Experimental and computational investigation of the influence of stoichiometric mixture fraction on structure and extinction of laminar, nonpremixed dimethyl ether flames

2018 ◽  
Vol 23 (2) ◽  
pp. 376-386 ◽  
Author(s):  
Gerald Mairinger ◽  
Rohit Sanjay Khare ◽  
Krithika Narayanaswamy ◽  
Martin Hunyadi-Gall ◽  
Vasudevan Raghavan ◽  
...  
Keyword(s):  
Dimethyl Ether ◽  
Mixture Fraction ◽  
Computational Investigation ◽  
Stoichiometric Mixture

scholarly journals Effect of stoichiometric mixture fraction on soot fraction and emission spectra with application to oxy-combustion

2019 ◽  
Vol 37 (4) ◽  
pp. 4571-4578 ◽  
Author(s):  
Chun Lou ◽  
Xiaobing Chen ◽  
Weijie Yan ◽  
Yanfei Tian ◽  
Benjamin M. Kumfer
Keyword(s):  
Mixture Fraction ◽  
Emission Spectra ◽  
Stoichiometric Mixture

Effects of H2-Enrichment on the Propagation Characteristics of CH4-Air Flames

2006 ◽  
Author(s):  
Alejandro M. Briones ◽  
Suresh K. Aggarwal ◽  
Vishwanath R. Katta
Keyword(s):  
Flame Propagation ◽  
Laminar Flame ◽  
Mixture Fraction ◽  
Leading Edge ◽  
Tangential Component ◽  
Flame Speed ◽  
Axial Position ◽  
Stoichiometric Mixture ◽  
Jet Mixing ◽  
Flame Curvature

The propagation of H2-enriched CH4-air triple flames in a nonpremixed jet is investigated numerically. The flames are ignited in a nonuniform jet-mixing layer downstream of the burner. A comprehensive, time-dependent computational model is used to simulate the transient ignition and flame propagation phenomena. The model employs a detailed description of methane-air chemistry and transport properties. Following ignition a well-defined flame is formed that propagates upstream towards the burner along the stoichiometric mixture fraction line. As the flame propagates upstream, the flame speed, which is defined as the normal flamefront velocity at the leading edge with respect to the local gas velocity, increases above or decreases below to the corresponding unstretched laminar flame speed of the stoichiometric planar premixed flame. Although the flame curvature varies as a function of axial position, the flame curvature remains nearly constant for a given flame. As hydrogen is added to the fuel stream the flame curvature during flame propagation remains nearly constant. During the flame propagation process, the hydrodynamic stretch dominates over the curvature-induced stretch. Hydrogen increases the heat release and the component of the velocity perpendicular to the flame increases across the surface, whereas the tangential component remains unchanged. This jump in the perpendicular velocity component bends the velocity vector toward the stoichiometric mixture fraction line. This redirection of the flow is accommodated by the divergence of the streamlines ahead of the flame, resulting in the decrease of the velocity and increase in the hydrodynamic stretch.

Characterization of the Viscosity of Blends of Dimethyl Ether With Various Fuels and Additives

2003 ◽  
Author(s):  
Shirish Bhide ◽  
David Morris ◽  
Jonathan Leroux ◽  
Kimberly S. Wain ◽  
Joseph M. Perez ◽  
...  
Keyword(s):  
Dimethyl Ether ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Mixture Fraction ◽  
Capillary Viscometer ◽  
Limiting Factor ◽  
Low Viscosity ◽  
Blend Ratios ◽  
Low Sulfur

Dimethyl ether (DME) is a potential ultra clean diesel fuel. Dimethyl ether burns without producing the smoke associated with diesel combustion and can be manufactured from synthesis gas or methanol. However, DME has a low viscosity compared to diesel fuel and has insufficient lubricity to prevent exc essive wear in fuel injection systems. One strategy to utilize DME is to blend it with diesel fuel to obtain cleaner burning fuels that retain satisfactory fuel properties. In the present work, the viscosity of blends of DME and various fuels and additives was characterized, including a federal low sulfur fuel, soybean oil, biodiesel and various lubricity additives, over a range of blend ratios. A methodology was developed to utilize a high pressure capillary viscometer to measure the viscosity of pure DME and blends of DME and other compounds in varying proportions and at pressures up to 3500 psig. While DME is miscible in diesel fuel at any mixture fraction when the blend is held under pressures of 75 psi or above, the viscosity of the blends is below the ASTM diesel fuel specification for even a 25 wt.% blend of DME in diesel fuel. None of the additives or fuels provides adequate viscosity when blended with DME unless the blend contains less than 50% DME. Viscosity, rather than lubricity, may be the limiting factor in utilizing DME.

Effect of stoichiometric mixture fraction on nonpremixed H2O2N2 edge-flames

2019 ◽  
Vol 37 (2) ◽  
pp. 1989-1996 ◽  
Author(s):  
Zhenghong Zhou ◽  
Siena S. Applebaum ◽  
Paul D. Ronney
Keyword(s):  
Mixture Fraction ◽  
Stoichiometric Mixture ◽  
Edge Flames

Simulation and Experimental Research on Species in Direct-Injection Diesel Engine

2014 ◽  
Vol 577 ◽  
pp. 244-247
Author(s):  
Yong Feng Liu ◽  
Hong Sen Tian ◽  
Xiao She Jia ◽  
Pu Cheng Pei ◽  
Yong Lu
Keyword(s):  
Diesel Engine ◽  
Mixture Fraction ◽  
Direct Injection ◽  
Three Dimension ◽  
Stoichiometric Mixture ◽  
Flamelet Model ◽  
Direct Injection Diesel Engine ◽  
Numerical Effort ◽  
Turbulent Flow Field ◽  
Coordinates Transformation

To simulate the combustion species for direct-injection diesel engines, the new flamelet model is presented and used. The model is based on stoichiometric mixture fraction space, and a way of separating the numerical effort associated with the solution of the turbulent flow field from that of solving the chemistry is offered. The new species equations are carried out through coordinates transformation. The results from the species equation are developed and three-dimension entity model with the mixture fraction is got. Then the boundary conditions are put into the new flamelet model. Furthermore the pollutions emissions are calculated and compared with the experimental data. It gives a new way to predict the pollutants for direct-injection diesel engine.

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