The Effect of Ambient Conditions on the Burning Rate of Gel Fuel Droplets

2012 ◽  
Vol 38 (2) ◽  
pp. 199-203 ◽  
Author(s):  
Dory Bar-or ◽  
Benveniste Natan
Keyword(s):  
Burning Rate ◽  
Ambient Conditions ◽  
Fuel Droplets

scholarly journals Interactive Effects in Two-Droplets Combustion of RP-3 Kerosene under Sub-Atmospheric Pressure

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1229
Author(s):  
Hongtao Zhang ◽  
Zhihua Wang ◽  
Yong He ◽  
Jie Huang ◽  
Kefa Cen
Keyword(s):  
Burning Rate ◽  
Atmospheric Pressure ◽  
High Speed ◽  
Ambient Pressure ◽  
Interactive Effects ◽  
Propagation Time ◽  
High Speed Camera ◽  
Single Droplet ◽  
Fuel Droplets ◽  
Spacing Distance

To improve our understanding of the interactive effects in combustion of binary multicomponent fuel droplets at sub-atmospheric pressure, combustion experiments were conducted on two fibre-supported RP-3 kerosene droplets at pressures from 0.2 to 1.0 bar. The burning life of the interactive droplets was recorded by a high-speed camera and a mirrorless camera. The results showed that the flame propagation time from burning droplet to unburned droplet was proportional to the normalised spacing distance between droplets and the ambient pressure. Meanwhile, the maximum normalised spacing distance from which the left droplet can be ignited has been investigated under different ambient pressure. The burning rate was evaluated and found to have the same trend as the single droplet combustion, which decreased with the reduction in the pressure. For every experiment, the interactive coefficient was less than one owing to the oxygen competition, except for the experiment at L/D0 = 2.5 and P = 1.0 bar. During the interactive combustion, puffing and microexplosion were found to have a significant impact on secondary atomization, ignition and extinction.

Effects of droplet diameter on instantaneous burning rate of isolated fuel droplets in argon-rich or carbon dioxide-rich ambiences under microgravity

2013 ◽  
Vol 34 (1) ◽  
pp. 1601-1608 ◽  
Author(s):  
Shinji Nakaya ◽  
Kotaro Fujishima ◽  
Mitsuhiro Tsue ◽  
Michikata Kono ◽  
Daisuke Segawa
Keyword(s):  
Carbon Dioxide ◽  
Burning Rate ◽  
Droplet Diameter ◽  
Fuel Droplets

Dynamics of Intermittent Sprays

1999 ◽  
Author(s):  
Badih A. Jawad
Keyword(s):  
Droplet Size ◽  
Droplet Size Distribution ◽  
Sampling Technique ◽  
Size Distributions ◽  
Ambient Conditions ◽  
Spray Formation ◽  
Fuel Droplets ◽  
Liquid Immersion ◽  
Particle Sizer ◽  
Droplet Size Distributions

Abstract It is considered that droplet size distribution changes with time and space, since diesel fuel sprays are found to be transient and intermittent due to variations in ambient pressures. Therefore the obscuration signal (extinction of light due to particle field) obtained from a particle sizer for a single injection of fuel over the whole region of spray is necessary to determine the spray characteristics. Previous studies dealing with sprays have observed fuel droplets by use of the sedimentation tower method or liquid immersion sampling technique. However, in these technique droplets are usually sampled after spray formation is complete. The completion time of spray formation appears to vary with ambient conditions, thus making spray measurements under transient conditions during injection difficult. It is the objective of this paper to shine some light on the dynamics of spray motion, leading to a better understanding of the droplet size distributions.

Experimental and Numerical Study of Spray Ignition for In-Flight Re-Light

2002 ◽  
Author(s):  
K. Lavergne ◽  
V. Quintilla ◽  
R. Lecourt ◽  
G. Lavergne
Keyword(s):  
Combustion Chamber ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Phase Flow ◽  
Ambient Conditions ◽  
Two Phase ◽  
Fuel Droplets ◽  
Experimental Configuration ◽  
Spark Plug ◽  
Simple Geometry

The context of this study is the prediction of re-ignition for turbojet engines after in-flight extinction at high altitude. Experiments have been performed on a simple geometry of a combustion chamber to test ignition at ambient conditions for three positions of the spark plug. Then, the two-phase flow corresponding to the experimental configuration has been simulated with the eulerian-lagrangian code used at ONERA. In parallel, a time dependent 0-dimensional model has been developed to predict the ignition of a cluster composed of fuel droplets when it is submitted to the spark inside the combustion chamber. This model has been applied on the two-phase flow computation in three elementary volumes located close to different spark plug positions. Ignition has been tested numerically for these clusters of drops, whose characteristics are dependent of their location in the combustion chamber, as well as, of the two-phase flow configuration in the geometry. Comparisons between experimental and numerical results are presented in this paper.

