Microscopic spray measurements of non-reacting alternative jet fuel: Effect of ambient gas temperature

Fuel ◽  
2021 ◽  
Vol 294 ◽  
pp. 120467
Author(s):  
Kumaran Kannaiyan ◽  
Reza Sadr
Author(s):  
Kumaran Kannaiyan ◽  
Reza Sadr

Abstract In recent years, Gas-to-Liquid (GTL) jet fuel is considered as an alternative jet fuel because of its cleaner combustion characteristics. The chemical and physical properties of GTL fuels are different from those of the conventional jet fuels. The objective of the present work is to investigate the effect of ambient conditions and fuel volatilization characteristics on the macroscopic spray features. To this end, the macroscopic spray performance is visualized using the shadowgraph imaging technique at elevated ambient conditions. The near nozzle spray parameters like spray cone angle, sheet breakup length, and the sheet velocity, are determined from the shadowgraph images using an in-house program. The effect of ambient conditions on the near nozzle spray characteristics for conventional fuels has been reported in the literature. However, these effects have not been reported in detail for the alternative, GTL jet fuels. The results show that the ambient gas pressure has a significant effect on the spray performance when compared to that of the ambient gas temperature. At atmospheric conditions, the spray performance of GTL fuel is comparable to those of Jet A-1 fuel. However, with the increase in ambient conditions, the difference in spray performance of GTL and Jet A-1 is significant.


2019 ◽  
Author(s):  
Giacomo Flora ◽  
Shane T. Kosir ◽  
Lily Behnke ◽  
Robert D. Stachler ◽  
Joshua S. Heyne ◽  
...  

Author(s):  
Shigehisa Fukui ◽  
Fumiya Shinohara ◽  
Ryota Asada ◽  
Hiroshige Matsuoka

In the present paper, the flying characteristics of a step slider flying in either air or He with a local temperature distribution of the disk are analyzed using the thermo-molecular gas-film lubrication (t-MGL) equation in the quasi-free-molecular flow region (quasi-free-molecular t-MGL equation: t-MGLqfm eq.). The gas temperature in the t-MGLqfm equation, τG, is assumed to be that in the free molecular limit, τGfm, defined by temperatures and accommodation coefficients at the disk, τW0, α0, and those at the slider, τW1, α1, respectively. The decreases in static spacing for the slider flying in He are significant. Moreover, the spacing decreases as the accommodation coefficients of the disk, α0, decreases, that is, as the ratio of specular reflection increases. The spacing fluctuation caused by a running wavy disk varies according to both the ambient gas (air/He) and the boundary accommodation coefficients.


Author(s):  
Yifeng Wu ◽  
Ronghua Huang ◽  
Chia-fon F. Lee

Effects of fuel and ambient gas temperature on the spray and combustion characteristics of soybean biodiesel were studied in a constant-volume combustion chamber. Four different fuels or fuel blends including B0, B20, B50 and B100 were investigated experimentally. The soot mass data were obtained via a new technique called forward illumination light extinction (FILE). The ambient gas temperature was varied from 700 K to 1200 K. To simulate the engine operating conditions, the ambient oxygen concentration and its density were kept at 21 % and 15 kg/m3, respectively. A higher peak pressure is found as the biodiesel content decreases. B20, B50 and B100 have a shorter ignition delay than B0 and the ignition delay decreases with increasing biodiesel content. The liquid penetration decreases with decreasing biodiesel content. Moreover, the integrated natural flame luminosity (INFL) increases with decreasing biodiesel content. Shorter flame (i.e., soot luminosity) duration and a longer delay between start of combustion (SOC) and the appearance of flame are found as the biodiesel content increases. The flame duration also increases with increasing ambient gas temperature for all fuels. Soot is lower and appears later at a lower ambient gas temperature, while it is burned out at around the same time. Near-zero soot mass was observed for all tested fuels at 700 K. A shorter soot formation process is observed for biodiesel fuels. The soot reduction using B20 and B50 is not obvious compared to B0 at a low temperature. But under the ordinary diesel engine operating condition at 1000 K, the soot reduction is significant. It is also found that the soot can be reduced by 60% and above when B100 is used in this study.


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