Journal articles: 'Large bore gas engine'

1

Schaub, F. S., and R. L. Hubbard. "A Procedure for Calculating Fuel Gas Blend Knock Rating for Large-Bore Gas Engines and Predicting Engine Operation." Journal of Engineering for Gas Turbines and Power 107, no. 4 (October 1, 1985): 922–30. http://dx.doi.org/10.1115/1.3239837.

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This paper describes the procedure developed by Cooper-Bessemer for large-bore gas engines to calculate the knock rating of gas fuel blends and to predict with accuracy the required engine build to use that fuel with optimum detonation margin. Engine prototype test work has included fuel sensitivity tests mapped as a function of compression ratio, fuel air ratio, ignition advance, combustion air temperature, and engine rating. Success in predicting production engine operation for a given application involving a particular fuel blend has been gratifying. The basic reference method blend selected was normal butane in methane. Details are included in the paper to illustrate the problems in making sensitivity correlations between small-bore fuel research engines and large-bore production engines.

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Olsen, D. B., J. C. Holden, G. C. Hutcherson, and B. D. Willson. "Formaldehyde Characterization Utilizing In-Cylinder Sampling in a Large Bore Natural Gas Engine." Journal of Engineering for Gas Turbines and Power 123, no. 3 (December 7, 2000): 669–76. http://dx.doi.org/10.1115/1.1363601.

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This research addresses the growing need to better understand the mechanisms through which engine-out formaldehyde is formed in two-stroke cycle large bore natural gas engines. The investigation is performed using a number of different in-cylinder sampling techniques implemented on a Cooper-Bessemer GMV-4TF four-cylinder two-stroke cycle large bore natural gas engine with a 36-cm (14-in.) bore and a 36-cm (14-in.) stroke. The development and application of various in-cylinder sampling techniques is described. Three different types of valves are utilized, (1) a large sample valve for extracting a significant fraction of the cylinder mass, (2) a fast sample valve for crank angle resolution, and (3) check valves. Formaldehyde in-cylinder sampling data are presented that show formaldehyde mole fractions at different times during the engine cycle and at different locations in the engine cylinder. The test results indicate that the latter part of the expansion process is a critical time for engine-out formaldehyde formation. The data show that significant levels of formaldehyde form during piston and end-gas compression. Additionally, formaldehyde is measured during the combustion process at mole fractions five to ten times higher than engine-out formaldehyde mole fractions. Formaldehyde is nearly completely destroyed during the final part of the combustion process. The test results provide insights that advance the current understanding and help direct future work on formaldehyde formation.

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Mitchell, Charles E., and Daniel B. Olsen. "Formaldehyde Formation in Large Bore Natural Gas Engines Part 1: Formation Mechanisms." Journal of Engineering for Gas Turbines and Power 122, no. 4 (December 29, 1999): 603–10. http://dx.doi.org/10.1115/1.1290585.

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Recent testing of exhaust emissions from large bore natural gas engines has indicated that formaldehyde CH2O is present in amounts that are significant relative to hazardous air pollutant standards. In consequence, a detailed literature review has been carried out at Colorado State University to assess the current state of knowledge about formaldehyde formation mechanisms and evaluate its applicability to gas engines. In this paper the following topics from that review, which bear directly on formaldehyde formation in natural gas engines, are discussed: (1) post combustion equilibrium concentrations; (2) chemical kinetics; (3) flame propagation and structure; (4) partial oxidation possibilities; and (5) potential paths for engine out formaldehyde. Relevant data taken from the literature on equilibrium concentrations and in-flame temperatures and concentrations are presented in graphical form. A map of possible paths for engine out formaldehyde is used to summarize results of the review, and conclusions relative to formation and destruction mechanisms are presented. [S0742-4795(00)00904-2]

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Olsen, Daniel B., and Charles E. Mitchell. "Formaldehyde Formation in Large Bore Engines Part 2: Factors Affecting Measured CH2O." Journal of Engineering for Gas Turbines and Power 122, no. 4 (December 29, 1999): 611–16. http://dx.doi.org/10.1115/1.1290586.

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Current research shows that the only hazardous air pollutant of significance emitted from large bore natural gas engines is formaldehyde CH2O. A literature review on formaldehyde formation is presented focusing on the interpretation of published test data and its applicability to large bore natural gas engines. The relationship of formaldehyde emissions to that of other pollutants is described. Formaldehyde is seen to have a strong correlation to total hydrocarbon (THC) level in the exhaust. It is observed that the ratio of formaldehyde to THC concentration is roughly 1.0–2.5 percent for a very wide range of large bore engines and operating conditions. The impact of engine operating parameters, load, rpm, spark timing, and equivalence ratio, on formaldehyde emissions is also evaluated. [S0742-4795(00)01004-8]

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Olsen, D. B., G. C. Hutcherson, B. D. Willson, and C. E. Mitchell. "Development of the Tracer Gas Method for Large Bore Natural Gas Engines—Part II: Measurement of Scavenging Parameters." Journal of Engineering for Gas Turbines and Power 124, no. 3 (June 19, 2002): 686–94. http://dx.doi.org/10.1115/1.1454117.

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In this work the tracer gas method using nitrous oxide as the tracer gas is implemented on a stationary two-stroke cycle, four-cylinder, fuel-injected large-bore natural gas engine. The engine is manufactured by Cooper-Bessemer, model number GMV-4TF. It is representative of the large bore natural gas stationary engine fleet currently in use by the natural gas industry for natural gas compression and power generation. Trapping efficiency measurements are carried out with the tracer gas method at various engine operating conditions, and used to evaluate the scavenging efficiency and trapped A/F ratio. Scavenging efficiency directly affects engine power and trapped A/F ratio has a dramatic impact on pollutant emissions. Engine operating conditions are altered through variations in boost pressure, speed, back pressure, and intake port restriction.

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Rossegger, Bernhard, Albrecht Leis, Martin Vareka, Michael Engelmayer, and Andreas Wimmer. "Lubricating Oil Consumption Measurement on Large Gas Engines." Lubricants 10, no. 3 (March 8, 2022): 40. http://dx.doi.org/10.3390/lubricants10030040.

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Increasing the reliability of combustion engines while further reducing emissions and life cycle costs are the main drivers for optimizing lubricating oil consumption (LOC). However, in order to reduce the lube oil consumption of an engine, it is crucial to measure it accurately. Therefore, a LOC measurement device based on the use of the stable isotope deuterium has been developed. Previous publications have focused on the use of passenger car engines. This publication describes the first application of this newly developed method on a large gas engine. This is of particular interest as large-bore engines might show different oil consumption behavior, much higher LOC in gram per hour and the bigger oil reservoir need larger amounts of tracer. Additionally, a different type of fuel has an effect on oil consumption measurement as well, as presented in this paper. The results showed this method can be applied to large gas engines as well after conducting minor changes to the measurement setup. However, other than liquid fuels, the origin and isotopic composition of the natural gas has to be monitored. Ideally, gas from large storage is used for carrying out these measurements.