Study on Burning Characteristics of Small-Scale Ethanol Pool Fire in Closed and Open Space Under Low Air Pressure

2011 ◽  
Author(s):  
Yi Zeng ◽  
Jun Fang ◽  
Ran Tu ◽  
Jinjun Wang ◽  
Yongming Zhang
Keyword(s):  
Burning Rate ◽  
Open Space ◽  
Flame Temperature ◽  
Pool Fire ◽  
Air Pressure ◽  
Small Scale ◽  
Pulsation Frequency ◽  
Pool Fires ◽  
Closed Space ◽  
Ambient Conditions

This paper presents results of different burning rates of small-scale ethanol pool fires at pressures of 0.6∼1.0 atm in closed and open space. Experiments were performed using a square burner of side length of 4 cm under two different conditions: one was taken in a closed low air pressure cabin (0.5 m3, the interior pressure ranges from 0.6–1.0 atm); another was taken in open space respectively in Hefei (air pressure: 1.0 atm) and Lhasa (air pressure: 0.66 atm). The pool fire characteristics including the burning rate, the axial temperature and pulsation frequency of flame were measured. In closed space, the burning rate, flame temperature, and pulsation frequency of small-scale ethanol pool fires decreased with the decreasing pressure, while in open space they increased when the air pressure reduced. As a result of different ambient conditions and oxygen depletion, the burning rate, flame temperature and pulsation frequency were lower at lower air pressure in closed space but were higher at higher air pressure in open space.

Combustion of a Fuel Droplet Surrounded by Oxidizer Droplets

1991 ◽  
Vol 113 (4) ◽  
pp. 959-965 ◽  
Author(s):  
Tsung Leo Jiang ◽  
Huei-Huang Chiu
Keyword(s):  
Burning Rate ◽  
Droplet Size ◽  
Size Ratio ◽  
Group Effect ◽  
Fuel Droplet ◽  
Method Of Images ◽  
Fuel Droplets ◽  
Combustion Modes ◽  
Nonspherical Shape ◽  
Positive Effect

The interaction between a burning fuel droplet and satellite oxidizer droplets is studied analytically. The effects of droplet spacing and droplet size ratio on the flame configuration of a burning fuel droplet with a satellite oxidizer droplet are analyzed in a high-temperature oxidizing environment by using the bispherical coordinate system. Three combustion modes including normal combustion, conjugate combustion, and composite combustion are identified at appropriate droplet size ratio and droplet spacing. The burning rate of the fuel droplet is found to be greater than that of an isolated burning fuel droplet, and to increase with the decreasing distance between two droplets. This result has shown a positive effect on the interaction between fuel and oxidizer droplets, in contrast to that of two interacting fuel droplets where the burning rate decreases with decreasing droplet spacing. The combustion configuration of a fuel droplet surrounded by six satellite oxidizer droplets symmetrically is also examined by the method of images. The flame that encloses the fuel droplet is found to be “compressed” and distorted to a nonspherical shape due not only to the group effect among oxidizer droplets but also to the interaction of bipropellant droplets. The results indicate that the burning rate of a fuel droplet increases and the flame size decreases significantly as a result of an increased supply of oxidizer vapor provided by the surrounding oxidizer droplets. Therefore properly optimized bipropellant combustion is potentially able to achieve a desired combustion performance with a much smaller combustor than a conventional spray burner.

The Combustion Characteristics of n-Decane/Iso-Octane/Toluene Mixture and Jet-A Fuel Droplets in the Absence of Convection

2011 ◽  
Author(s):  
Yu-Cheng Liu ◽  
Anthony J. Savas ◽  
C. Thomas Avedisian
Keyword(s):  
Burning Rate ◽  
Droplet Diameter ◽  
Mixture Fraction ◽  
Combustion Characteristics ◽  
Aviation Fuel ◽  
Ternary Blend ◽  
Transportation Fuel ◽  
Spherical Droplet ◽  
Burning Process ◽  
Fuel Droplets

This study examines the extent to which a ternary mixture of n-decane/iso-octane/toluene in the specific mixture fraction of 42.67/33.02/24.31 (mole fraction), respectively, can replicate the droplet burning characteristics of an aviation fuel, Jet-A (designated by the Air Force as “POSF4658”). Experiments were carried out to examine the droplet combustion characteristics in an environment which minimizes convection to promote spherical symmetry in the burning process. The evolution of droplet diameter, burning rate and flame and soot stand-off ratios were compared to Jet-A to evaluate the potential of this ternary to serve as a Jet-A surrogate regarding the droplet burning process. The results show that the ternary blend has a shorter transient droplet heating period than Jet-A and it closely replicates the evolution of droplet diameter and burning rate. The burning rates for these two fuels are close at the end of burning, and flame and soot standoff ratios for the ternary are also reasonably close to those of Jet-A. The results also suggest that the spherical droplet flame configuration can be a useful tool to evaluate the extent to which a mixture of single component fuels may serve as a surrogate of a real transportation fuel.

Hydrogen bonding in liquid methanol at ambient conditions and at high pressure

2000 ◽  
Vol 98 (3) ◽  
pp. 125-134 ◽  
Author(s):  
T. Weitkamp, J. Neuefeind, H. E. Fisch
Keyword(s):  
High Pressure ◽  
Hydrogen Bonding ◽  
Ambient Conditions
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