Combustion of lean fuel mixtures with subcritical streamer microwave discharge

Shock-tube experiments and chemical kinetics modeling were performed to further understand the ignition and oxidation kinetics of lean methane-based fuel blends at gas turbine pressures. Ignition delay times were obtained behind reflected shock waves for fuel mixtures consisting of CH4, CH4/H2, CH4/C2H6, and CH4/C3H8 in ratios ranging from 90/10 to 60/40%. Lean fuel/air equivalence ratios (φ = 0.5) were utilized, and the test pressures ranged from 0.54 to 25.3 atm. A methane-oxidation kinetics mechanism based on GRI-Mech 3.0 was assembled to reproduce the methane/air mixtures. Additional reactions involving CH3O and CH3O2 chemistry and modifications to a few of the pressure-dependent reaction rate coefficients were needed to achieve good agreement between data and model.

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MEMS Across the Valley of Death

Mechanical Engineering ◽

10.1115/1.2006-apr-1 ◽

2006 ◽

Vol 128 (04) ◽

pp. 26-30 ◽

Cited By ~ 2

Author(s):

Alan S. Brown

Keyword(s):

Microelectromechanical Systems ◽

Real Problem ◽

Venture Capitalists ◽

Jet Engines ◽

Angular Rotation ◽

Chip Size ◽

Lean Fuel ◽

Fuel Mixtures ◽

The Right ◽

Valley Of Death

This paper elaborates increasing use of microelectromechanical systems (MEMS) in aerospace industry. MEMS are chip-size devices usually carved from semiconductor wafers. Jet engines running lean fuel mixtures are prone to instability. High-temperature MEMS sensors could improve performance and fuel mileage while reducing emissions. The paper also discusses different MEMS structures, as MEMS structures vary greatly. The oscillating proofmass structures sense angular rotation around an axis in the gyro on the right. The industry has also begun to build a more innovation-ready infrastructure. The MEMS and Nanotechnology Exchange provides another way to ease the tortuous path to commercialization. It promises more prototypes, and more technologies will flow from MEMS inventors in the future. However, experts believe that the real problem is that until more MEMS companies begin making money in aerospace, venture capitalists hesitate to fund their companies.

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Performance of Auto-Cyclic Reactor in Catalytic Combustion of Lean Fuel Mixtures

Industrial & Engineering Chemistry Research ◽

10.1021/ie050819r ◽

2005 ◽

Vol 44 (25) ◽

pp. 9676-9682 ◽

Cited By ~ 5

Author(s):

Danilo Klvana ◽

Jamal Chaouki ◽

Christophe Guy ◽

Jitka Kirchnerova ◽

Massimiliano Zanoletti

Keyword(s):

Catalytic Combustion ◽

Lean Fuel ◽

Fuel Mixtures

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Detection method of combustion oscillation characteristics under strong noise background

Mechanics & Industry ◽

10.1051/meca/2020085 ◽

2020 ◽

Vol 21 (6) ◽

pp. 612

Author(s):

Yunkun Wei ◽

Tianhong Zhang ◽

Zhonglin Lin ◽

Qi Xie ◽

Yan Zhang

Keyword(s):

Radiation Thermometry ◽

Hydroxyl Group ◽

Interference Signal ◽

Engine Vibration ◽

Combustion Technology ◽

Lean Fuel ◽

Combustion Oscillation ◽

Aero Engines ◽

Temperature Measurement System ◽

Multispectral Radiation Thermometry

After the lean fuel premixed combustion technology is applied to aero engines, severe combustion oscillations will be cased and led to hidden safety hazards such as engine vibration, further energy waste and other problems. Therefore, it is increasingly important to actively control combustion oscillations. In this paper, a multispectral radiation thermometry (MRT) is used to analyze the hydroxyl group, which is a measurable research object in the combustion chamber of an aero engine, and to fit the functional relationship between the radiation intensity ratio and the temperature in different bands. The theoretical value of the error is <2%. At the same time, in order to solve the problem of weak detection signal and excessive interference signal, an improved frequency domain filtering method based on fast Fourier transform is designed. Besides, the FPGA platform is used to ensure the real-time performance of the temperature measurement system, and simulations and experiments are performed. An oscillating signal with an oscillation frequency of 315 Hz is obtained on the established test platform, and the error is only 1.42%.