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Adair, J., D. Olsen, and A. Kirkpatrick. "Exhaust Tuning of Large-Bore, Multicylinder, Two-Stroke, Natural Gas Engines." International Journal of Engine Research 7, no. 2 (April 1, 2006): 131–41. http://dx.doi.org/10.1243/146808705x58297.

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In this paper, computational modelling of the exhaust system of two types of large-bore, multicylinder, two-stroke engine is performed. The airflow performance of a four-cylinder V-bank Cooper GMV-4TF engine and a six-cylinder in-line Clark TLA engine is simulated. The simulation includes the computation of pressure wave propagation in the exhaust manifold. Using a modified method of the steepest ascent numerical technique, tuned exhaust manifolds are designed for each engine with the objective of reduced NO emissions. The NO reduction is accomplished by increasing the trapped cylinder mass and correspondingly reducing the peak combustion temperature. The simulations predict NO reductions in the range 10–30 per cent as a result of exhaust tuning.

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Kim, Gi-Heon, Allan Kirkpatrick, and Charles Mitchell. "Supersonic Virtual Valve Design for Numerical Simulation of a Large-Bore Natural Gas Engine." Journal of Engineering for Gas Turbines and Power 129, no. 4 (February 20, 2007): 1065–71. http://dx.doi.org/10.1115/1.2747251.

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In many applications of supersonic injection devices, three-dimensional computation that can model a complex supersonic jet has become critical. However, in spite of its increasing necessity, it is computationally costly to capture the details of supersonic structures in intricate three-dimensional geometries with moving boundaries. In large-bore stationary natural gas fueled engine research, one of the most promising mixing enhancement technologies currently used for natural gas engines is high-pressure fuel injection. Consequently, this creates considerable interest in three-dimensional computational simulations that can examine the entire injection and mixing process in engines using high-pressure injection and can determine the impact of injector design on engine performance. However, the cost of three-dimensional engine simulations—including a moving piston and the kinetics of combustion and pollutant production—quickly becomes considerable in terms of simulation time requirements. One limiting factor is the modeling of the small length scales of the poppet valve flow. Such length scales can be three orders of magnitude smaller than cylinder length scales. The objective of this paper is to describe the development of a methodology for the design of a simple geometry supersonic virtual valve that can be substituted in three-dimensional numerical models for the complex shrouded poppet valve injection system actually installed in the engine to be simulated. Downstream flow characteristics of the jets from an actual valve and various virtual valves are compared. Relevant mixing parameters, such as local equivalent ratio and turbulence kinetic energy, are evaluated in full-scale moving piston simulations that include the effect of the jet-piston interaction. A comparison of the results has indicated that it is possible to design a simple converging-diverging fuel nozzle that will produce the same jet and, subsequently, the same large-scale and turbulent-scale mixing patterns in the engine cylinder as a real poppet valve.

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Mashayekh, Alireza, Timothy Jacobs, Mark Patterson, and John Etcheverry. "Prediction of air–fuel ratio control of a large-bore natural gas engine using computational fluid dynamic modeling of reed valve dynamics." International Journal of Engine Research 18, no. 9 (January 6, 2017): 900–908. http://dx.doi.org/10.1177/1468087416686224.

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Air–fuel ratio control of large-bore, two-stroke, natural gas engines, typically used in the oil and gas field, is critically important to maintain stable operation and emission compliance. Many two-stroke applications rely on reed valves to control air and gas induction, which can involve complicated gas flow behavior; standard gas dynamic relationships are typically insufficient to characterize such behavior. Computational fluid dynamic simulations offer the needed complexity, but even so the computational fluid dynamic models, as shown in this work, must also capture the dynamic behavior of the valves themselves. The current work reports on a computational fluid dynamics–based model representing this type of large-bore, two-stroke, natural gas engine using commercially available computational fluid dynamic software. The engine under study is an AJAX E-565 with rated power of 30 kW (40 HP), a bore of 216 mm (8½″), and a stroke of 254 mm (10″). The large engine geometry makes a relatively large solution domain, hence requiring an intense, time-consuming numerical investigation. This large-bore engine works at a rated speed of 525 RPM with a compression ratio of 6 to 1. Two approaches to modeling the reed valve are investigated: (1) a pressure difference–based user-defined function and (2) a fluid–structure interaction user-defined function. The pressure difference–based user-defined function captures reed valve behavior in a simple, binary fashion (i.e. valves are either open or closed based on the pressure difference between the intake pipe and the engine’s stuffing box). The fluid–structure interaction user-defined function, however, predicts the motion of the reed valve strips based on fluid and body motions; although a more complex solution, the fluid–structure interaction user-defined function accurately predicts the engine’s gas exchange process. In this article, the results of each method are presented and validated to show that the added complexity is necessary to properly predict (and thus eventually improve) the engine’s air–fuel ratio control.

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Liu, Long, Shihai Liu, Qian Xia, Bo Liu, and Xiuzhen Ma. "Numerical Investigation on Mixing Characteristics and Mechanism of Natural Gas/Air in a Super-Large-Bore Dual-Fuel Marine Engine." Atmosphere 13, no. 9 (September 19, 2022): 1528. http://dx.doi.org/10.3390/atmos13091528.

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Premixed combustion mode dual-fuel (DF) engines are widely used in large-bore marine engines due to their great potential to solve the problem of CO2 emissions. However, detonation is one of the main problems in the development of marine engines based on the premixed combustion mode, which affects the popularization of liquefied natural gas (LNG) engines. Due to the large bore and long stroke, marine dual-fuel engines have unique flow characteristics and a mixture mechanism of natural gas and air. Therefore, the purpose of this study is to present a simulated investigation on the influence of swirl on multiscale mixing and the concentration field, which provides a new supplement for mass transfer theory and engineering applications. It is suggested that the phenomenon of abnormal combustion occurs on account of the distribution of the mixture being uneven in a super-large-bore dual-fuel engine. Further analysis showed that the level of swirl at the late compression stage and the turbulence intensity are the decisive factors affecting the transmission process of natural gas (NG) and distribution of methane (CH4) concentration. Finally, a strategy of improving mixture quality and the distribution of the mixture was proposed.

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11

Olsen, D. B., G. C. Hutcherson, B. D. Willson, and C. E. Mitchell. "Development of the Tracer Gas Method for Large Bore Natural Gas Engines—Part I: Method Validation." Journal of Engineering for Gas Turbines and Power 124, no. 3 (June 19, 2002): 678–85. http://dx.doi.org/10.1115/1.1454116.

