WMO GAW (Global Atmosphere Watch) program sets as compatibility goals for the required agreement between different methods and laboratories ±0.1 µmol mol−1 for the Northern Hemisphere and ±0.05 µmol mol−1 for the Southern Hemisphere. The reference gas mixtures used to pass down and distribute the scale are stored in high-pressure aluminum cylinders. It is crucial that the standards remain stable during their entire time of use. In this study the tested vertically positioned aluminum cylinders showed similar CO2 enrichment during low-flow conditions (0.3 L min−1), which are similar to flows often used for calibration gases in practical applications. The average CO2 enrichment was 0.090±0.009 µmol mol−1 as the cylinder was emptied from about 150 to 1 bar above atmosphere. However, it is important to note that the enrichment is not linear but follows Langmuir's adsorption–desorption model, where the CO2 enrichment is almost negligible at high pressures but much more pronounced at low pressures. When decanted at a higher rate of 5.0 L min−1 the enrichment becomes 0.22±0.05 µmol mol−1 for the same pressure drop. The higher enrichment is related to thermal diffusion and fractionation effects in the cylinder, which were also dependent on the cylinder's orientation and could even turn negative. However, the low amount of CO2 adsorbed on the cylinder wall and the fact that the main increase happens at low pressure lead to the conclusion that aluminum cylinders are suitable to store ambient CO2-in-dry-air mixtures provided they are not used below 20 bar. In cases where they are used in high-flow experiments that involve significant cylinder temperature changes, special attention has to be paid to possible fractionation effects.

Turbine-Compressor Train Uprated for 30% Increase in Gas Flow

1991 ◽  
Author(s):  
C. D. (Charlton) Breon ◽  
D. R. (Daniel) Veth
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Gas Flow ◽  
Gas Injection ◽  
Oil Field ◽  
General Electric ◽  
Prudhoe Bay

A turbine-compressor train consisting of a General Electric MS5001 Model R single-shaft gas turbine, a Philadelphia Gear speed-increasing gearbox, and a Dresser-Clark centrifugal compressor was uprated for 30% increased gas throughput. This train is one of thirteen units operated by ARCO Alaska, Inc. for high pressure natural gas injection service in Alaska’s Prudhoe Bay Oil Field. The uprate included an in-place conversion of the gas turbine from a Model R to a Model P configuration. This paper describes the engineering, planning, and implementation activities that led up to the successful uprate of this train with only a 24 day equipment outage.

scholarly journals Self-Propagating High Temperature Synthesis of MgB2 Superconductor in High-Pressure of Argon Condition

2017 ◽  
Vol 19 (2) ◽  
pp. 177 ◽  
Author(s):  
S. Tolendiuly ◽  
S. M. Fomenko ◽  
G. C. Dannangoda ◽  
K. S. Martirosyan
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
High Pressures ◽  
Volume Fraction ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Ar Gas

<p>Magnesium diboride can be synthesized under argon ambient, elevated or high pressures. High-pressure syntheses are promising methods for manufacturing of the bulk MgB<sub>2</sub> superconductor material. We have been used high pressure of Ar gas in order to investigate its effect on properties of MgB<sub>2</sub> superconductor such as critical temperature and current density. Bulk MgB<sub>2</sub> superconductor was synthesized from elemental Mg–B powders in thermal explosion mode of self-propagating high-temperature synthesis (SHS) under argon pressure of 25 atm. XRD pattern of the as-synthesized product indicates an almost complete conversion of the reactants to the MgB<sub>2</sub> single phase. Most of the diffractions peaks are related to the MgB<sub>2</sub> polycrystalline bulk material. The impurity fraction is less than 24.3% in total sample and identified as MgO and MgB<sub>4</sub> secondary phases. The positive effect of pressure of Ar gas during synthesis of MgB2 on critical current density JC has been confirmed. The critical current density of the sample was achieved in high pressure reactor was 3.8×10<sup>6</sup> A/cm<sup>2</sup>. A superconducting volume fraction of 16% under a magnetic field of 10 Oe was obtained at 5 K, indicating that the superconductivity was bulk in nature. The succeeded level of superconductor parameters of the high-pressure synthesized MgB<sub>2</sub> and the possibility to produce a large bulk products make this technology very promising for practical applications.</p>

A new model for volume fraction measurements of horizontal high-pressure wet gas flow using gamma-based techniques

2018 ◽  
Vol 96 ◽  
pp. 311-320 ◽  
Author(s):  
Yanzhi Pan ◽  
Yugao Ma ◽  
Shanfang Huang ◽  
Pengman Niu ◽  
Dong Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Flow ◽  
Volume Fraction ◽  
New Model ◽  
Wet Gas