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Design of an External Combustion Engine and its Application in a Free Piston Compressor

Vanderbilt Undergraduate Research Journal ◽

10.15695/vurj.v3i0.2769 ◽

2007 ◽

Vol 3 ◽

Author(s):

Jonathan Hogan Webb

Keyword(s):

Combustion Engine ◽

Piston Compressor ◽

Dead Volume ◽

Transfer Energy ◽

Free Piston ◽

Combustion Gases ◽

Intermediate Chamber ◽

Fuel Mixtures ◽

External Combustion ◽

External Combustion Engine

The design of a free piston compressor and an analysis on integrating an external combustion engine into the compressor design are presented in this article. A free piston compressor is a device which converts chemical energy to work on a volume of air through the kinetic energy of an inertia driven piston, which is not rigidly attached to a ground. An external combustion engine serves as in intermediate chamber which transfers combustion gases to a device to perform some work. The following discusses the design and experiments on an external combustion engine, with a focus on eliminating an injection holding force on a free piston compressor’s elastomeric membranes. The efficiency of the external combustion engine to transfer energy without significant losses due to heat, dead volume, air/fuel mixtures, and actuated valve speed are also presented.

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Development of a Miniature Microwave Discharge Neutralizer for Miniature Ion Engines

JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES ◽

10.2322/jjsass.62.123 ◽

2014 ◽

Vol 62 (4) ◽

pp. 123-128 ◽

Cited By ~ 1

Author(s):

Naoji YAMAMOTO ◽

Yoshiaki HIRAOKA ◽

Hideki NAKASHIMA

Keyword(s):

Microwave Discharge

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Experimental Sensitivity Analysis of Operational Points of the Microwave-discharge Miniature Ion Thruster

JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES ◽

10.2322/jjsass.67.74 ◽

2019 ◽

Vol 67 (3) ◽

pp. 74-80

Author(s):

Yuichi Nakagawa ◽

Mirai Iida ◽

Taishi Yoshitake ◽

Hiroyuki Koizumi ◽

Kimiya Komurasaki

Keyword(s):

Sensitivity Analysis ◽

Microwave Discharge ◽

Ion Thruster

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Pollutant emission from a heat station supplied with agriculture biomass and wood pellet mixture

Chemical and Process Engineering ◽

10.2478/v10176-012-0020-3 ◽

2012 ◽

Vol 33 (2) ◽

pp. 231-242 ◽

Cited By ~ 4

Author(s):

Marek Juszczak ◽

Katarzyna Lossy

Keyword(s):

Carbon Monoxide ◽

Pollutant Emission ◽

Heat Output ◽

Wood Pellets ◽

Wood Pellet ◽

Carbon Monoxide Concentration ◽

Heat Efficiency ◽

Air Stream ◽

Fuel Mixtures ◽

Lower Carbon

Pollutant emission from a heat station supplied with agriculture biomass and wood pellet mixtureTests for combustion of hay and sunflower husk pellets mixed with wood pellets were performed in a horizontal-feed as well as under-feed (retort) wood pellet furnace installed in boilers with a nominal heat output of 15 and 20 kW, located in a heat station. During the combustion a slagging phenomenon was observed in the furnaces. In order to lower the temperature in the furnace, fuel feeding rate was reduced with unaltered air stream rate. The higher the proportion of wood pellets in the mixture the lower carbon monoxide concentration. The following results of carbon monoxide concentration (in mg/m3presented for 10% O2content in flue gas) for different furnaces and fuel mixtures (proportion in wt%) were obtained: horizontal-feed furnace supplied with hay/wood: 0/100 - 326; 30/70 - 157; 50/50 - 301; 100/0 - 3300; horizontal-feed furnace supplied with sunflower husk/wood: 50/50 - 1062; 67/33 - 1721; 100/0 - 3775; under-feed (retort) furnace supplied with hay/wood: 0/100 - 90; 15/85 - 157; 30/70 - 135; 50/50 - 5179; under-feed furnace supplied with sunflower husk/wood: 67/33 - 2498; 100/0 - 3128. Boiler heat output and heat efficiency was low: 7 to 13 kW and about 55%, respectively, for the boiler with horizontal-feed furnace and 9 to 14 kW and 64%, respectively, for the boiler with under-feed furnace.

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