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The tracer gas method is investigated as a means to study scavenging in fuel-injected large-bore two-stroke cycle engines. The investigation is performed on a Cooper-Bessemer GMV-4TF natural gas engine, with a 36-cm bore and a 36-cm stroke. Two important parameters are evaluated from the tracer gas measurements, which are scavenging efficiency and trapped A/F ratio. Measurements with the tracer gas method are compared with in-cylinder sampling techniques to evaluate the accuracy of the method. Two different tracers are evaluated, monomethylamine and nitrous oxide. Monomethylamine is investigated because of its common use historically as a tracer gas. Nitrous oxide is a new tracer gas that overcomes many of the difficulties experienced with monomethylamine. The tracer gas method with nitrous oxide is determined to be accurate for evaluating scavenging efficiency and trapped A/F ratio in comparison to the in-cylinder sampling techniques implemented.

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12

Blizzard, D. T., F. S. Schaub, and J. G. Smith. "Development of the Cooper-Bessemer CleanBurn™ Gas-Diesel (Dual-Fuel) Engine." Journal of Engineering for Gas Turbines and Power 114, no. 3 (July 1, 1992): 480–87. http://dx.doi.org/10.1115/1.2906614.

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NOx emission legislation requirements for large-bore internal combustion engines have required engine manufacturers to continue to develop and improve techniques for exhaust emission reduction. This paper describes the development of the Cooper-Bessemer Clean Burn™ gas-diesel (dual-fuel) engine that results in NOx reductions of up to 92 percent as compared with an uncontrolled gas-diesel engine. Historically, the gas-diesel and diesel engine combustion systems have not responded to similar techniques of NOx reduction that have been successful on straight spark-ignited natural gas burning engines. NOx levels of a nominal 1.0 g/BHP-h, equal to the spark-ignited natural gas fueled engine, have been achieved for the gas-diesel and are described. In addition, the higher opacity exhaust plume characteristic of gas-diesel combustion is significantly reduced or eliminated. This achievement is considered to be a major breakthrough, and the concept can be applied to both new and retrofit applications.

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13

Kim, Gi-Heon, Allan Kirkpatrick, and Charles Mitchell. "Computational Modeling of Natural Gas Injection in a Large Bore Engine." Journal of Engineering for Gas Turbines and Power 126, no. 3 (July 1, 2004): 656–64. http://dx.doi.org/10.1115/1.1762906.

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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.

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Foteinos, Michael I., Alexandros Papazoglou, Nikolaos P. Kyrtatos, Anastassios Stamatelos, Olympia Zogou, and Antiopi-Malvina Stamatellou. "A Three-Zone Scavenging Model for Large Two-Stroke Uniflow Marine Engines Using Results from CFD Scavenging Simulations." Energies 12, no. 9 (May 7, 2019): 1719. http://dx.doi.org/10.3390/en12091719.

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The introduction of modern aftertreatment systems in marine diesel engines call for accurate prediction of exhaust gas temperature, since it significantly affects the performance of the aftertreatment system. The scavenging process establishes the initial conditions for combustion, directly affecting exhaust gas temperature, fuel economy, and emissions. In this paper, a semi-empirical zero-dimensional three zone scavenging model applicable to two-stroke uniflow scavenged diesel engines is updated using the results of CFD (computational fluid dynamics) simulations. In this 0-D model, the engine cylinders are divided in three zones (thermodynamic control volumes) namely, the pure air zone, mixing zone, and pure exhaust gas zone. The entrainment of air and exhaust gas in the mixing zone is specified by time varying mixing coefficients. The mixing coefficients were updated using results from CFD simulations based on the geometry of a modern 50 cm bore large two-stroke marine diesel engine. This increased the model’s accuracy by taking into account 2-D fluid dynamics phenomena in the cylinder ports and exhaust valve. Thus, the effect of engine load, inlet port swirl angle and partial covering of inlet ports on engine scavenging were investigated. The three-zone model was then updated and the findings of CFD simulations were reflected accordingly in the updated mixing coefficients of the scavenging model.

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Koehler, Horst W., and Claus Windelev. "Low-Emission Medium-Speed Diesel Engines." Marine Technology and SNAME News 38, no. 04 (October 1, 2001): 261–67. http://dx.doi.org/10.5957/mt1.2001.38.4.261.

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In today's environmentally aware society the large-bore diesel engine is not alone in coming under scrutiny. Although only 0.25 to 0.35% among the total exhaust gases produced by this type of engine are toxious compounds, even such small amounts still need to be reduced further. MAN B&W Diesel, market leaders in the production of large-bore two-and four-stroke diesel engines covering the output bracket between 680 hp and almost 100 000 hp per engine (Fig. 1), have been facing up to this challenge for almost a decade. Taking state-of-the-art MAN B&W four-stroke engines as its example, this paper outlines the causes and effects of the major pollutants, including carbon dioxide, the "greenhouse gas," and describes some of the options available for reducing them [1]. The NOx emission control measures implemented in the current generation of MAN B&W diesel engines ensure that they comply with statutory emission limits. Since the time this paper was compiled (January 2000) much progress has been achieved in reducing pollutant emissions from diesel engines, in particular as regards smoke emissions from cruise vessels slow-steaming in strictly protected tourist areas. As an example the authors' company introduced an IS version (IS = invisible smoke) for their largest medium-speed diesel engines in September 2000, featuring invisible exhaust plumes in transient operation between idling and full load. Fig. 1MAN B&W slow-speed and medium-speed diesel engine program (status: 1999)

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Puzinauskas, Paulius V., Daniel B. Olsen, and Bryan D. Willson. "Cycle-Resolved NO Measurements in a Two-Stroke Large-Bore Natural Gas Engine." Journal of Engineering for Gas Turbines and Power 126, no. 2 (April 1, 2004): 429–41. http://dx.doi.org/10.1115/1.1635401.

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Cycle-resolved NO data were acquired from a Cooper-Bessemer GMV 4TF two-stroke engine to better understand and quantify large bore natural gas engine NOx emission. The cycle resolved NO data were extracted separately from the engine’s cylinder two and four exhaust ports and taken simultaneously with cycle resolved pressure traces, conventional steady-state emission measurements and a variety of additional performance and diagnostic data. The test variables were intake manifold boost pressure, ignition method and ignition timing. Relationships between individual cycle pressure traces and the NO produced by that cycle were investigated. Furthermore, mass-averaged NO values were calculated and integrated in order to compare with average exhaust emissions from a steady-state analyzer and combustion pressure characteristics. The steady measurements revealed that NO and NO2 emissions respond differently to the test variables. The mass averaged cycle-resolved NO values compare well with the steady exhaust emission measurements and exhibit strong correlations with peak pressure and crank angle location of peak pressure.

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Puzinauskas, P. V., D. B. Olsen, and B. D. Willson. "Mass integration of fast-response NO measurements from a two-stroke large-bore natural gas engine." International Journal of Engine Research 4, no. 3 (June 1, 2003): 233–48. http://dx.doi.org/10.1243/146808703322223342.