Factors Influencing Foam Height in Gas Injection Process for Aluminum Foams

2015 ◽  
Vol 1104 ◽  
pp. 33-37
Author(s):  
Jian Yu Yuan ◽  
Yan Xiang Li ◽  
Xiang Chen ◽  
Yu Tong Zhou
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Foam Stability ◽  
Gas Injection ◽  
Foam Height ◽  
Gas Flow Rate ◽  
Aluminum Foams ◽  
Particle Content ◽  
Injection Process ◽  
Factors Influencing

The present study proposed a convenient method to characterize the stability of aluminum foams by utilizing the resulting foam height. The factors influencing foam height in gas injection process was investigated including the blowing gas (N2 and air), particle content (5vol.%-15vol.%), gas flow rate (0.03m3/h-0.3m3/h) and orifice size (0.3mm and 0.5mm). Factors that contribute to the foam stability including oxygen in the blowing gas and larger particle content in the melt was proved to be positively related to the foam height. Moreover, it was found that larger gas flow rate and smaller orifice size lead to larger foam height. The cell wall microstructure and thickness was also analyzed to better understand the foaming behavior. The present study offers favorable proof that the foam height in the gas injection process can be a good index for the foam stability.

Analytical and Computational Modeling of High Pressure Gas Injection

2001 ◽  
Author(s):  
Allan Kirkpatrick ◽  
Yuan Li ◽  
Charles Mitchell ◽  
Bryan Willson
Keyword(s):  
Computational Modeling ◽  
Method Of Characteristics ◽  
Pressure Ratio ◽  
Gas Injection ◽  
Injection Pressure ◽  
Rarefaction Waves ◽  
Axisymmetric Nozzle ◽  
Injection Process ◽  
Flow Features ◽  
Shock Location

Abstract The topic of this paper is the analytical and computational modeling of the gas injection process in a large bore natural gas fueled engine. At high injection pressures, the overall gas injection and mixing process includes compressible flow features such as rarefaction waves and shock formation. The injection geometries examined in the paper include both a two dimensional slot and an axisymmetric nozzle. The computations examine the effect of the injection pressure/back pressure ratio, with ratios ranging from 3 to 80. The computational modeling was validated by comparison with results obtained from a 2D analytical method of characteristics solution. The validation process evaluated factors such as pressure and Mach number profiles, jet boundary shape and shock location.

Planar Laser Induced Fluorescence Imaging of Gas Injection From Fuel Valves for Large Bore Natural Gas Engines

2001 ◽  
Author(s):  
Daniel B. Olsen ◽  
Dan B. Mastbergen ◽  
Bryan D. Willson
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Fuel Injection ◽  
Gas Injection ◽  
Laser Induced Fluorescence ◽  
Natural Gas Engines ◽  
Pressure Injection ◽  
Fuel Jet ◽  
Planar Laser ◽  
High Pressure Injection

Abstract Investigations of the fuel injection process for large bore natural gas engines are performed on an off-engine test fixture. Two types of fuel injectors are studied, a low pressure (0.39 MPa) and a high pressure (3.5 MPa) gas injection valve. Planar laser induced fluorescence is implemented to image fuel jet concentration. The fuel jet from each injector is imaged from the start of injection though their valve-open duration. Effects of injection pressure, piston interaction, and injection event repeatability are investigated. The results are related to previous engine studies of high pressure fuel injection and Schlieren photography of in-cylinder events on a Cooper-Bessemer GMV large bore natural gas engines. The images indicate that the low pressure valve achieves more effective mixing during jet penetration. The high pressure injection event shows relatively little mixing during jet penetration. However, the high pressure jet has much more energy when it impinges on the piston. It is evident that the important time for mixing using high pressure injection occurs after piston impingement.

CFD Simulation of Enhanced Oil Recovery Using Nanosilica/Supercritical CO2

2015 ◽  
Vol 1104 ◽  
pp. 81-86 ◽  
Author(s):  
Malahat Ghanad Dezfully ◽  
Arezou Jafari ◽  
Reza Gharibshahi
Keyword(s):  
Porous Medium ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Cfd Simulation ◽  
Volume Fraction ◽  
Gas Injection ◽  
Injection Process ◽  
Nanoparticles Concentration ◽  
Volume Method

In this study series of runs were done by a CFD technique in which the injected fluid is nanoparticles/supercritical CO2. Geometry of the porous medium was created with the commercial grid generation tool (Gambit software). Continuity, momentum and volume fraction equations were solved based on the finite volume method. The benefits of existing nanoparticles in the gas injection process have been investigated. The numerical results show that addition of nanosilica into the supercritical CO2improves the oil recovery. It was also found that by increasing the nanoparticles concentration from 1 Vol. % to 2 Vol. %, the oil recovery factor increases about 5%. In addition, obtained results confirmed that by injecting the nanofluid fingers are reduced. The displacing fluid containing nanoparticles is more efficient than the supercritical CO2in sweeping the in-situ oil.

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