Measurements of Laminar Flame Speeds of Gas-to-Liquid-Diesel Fuel Blends

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Samahat Samim ◽  
Abdellatif M. Sadeq ◽  
Samer F. Ahmed

This work investigates the laminar flame speed, SN, of gas-to-liquid (GTL) fuel and its 50–50% by volume blends with conventional diesel, in a cylindrical bomb capable of measuring SN at different initial temperatures and equivalence ratios at ambient pressure. SN was measured by analysing the pressure signals after combustion detected by a pressure transducer mounted on the bomb. Direct visualization has also been conducted to observe the ignition and flame propagation. It was found that pure GTL fuel has the highest SN near stoichiometric conditions, which is about 88.3 cm/s. However, at lean and rich mixtures, SN of GTL is slightly lower than that of the conventional diesel. The blended fuel has the lowest SN at lean and rich mixture conditions comparing with those of GTL and diesel fuels. Studying the effect of increasing the initial temperature on SN revealed that SN of the three tested fuels increases with the increase in the initial temperature almost linearly. However, the blended fuel has the lowest SN at the highest temperature, about 89.7 cm/s at 250 °C.

Author(s):  
Juan Pablo Gomez Montoya ◽  
Andres Amell

Abstract A novel methodology is proposed to evaluate fuel´s performance in spark ignition (SI) engines based on the fuel´s energy quality and availability to produce work. Experiments used a diesel engine with a high compression ratio (CR), modified by SI operation, and using interchangeable pistons. The interchangeable pistons allowed for the generation of varying degrees of turbulence during combustion, ranging from middle to high turbulence. The generating efficiency (ηq), and the maximum electrical energy (EEmax) were measured at the knocking threshold (KT). A cooperative fuel research (CFR) engine operating at the KT was also used to measure the methane number (MN), and critical compression ratio (CCR) for gaseous fuels. Fuels with MNs ranging from 37 to 140 were used: two biogases, methane, propane, and five fuel blends of biogas with methane/propane and hydrogen. Results from both engines are linked at the KT to determine correlations between fuel´s physicochemical properties and the knocking phenomenon. Certain correlations between knocking and fuel properties were experimentally determined: energy density (ED), laminar flame speed (SL), adiabatic flame temperature (Tad), heat capacity ratio (γ), and hydrogen/carbon (H/C) ratio. Based on the results, a mathematical methodology for estimating EEmax and ηq in terms of ED, SL, Tad, γ, H/C, and MN is presented. These equations were derived from the classical maximum thermal efficiency for SI engines given by the Otto cycle efficiency (ηOtto). Fuels with MN > 97 got higher EEmax, and ηq than propane, and diesel fuels.


Fuel ◽  
2017 ◽  
Vol 203 ◽  
pp. 298-307 ◽  
Author(s):  
Reyes García-Contreras ◽  
Octavio Armas ◽  
Carmen Mata ◽  
Octavio Villanueva

2019 ◽  
Vol 37 (3) ◽  
pp. 236-256 ◽  
Author(s):  
Xuehui Wang ◽  
Tiannian Zhou ◽  
Qinpei Chen ◽  
Junjiang He ◽  
Zheng Zhang ◽  
...  

Liquid–vapor phase equilibrium theories are used to analyze boiling processes of blended fuel pool fires, and the results show that there are two boiling mechanisms (azeotropism and non-azeotropism) for blended fuels compared with single-component fuels. A series of pool fire experiments were conducted to investigate the combustion characteristics of blended fuel pool fires. The experimental results showed that the two boiling mechanisms have different effects on the burning process of the fuel blends. The boiling temperature and composition varied for the non-azeotropic blends during the burning process and remained steady for azeotropic blends. Furthermore, the boiling temperature of azeotropic blends is lower than that of its components and ranges from a specific temperature to the boiling point of the less volatile component. The flame radiant fraction of the azeotropic blend was also relatively constant during the burning process, whereas that of the non-azeotropic blend varied in different stages of the burning process. Heskestad’s flame height model and flame axial temperature distribution model are applicable for pool fires of azeotropic and non-azeotropic blends.


Energy ◽  
2012 ◽  
Vol 47 (1) ◽  
pp. 620-629 ◽  
Author(s):  
H.S. Tira ◽  
J.M. Herreros ◽  
A. Tsolakis ◽  
M.L. Wyszynski

Author(s):  
Sandra Richter ◽  
Jörn Ermel ◽  
Thomas Kick ◽  
Marina Braun-Unkhoff ◽  
Clemens Naumann ◽  
...  

Currently, new concepts for power generation are discussed, as a response to combat global warming due to CO2 emissions stemming from the combustion of fossil fuels. These concepts include new, low-carbon fuels as well as centralized and decentralized solutions. Thus, a more diverse range of fuel supplies will be used, with (biogenic) low-caloric gases such as syngas and coke oven gas (COG) among them. Typical for theses low-caloric gases is the amount of hydrogen, with a share of 50% and even higher. However, hydrogen mixtures have a higher reactivity than natural gas (NG) mixtures, burned mostly in today's gas turbine combustors. Therefore, in the present work, a combined experimental and modeling study of nitrogen-enriched hydrogen–air mixtures, some of them with a share of methane, to be representative for COG, will be discussed focusing on laminar flame speed data as one of the major combustion properties. Measurements were performed in a burner test rig at ambient pressure and at a preheat temperature T0 of 373 K. Flames were stabilized at fuel–air ratios between about φ = 0.5–2.0 depending on the specific fuel–air mixture. This database was used for the validation of four chemical kinetic reaction models, including an in-house one, and by referring to hydrogen-enriched NG mixtures. The measured laminar flame speed data of nitrogen-enriched methane–hydrogen–air mixtures are much smaller than the ones of nitrogen-enriched hydrogen–air mixtures. The grade of agreement between measured and predicted data depends on the type of flames and the type of reaction model as well as of the fuel–air ratio: a good agreement was found in the fuel lean and slightly fuel-rich regime; a large underprediction of the measured data exists at very fuel-rich ratios (φ > 1.4). From the results of the present work, it is obvious that further investigations should focus on highly nitrogen-enriched methane–air mixtures, in particular for very high fuel–air ratio (φ > 1.4). This knowledge will contribute to a more efficient and a more reliable use of low-caloric gases for power generation.


2006 ◽  
Vol 20 (6) ◽  
pp. 2377-2384 ◽  
Author(s):  
A. Abu-Jrai ◽  
A. Tsolakis ◽  
K. Theinnoi ◽  
R. Cracknell ◽  
A. Megaritis ◽  
...  

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