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A thermodynamic two-stroke-cycle engine simulation with a quasi-steady scavenging model was developed and used to mass-integrate cycle-resolved NO measurements made with a fast-response NO analyser. The engine tested was a Cooper-Bessemer GMV-4TF large-bore natural gas engine and the fast NO measurements were made in cylinders 2 and 4 using a Cambustion fNOx400 two-channel fast-response analyser. The engine simulation was deemed to provide a good representation of the cycle-resolved scavenging mass flow. The mass-integrated NO results were compared to Fourier transform infrared (FTIR) steady measurements taken downstream of the cylinders 2 and 4 exhaust-manifold junction. The correlation between the two techniques was linear to within 2 per cent. A strong correlation was exhibited between mass-integrated cycle-to-cycle NO and measured peak and crank angle location of peak combustion pressure. The correlation with peak pressure was slightly better than the location of peak pressure.

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18

Ruter, Mathew D., Daniel B. Olsen, Mark V. Scotto, and Mark A. Perna. "NOx reduction from a large bore natural gas engine via reformed natural gas prechamber fueling optimization." Fuel 91, no. 1 (January 2012): 298–306. http://dx.doi.org/10.1016/j.fuel.2011.06.072.

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Khoa, Nguyen Xuan, and Ocktaeck Lim. "Comparative Study of the Effective Release Energy, Residual Gas Fraction, and Emission Characteristics with Various Valve Port Diameter-Bore Ratios (VPD/B) of a Four-Stroke Spark Ignition Engine." Energies 13, no. 6 (March 12, 2020): 1330. http://dx.doi.org/10.3390/en13061330.

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In this research, the residual gas, peak firing pressure increase, and effective release energy were completely investigated. To obtain this target, the experimental system is installed with a dynamo system and a simulation model was setup. Through combined experimental and simulation methods, the drawbacks of the hardware optimization method were eliminated. The results of the research show that the valve port diameter-bore ratio (VPD/B) has a significant effect on the residual gas, peak firing pressure increase, and effective release energy of a four-stroke spark ignition engine. In this research, the engine was performed at 3000 rpm and full load condition. Following increased IPD/B ratio of 0.3–0.5. The intake port and exhaust port diameter has a contrary effect on engine volumetric efficiency, the residual gas ratio increase 27.3% with larger intake port and decrease 18.6% with larger exhaust port. The engine will perform optimal thermal efficiency when the trapped residual gas fraction ratio is from 13% to 14%. The maximum effective release energy was 0.45 kJ at 0.4 intake port-bore ratio, and 0.451 kJ at 0.35 exhaust port-bore ratio. The NOx emission increases until achieved a maximum value after that decrease even VPD/B was still increasing. With a VPD/B ratio of 0.35 to 0.4, the engine works without the misfiring.

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Heinz, Christoph, Stefan Kammerstätter, and Thomas Sattelmayer. "Prechamber Ignition Concepts for Stationary Large Bore Gas Engines." MTZ worldwide 73, no. 1 (January 2012): 60–65. http://dx.doi.org/10.1365/s38313-012-0134-5.

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Moszner, Peng, Suutala, Jasnau, Damani, and Palm. "Application of Iron Aluminides in the Combustion Chamber of Large Bore 2-Stroke Marine Engines." Metals 9, no. 8 (July 31, 2019): 847. http://dx.doi.org/10.3390/met9080847.

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Iron aluminides possess a unique combination of properties such as attractive corrosion resistance in hot gas and wet chemical environments, a favorable strength to weight ratio, low costs of alloying elements, and they can be processed by conventional methods. For the current study, a promising iron aluminide (Fe-Al-Mo-Ti-B) was employed, which shows the potential to replace costly heat resistant steels or expensive Ni-based alloys for components in large bore two-stroke marine engines. The prechamber, an integral part of the combustion system of dual fuel two-stroke marine engines, which must withstand harsh conditions, was selected as the component. Prototypes made of the novel iron aluminide were manufactured via investment casting and hot isostatic pressing using powder of the intermetallic alloy. The high temperature oxidation behavior, the wet corrosion resistance in acid media, and the mechanical properties up to 700 °C were evaluated. A prototype of the prechamber was tested on a large bore two-stroke dual fuel test engine and post analysis of the tested component was performed. The results show that the employed iron aluminide alloy could be an economic alternative to the currently used Ni-based alloy.

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Goto, Y. "Development of a liquid natural gas pump and its application to direct injection liquid natural gas engines." International Journal of Engine Research 3, no. 2 (April 1, 2002): 61–68. http://dx.doi.org/10.1243/14680870260127855.

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Direct injection gas engines operated with liquid natural gas (LNG) look promising because the energy density-volume ratio of LNG is three times higher than that of compressed natural gas (CNG) and pressurization of LNG to injection pressures is much easier and expends less energy. Based on these considerations, a prototype of an LNG high-pressure pump, which can achieve a pressure as high as 20 MPa, was developed and tested using nitrogen instead of LNG. It was confirmed that the energy consumption of the LNG pump to pressurize an amount of natural gas is one-eighth the energy consumption of the corresponding CNG pump. A direct injection natural gas engine having a 108 mm bore and a compression ratio of 12 was developed for the evaluation of its performance and emissions. The result of the engine experiment made it clear that the indicated thermal efficiency of the gas engine is approximately 44 per cent over a medium and high load range, which is equivalent to that of the corresponding diesel engine. Since the energy required for pressurizing LNG to 15 MPa is 2–3 per cent of the indicated power of the engine, the LNG engine proposed is considered to have the same level of brake thermal efficiency as the corresponding diesel engine. If a truck vehicle is powered by the direct injection LNG engine and carries an LNG tank with a capacity 1.5 times larger than that of gas oil, the cruising distance of the vehicle could be the same as that of a diesel truck.

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Karmann, Stephan, Stefan Eicheldinger, Maximilian Prager, and Georg Wachtmeister. "Optical and thermodynamic investigations of a methane and hydrogen blend fueled large bore engine." International Journal of Engine Research 23, no. 5 (January 3, 2022): 846–64. http://dx.doi.org/10.1177/14680874211066735.

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The following paper presents thermodynamic and optical investigations of the natural flame and OH radical chemiluminescence of a hydrogen enriched methane combustion compared to natural gas combustion. The engine under investigation is a port-fueled unscavenged prechamber 4.8 L single cylinder large bore engine. The blends under consideration are 2%V, 5%V,10%V, and 40%V of hydrogen expected to be blended within existing natural gas grids in a short and mid-term timeline in order to store green energy from solar and wind. These fuel blends could be used for stabilization of the energy supply by reconverting the renewable fuel CH4/H2 in combined heat and power plants. As expected, admixture of hydrogen extends the ignition limits of the fuel mixture toward lean ranges up to an air-fuel equivalence ratio of almost 2. No negative effect on combustion is observed up to an admixture of 40%V hydrogen. At 40%V hydrogen, abnormal combustion like backfire occurs at an air-fuel equivalence ratio of 1.5. The higher mixtures exhibit increased nitrogen oxide emissions due to higher combustion chamber temperatures, while methane slip and CO emissions are reduced due to more complete combustion. The optical investigation of the natural flame and OH radical chemiluminescence are in good agreement with the thermodynamic results verifying the more intense combustion of the fuel blends by means of the chemiluminescence intensity. Further, lube oil combustion and a continuing luminescence after the thermodynamic end of combustion are observed.

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Olsen, Daniel B., and Bryan D. Willson. "The Effect of Retrofit Technologies on Formaldehyde Emissions from a Large Bore Natural Gas Engine." Energy and Power Engineering 03, no. 04 (2011): 574–79. http://dx.doi.org/10.4236/epe.2011.34071.

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Wang, Tianbo, Siqin Chang, Liang Liu, Jianhui Zhu, and Yaxuan Xu. "Individual cylinder air–fuel ratio estimation and control for a large-bore gas fuel engine." International Journal of Distributed Sensor Networks 15, no. 2 (February 2019): 155014771983362. http://dx.doi.org/10.1177/1550147719833629.

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Richardson, D. E., and S. A. Krause. "Predicted Effects of Cylinder Kit Wear on Blowby and Oil Consumption for Two Diesel Engines." Journal of Engineering for Gas Turbines and Power 122, no. 4 (November 22, 1999): 520–25. http://dx.doi.org/10.1115/1.1286674.

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Durability is very important for current diesel engines. Diesel engine manufacturers are trying to make the engines live as long as possible before overhaul. The time to overhaul for an engine is usually dictated by high oil consumption or blowby. Therefore, it is necessary to understand how wear affects the cylinder kit dynamics, oil consumption, and blowby in an engine. This paper explores the effect of power cylinder component (rings and cylinder bore) wear by using a cylinder kit dynamics model. The model predicts how wear will affect ring motion, inter-ring gas pressure, blowby, etc. The parameters studied were: liner wear, ring face wear, and ring side wear. Two different engines were modeled. The characteristics of these two engines are very different. As a result, the effects of wear are different and the corresponding durability will be different. This illustrates the need to model each individual type of engine separately. The modeling shows that top ring face wear is very significant for maintaining good oil and blowby control. Liner wear is important, but does not have as large an effect as ring wear. The effects of side wear are significant for these two cases. [S0742-4795(00)00203-9]

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Liu, Long, Yue Wu, and Yang Wang. "Numerical investigation on knock characteristics and mechanism of large-bore natural gas dual-fuel marine engine." Fuel 310 (February 2022): 122298. http://dx.doi.org/10.1016/j.fuel.2021.122298.

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Vítek, Oldřich, Jan Macek, Jiří Klíma, and Martin Vacek. "Optimization of 2‑Stage Turbocharged Gas SI Engine Under Steady State Operation." Journal of Middle European Construction and Design of Cars 15, no. 2 (December 20, 2017): 9–36. http://dx.doi.org/10.1515/mecdc-2017-0006.

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Abstract The proposed paper deals with an optimization of a highly-turbocharged large-bore gas SI engine. Only steady state operation (constant engine speed and load) is considered. The paper is mainly focused on theoretical potential of 2-stage turbocharging concept in terms of performance and limitation. The results are obtained by means of simulation using complex 0-D/ 1-D engine model including the control algorithm. Different mixture composition concepts are considered to satisfy different levels of NOx limit - fresh air mixed with external cooled EGR is supposed to be the right approach while optimal EGR level is to be found. Considering EGR circuit, 5 different layouts are tested to select the best design. As the engine control is relatively complex (2-sage turbocharger group, external EGR, compressor blow-by, controlled air excess), 5 different control means of boost pressure were considered. Each variant based on above mentioned options is optimized in terms of compressor/turbine size (swallowing capacity) to obtain the best possible BSFC. The optimal variants are compared and general conclusions are drawn.

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Ye, Ying, Zongyu Yue, Hu Wang, Haifeng Liu, Chaohui Wu, and Mingfa Yao. "A Mapping Approach for Efficient CFD Simulation of Low-Speed Large-Bore Marine Engine with Pre-Chamber and Dual-Fuel Operation." Energies 14, no. 19 (September 26, 2021): 6126. http://dx.doi.org/10.3390/en14196126.

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A natural-gas-diesel dual-fuel marine engine with a pre-chamber is a promising solution for ocean transportation to meet the International Maritime Organization (IMO) emission regulations. This engine system employs a pre-chamber with direct injection of diesel to ignite premixed natural gas due to its higher ignition energy, which can enable lower lean limit and higher thermal efficiency. The dual-fuel pre-chamber marine engine presents complex multi-regime combustion characteristics in- and outside the pre-chamber, thus posing challenges in its numerical simulation in a cost-effective manner. Therefore, this paper presents a three-dimensional modeling study for the multi-regime combustion in a large-bore two-stroke marine dual-fuel engine, proposing a novel mapping approach, which couples the well-stirred reactor (WSR) model with the G-equation model to achieve high computational accuracy and efficiency simultaneously. In-depth analysis is performed using representative exothermic reaction (RXR) analysis and premixed turbulent combustion fundamentals to better understand the combustion process and to provide guidance in the selection of mapping timing. The results show that the use of mapping to switch from the WSR to the G-equation model can effectively reduce the runtime significantly by 71.5%, meanwhile maintaining similar accuracies in predictions of in-cylinder pressure traces, HRR and NOx emissions, compared to using WSR all along. Additionally, the choice of mapping timing based on several parameters is preliminarily discussed.

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Ghafouri, Jafar, Sina Shafee, and Amin Maghbouli. "Investigation on effect of equivalence ratio and engine speed on homogeneous charge compression ignition combustion using chemistry based CFD code." Thermal Science 18, no. 1 (2014): 89–96. http://dx.doi.org/10.2298/tsci130204128g.

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Combustion in a large-bore natural gas fuelled diesel engine operating under Homogeneous Charge Compression Ignition mode at various operating conditions is investigated in the present paper. Computational Fluid Dynamics model with integrated chemistry solver is utilized and methane is used as surrogate of natural gas fuel. Detailed chemical kinetics mechanism is used for simulation of methane combustion. The model results are validated using experimental data by Aceves, et al. (2000), conducted on the single cylinder Volvo TD100 engine operating at Homogeneous Charge Compression Ignition conditions. After verification of model predictions using in-cylinder pressure histories, the effect of varying equivalence ratio and engine speed on combustion parameters of the engine is studied. Results indicate that increasing engine speed provides shorter time for combustion at the same equivalence ratio such that at higher engine speeds, with constant equivalence ratio, combustion misfires. At lower engine speed, ignition delay is shortened and combustion advances. It was observed that increasing the equivalence ratio retards the combustion due to compressive heating effect in one of the test cases at lower initial pressure. Peak pressure magnitude is increased at higher equivalence ratios due to higher energy input.

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31

Khoa, Nguyen Xuan, and Ocktaeck Lim. "The Internal Residual Gas and Effective Release Energy of a Spark-Ignition Engine with Various Inlet Port–Bore Ratios and Full Load Condition." Energies 14, no. 13 (June 23, 2021): 3773. http://dx.doi.org/10.3390/en14133773.

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This paper presents the effect of inlet port diameter–bore ratios (IPD/B) on the effective release energy and internal exhaust residual gas of a spark-ignition engine. To investigate the exhaust residual gas in the combustion chamber, a simulation model is setup based on AVL-boost software, and to validate the simulation model an experimental model is also setup. The results of the research show that: the IPD/B ratios have a large effect on the residual gas and effective release energy. When the IPD/B ratio increases from 0.3–0.5, the residual gas increases from 0.11% to 0.14%, and the effective release energy increases from 0.33 KJ to a maximum value of 0.45 KJ, and after that decreases. The engine shows the maximum effective release energy at IPD/B ratio is 0.4. The emission of HC and CO is decreased, but the NOx is increased until a maximum value after that decreased.

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Guo, Hao, Song Zhou, Jiaxuan Zou, and Majed Shreka. "A Numerical Study on the Pilot Injection Conditions of a Marine 2-Stroke Lean-Burn Dual Fuel Engine." Processes 8, no. 11 (November 2, 2020): 1396. http://dx.doi.org/10.3390/pr8111396.

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The global demand for clean fuels is increasing in order to meet the requirements of the International Maritime Organization (IMO) of 0.5% global Sulphur cap and Tier III emission limits. Natural gas has begun to be popularized on liquefied natural gas (LNG) ships because of its low cost and environment friendly. In large-bore marine engines, ignition with pilot fuel in the prechamber is a good way to reduce combustion variability and extend the lean-burn limit. However, the occurrence of knock limits the increase in power. Therefore, this paper investigates the effect of pilot fuel injection conditions on performance and knocking of a marine 2-stroke low-pressure dual-fuel (LP-DF) engine. The engine simulations were performed under different pilot fuel parameters. The results showed that the average in-cylinder temperature, the average in-cylinder pressure, and the NOx emissions gradually decreased with the delay of the pilot injection timing. Furthermore, the combustion situation gradually deteriorated as the pilot injection duration increased. A shorter pilot injection duration was beneficial to reduce NOx pollutant emissions. Moreover, the number of pilot injector orifices affected the ignition of pilot fuel and the flame propagation speed inside the combustion chamber.

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Li, Y., A. Kirkpatrick, C. Mitchell, and B. Willson. "Characteristic and Computational Fluid Dynamics Modeling of High-Pressure Gas Jet Injection." Journal of Engineering for Gas Turbines and Power 126, no. 1 (January 1, 2004): 192–97. http://dx.doi.org/10.1115/1.1635398.

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The topic of this paper is the 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 supply pressure/cylinder stagnation pressure ratio, with ratios ranging from 3 to 80, on the velocity and pressure profiles in the near field region. Computational fluid dynamics modeling was compared with results obtained from a two-dimensional analytical method of characteristics solution and experimental results. The comparison process evaluated factors such as pressure and Mach number profiles, jet boundary shape, and shock location.

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Szpica, Dariusz, Bogusław Toczko, Andrzej Borawski, and Grzegorz Mieczkowski. "Experimental Evaluation of the Influence of the Diameter of the Outlet Nozzle Bore of a Gas Injector on Its Flow Characteristic." Applied Sciences 13, no. 3 (January 29, 2023): 1700. http://dx.doi.org/10.3390/app13031700.

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Despite the growing share of electrically powered vehicles, internal combustion engines are still one of the primary sources of propulsion in transportation. One way to decarbonize engines is to use alternative fuels, where liquefied petroleum gas (LPG) accounts for a large share. Popular car gas systems are LPG indirect vapor phase injection systems, in which the low-pressure gas-phase injector is the actuator. The purpose of the research and analysis presented in this paper is to determine the flow characteristics of three injectors that are structurally different depending on the diameter of the outlet nozzle bore. The tests are conducted, which is new, with pulsed operation of the injector, which, as it turned out, helps explain the discrepancies found. The obtained characteristics are fitted with a polynomial of the second degree, obtaining high-quality indices. In the group of three tested injectors, the average values of volumetric flow rate decreases relative to the maximum by 19.6 and 35.8%. Differences in opening times of 29.3 and 36.6%, respectively, are cited as one of the main reasons for this. Closing times are similar to each other. In addition, the injector with the highest volumetric flow rate and the shortest opening time obtains 1.8 and 9.94% lower average cycle pressures measured at the outlet of the injector nozzle. The differences in opening times and average cycle pressures are considered as possible reasons for the differences in flow characteristics. The obtained characteristics are applicable to engine conversions and calculations.

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Ji, Shaobo, Xin Lan, Yong Cheng, Xiuliang Zhao, Xinhai Li, and Fengjuan Wang. "Cyclic variation of large-bore multi point injection engine fuelled by natural gas with different types of injection systems." Applied Thermal Engineering 102 (June 2016): 1241–49. http://dx.doi.org/10.1016/j.applthermaleng.2016.03.082.

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36

Karmann, Stephan, Stefan Eicheldinger, Maximilian Prager, Malte Jaensch, and Georg Wachtmeister. "Optical and Thermodynamic Investigations of a Methane- and Hydrogen-Blend-Fueled Large-Bore Engine Using a Fisheye Optical System." Energies 16, no. 4 (February 5, 2023): 1590. http://dx.doi.org/10.3390/en16041590.

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The following paper presents thermodynamic and optical investigations of hydrogen-enriched methane combustion, showing the potential of a hydrogen admixture as a means to decarbonize stationary power generation. The optical investigations are carried out through a fisheye optical system directly mounted into the combustion chamber, replacing one exhaust valve. All of the tests were carried out with constant fuel energy producing 16 bar indicated mean effective pressure. The engine under investigation is a port-fueled 4.8 l single-cylinder large-bore research engine. The test series compared the differences between a conventional spark plug and an unscavenged pre-chamber spark plug as an ignition system. The fuel blends under investigation are 5 and 10%V hydrogen mixed with methane and pure natural gas acting as a reference fuel. The thermodynamic results show a beneficial influence of the hydrogen admixture on both ignition systems and for all variations concerning the lean running limit, combustion stability and indicated efficiency, with the most significant influence being visible for the tests using conventional spark plugs. With the unscavenged pre-chamber spark plug and the combustion of the 10%V hydrogen admixture, an increase in the indicated efficiency of 0.8% compared to NG is achievable. The natural chemiluminescence intensity traces were observed to be predominantly influenced by the air–fuel equivalence ratio. This results in a 20% higher intensity for the unscavenged pre-chamber spark plug for the combustion of 10%V hydrogen compared to the conventional spark plug. This is also visible in the evaluations of the flame color derived from the dewarped combustion image series. The investigation of the torch flames also shows a difference in the air–fuel equivalence ratio but not between the different fuels. The results encourage the development of hydrogen-based fuels and the potential to store surplus sustainable energy in the form of hydrogen in existing gas grids.

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Imperato, Matteo, Ossi Kaario, Teemu Sarjovaara, and Martti Larmi. "Influence of the in-cylinder gas density and fuel injection pressure on the combustion characteristics in a large-bore diesel engine." International Journal of Engine Research 17, no. 5 (June 2, 2015): 525–33. http://dx.doi.org/10.1177/1468087415589043.

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Renz, Alexander, Dominik Kürten, and Oliver Lehmann. "Wear of hardfaced valve spindles in highly loaded stationary lean-burn large bore gas engines." Wear 376-377 (April 2017): 1652–61. http://dx.doi.org/10.1016/j.wear.2016.12.045.

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Wellander, Rikard, Joakim Rosell, Mattias Richter, Marcus Alden, Oivind Andersson, Bengt Johansson, Jeudi Duong, and Jari Hyvonen. "Study of the Early Flame Development in a Spark-Ignited Lean Burn Four-Stroke Large Bore Gas Engine by Fuel Tracer PLIF." SAE International Journal of Engines 7, no. 2 (April 1, 2014): 928–36. http://dx.doi.org/10.4271/2014-01-1330.

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Zhang, Qiang, Kai Xian, and Menghan Li. "Investigation of Performance and Emission Characteristics on a Large-Bore Spark-Ignition Natural Gas Engine with Scavenged Prechamber and Miller Cycle Attribute." Journal of Energy Engineering 143, no. 5 (October 2017): 04017026. http://dx.doi.org/10.1061/(asce)ey.1943-7897.0000452.

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41

Wahl, Jonas, and Josef Kallo. "Quantitative valuation of hydrogen blending in European gas grids and its impact on the combustion process of large-bore gas engines." International Journal of Hydrogen Energy 45, no. 56 (November 2020): 32534–46. http://dx.doi.org/10.1016/j.ijhydene.2020.08.184.

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Neidel, A., T. Gädicke, and S. Riesenbeck. "Metallurgical Failure Investigation of Fractured Dog Bone Seal Retainer Ring Fillet Welds in the Turbine Exhaust Casing of a Heavy-duty Gas Turbine Engine." Practical Metallography 58, no. 11 (November 1, 2021): 715–24. http://dx.doi.org/10.1515/pm-2021-0063.

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Abstract Short fillet welds used to fasten a large retainer ring to so-called dog bone seals failed in the turbine exhaust casing of a non-OEM heavy-duty gas turbine engine used for power generation. The subject fillet welds fractured due to high cycle fatigue loading. Neither weld imperfections nor any other material defects were found that could have contributed to the failure. It was concluded that an unfavorable design, specifying very short fillet welds for fastening the dog bone seal segments to the retainer ring, was the root cause of failure. In a purely static loading situation, this design would probably not have failed. However, in a dynamic loading scenario as is the case in any gas turbine engine exhaust, such a design is simply not sturdy enough.

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Emberson, David, Judit Sandquist, Terese Løvås, Alessandro Schönborn, and Inge Saanum. "Varying Ignition Quality of a Fuel for a HCCI Engine Using a Photochemically-Controlled Additive: The Development of a ‘Smart’ Fuel." Energies 14, no. 5 (March 8, 2021): 1470. http://dx.doi.org/10.3390/en14051470.

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This study examines the possibility to provide control over ignition timing in a homogeneous charge compression ignition engine (HCCI) using a fuel additive whose molecular structure can be adapted upon exposure to UV light. The UV adapted molecule has a greater influence on retarding ignition than the original molecule, hence the ignition time can be modulated upon expose to UV light. The new fuel is referred to as a ‘smart fuel’. The fuel additive is in the form of 1,3-cyclohexadiene (CHD), upon UV exposure it undergoes electro-cyclic ring opening to form 1,3,5-hexatriene (HT). Various solutions of iso-octane, n-heptane and CHD have been irradiated by UV light for different amounts of time. CHD to HT conversion was examined using gas chromatography coupled with mass spectrometry. A primary reference fuel (PRF) mixture of 90% iso-octane and 10% n-heptane was used as a baseline in an optically accessible combustion chamber in a large bore, single cylinder compression ignition engine. The engine was operated in HCCI mode, using early injection to provide homogeneous mixture and utilized heated and compressed air intake. Following this a PRF with 5% CHD was used in the engine. A PRF with 5% CHD was then irradiated with UV light for 240 min, resulting in a PRF mixture containing 1.72% HT, this was then used in the engine. The HT containing PRF had a much later start of combustion compared with the CHD containing PRF, which in turn had a later start of combustion compared with the PRF baseline. This study has successfully validated the concept of using a photo-chemical ‘smart’ fuel to significantly change the ignition quality of a fuel in HCCI mode combustion and demonstrated the concept of on-board ‘smart fuel’ applications for ICE.

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Duan, Xiongbo, Banglin Deng, Yiqun Liu, Shunzhang Zou, Jingping Liu, and Renhua Feng. "An experimental study the impact of the hydrogen enrichment on cycle-to-cycle variations of the large bore and lean burn natural gas spark-ignition engine." Fuel 282 (December 2020): 118868. http://dx.doi.org/10.1016/j.fuel.2020.118868.

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Ogawa, Hideyuki, Akihiro Morita, Katsushi Futagami, and Gen Shibata. "Ignition delays in diesel combustion and intake gas conditions." International Journal of Engine Research 19, no. 8 (September 25, 2017): 805–12. http://dx.doi.org/10.1177/1468087417731410.

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Ignition delays in diesel combustion under several intake gas conditions, including different oxygen concentrations changed with exhaust gas recirculation quantities and different intake gas temperatures, were measured for four cetane numbers and three compression ratios in a single-cylinder, naturally aspirated, direct injection diesel engine (bore: 110 mm, stroke: 106 mm, and stroke volume: 1007 cm3). The engine has a common rail fuel injection system which can be set to optional injection timings and has an injector with a needle lift sensor to accurately estimate the injection timing. The intake oxygen concentrations were set by the quantity of exhaust gas recirculation gas, and the intake gas temperatures were changed with a water-cooled exhaust gas recirculation cooler and an electric heater in the intake pipe. Three compression ratios, 16.7, 18.0, and 21.3, were established with three pistons of different cavity volumes. Four fuels with different cetane numbers, 32 (CN32), 45 (CN45), 57 (CN57), and 78 (CN78), consisting of normal and isoparaffins, were examined for the three compression ratios, and the influence of exhaust gas recirculation and intake gas temperature is discussed for 12 combinations of compression ratios and cetane numbers. The results showed that the ignition delay increases linearly with the 1.67 power of the decrease in the intake oxygen concentration changed with cooled exhaust gas recirculation at the same cetane number and the same compression ratio. The ignition delay increases linearly with lowering intake gas temperatures, and the degree of increase in the ignition delay is more significant with lower cetane number fuels and lower compression ratios. Under practical conditions with the intake oxygen concentration between 21% and 11% and the intake gas temperature between 40°C and 100°C, the changes in ignition delays with the intake oxygen concentration are more significant than the changes with intake gas temperature. The ignition delay increases linearly with lowering compression ratios, and the degree of increase in the ignition delay with reductions in the compression ratio is larger in the cases with lower intake oxygen concentrations and lower cetane number fuels. The ignition delays at the higher compression ratios are significantly shorter than with the lower compression ratios in the case of the same in-cylinder gas temperature at top dead center due to higher in-cylinder gas pressures. The degree of increase in the ignition delay with lower cetane numbers is more significant at lower intake oxygen concentrations and lower compression ratios, and the ignition delay decreases linearly with the 0.25 power of the increase in cetane numbers.

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Göös, Jussi, Anton Leppänen, Antti Mäntylä, and Tero Frondelius. "Large Bore Connecting Rod Simulations." Rakenteiden Mekaniikka 50, no. 3 (August 21, 2017): 275–78. http://dx.doi.org/10.23998/rm.64658.

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On combustion engine a connecting rod converts the reciprocating motion of a piston to the rotating motion of a crankshaft. Simulation of a large bore connection rod has been performed in Abaqus Standard, using boundary conditions from AVL EXCITE Power Unit. By using the latest simulation technologies and the well known boundary conditions, simulated stresses correspond very well with the measured ones from a running engine.

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Mäntylä, Antti, Jussi Göös, Anton Leppänen, and Tero Frondelius. "Large bore engine connecting rod fretting analysis." Rakenteiden Mekaniikka 50, no. 3 (August 21, 2017): 239–43. http://dx.doi.org/10.23998/rm.64914.

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A detailed contact analysis of a large connecting rod was performed to evaluatethe fretting risk in the big end. Simulation was carried out in Abaqus considering all relevantboundary conditions, such as assembly loads, housing machining and dynamics from a exiblemultibody simulation with elastohydrodynamic bearings. Being one of the most importantvariables, the local coeffcient of friction (COF) and its evolution is calculated during the solutionby using a subroutine in Abaqus. The model is validated by strain gauge measurements in arunning engine. The resulted friction coefficient distribution matches well with the ndings froma laboratory engine. The described methodology increases the accuracy of the fretting damageprediction by using a more realistic friction coefficient denition.

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Widener, Christian A., Marius Ellingsen, and Michael Carter. "Understanding Cold Spray for Enhanced Manufacturing Sustainability." Materials Science Forum 941 (December 2018): 1867–73. http://dx.doi.org/10.4028/www.scientific.net/msf.941.1867.

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High pressure cold spray has been showing increasing promise and application for structural repairs and coating applications where wrought like strengths are required. For example, numerous applications have been developed for repairing high cost and long lead time parts for the aerospace and defense market, such as aircraft skin panels, titanium hydraulic lines, aluminum valve actuator internal bores, hardened and chromed steel shafts, gas turbine engine parts, magnesium castings, and many more. These processes also have direct application in commercial markets like transportation and heavy industry. In particular, parts with lead times in excess of 12 months have been successfully repaired and re-introduced into service. This saves not only the direct cost of the part, but also returns the system to service much sooner. Additional benefits of field application with a hand-held nozzle assembly are also possible, particularly for power plants, refineries, and other large industrial plant operations. Cold spray consequently has a tremendous opportunity to enhance manufacturing sustainability by repairing parts that previously could only be replaced and recycled. It is environmentally friendly, as there are no toxic fumes or other harmful emissions from cold spray. Furthermore, because parts are being repaired and refurbished rather than replaced, there is tremendous cost, energy, and overall environmental benefit, making cold spray a “green” technology and an excellent technology for enhancing the long-term sustainability of high value assets.

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Thompson, F., I. Terziev, and I. Taggart. "LARGE-BORE GAS WELL DESIGN—APPLICATION TO OFFSHORE GAS FIELD DEVELOPMENT." APPEA Journal 46, no. 1 (2006): 79. http://dx.doi.org/10.1071/aj05005.

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Offshore gas development projects including the North West Shelf of Australia continue to develop new technologies in order to reduce development costs. Given that the number of development wells directly relates to capital expenditure, past attempts have focussed on obtaining higher gas rates out of conventional well designs by carefully managing erosional limits, which, in turn, tend to restrict the use of higher offtake rates.A strategy based on safely flowing gas wells at higher rates results in fewer wells and delays the phasing-in of additional wells, both of which result in economic enhancement. In recent times the industry has increasingly moved to large-bore gas well technology as a means of realising this strategy. Large-bore gas wells are defined as wells equipped with production tubing and flow control devices larger than 7” or 177 mm. Originally developed for land-based operations, this technology is increasingly moving offshore into totally subsea systems. One factor limiting the speed of adoption of this technology is the trade-off that exists between the increased offtake rates offered by large-bore systems and the risks posed by wear due to erosion in and around the wellhead area caused by any solids entrained in the gas stream.The problem becomes more acute when different-sized well designs employ the same wellhead configurations, because the upper wellhead area is usually the critical and limiting wear component.This paper summarises the recent developments in large-bore offshore applications and presents a consistent methodology showing how different gas well designs can be compared using hydraulic and erosional considerations. Additional trade-offs posed by reliable solids monitoring and the adoption of untested wellhead and intervention designs are discussed. In many cases, hybrid designs based on large diameter tubulars but with conventional wellheads may offer a useful balance between higher well rates and adoption of proven technology. The results shown here are directly applicable to alternative well designs presently under consideration for a number of offshore reservoir developments.

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Chuahy, Flavio DF, Jamen Olk, Dan DelVescovo, and Sage L. Kokjohn. "An engine size–scaling method for kinetically controlled combustion strategies." International Journal of Engine Research 21, no. 6 (July 15, 2018): 927–47. http://dx.doi.org/10.1177/1468087418786130.

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A substantial amount of research has recently focused on kinetically controlled combustion strategies such as reactivity-controlled compression ignition combustion. These strategies are promising methods to achieve high efficiency with near-zero NOx and soot emissions; however, despite promising results, very few attempts have been made to develop size-scaling relationships that would allow these results to be generalized to any engine design. Engine design is a long and arduous process that requires a substantial amount of experimental work. Consequently, it is of interest to develop scaling laws that allow results from one engine to be extrapolated to new designs. Several scaling laws have been proposed for diffusion combustion (i.e. mixing limited) that scale parameters such as liquid length and lift-off length. Such parameters have been deemed unimportant for highly premixed low-temperature combustion strategies; thus, a new methodology is needed. The present effort uses a combination of detailed computational fluid dynamics simulations and engine experiments in two engines with different bore sizes to develop a new engine size–scaling methodology for low-temperature kinetically controlled combustion strategies. The effects of pressure, temperature, and turbulence timescales are explored in order to replicate the large-bore engine performance in a small-bore engine. A size-scaling relationship based on the ignition timescale is proposed and used to generalize the results to an arbitrary bore size and fuel combination.

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Journal articles on the topic 'Large bore gas engine'

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