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.

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.

scholarly journals Application of Rainbow Thermometry to the Study of Fuel Droplet Heat-Up and Evaporation Characteristics

1996 ◽  
Author(s):  
Subramanian V. Sankar ◽  
Dale H. Buermann ◽  
William D. Bachalo
Keyword(s):  
Vaporization Rate ◽  
Fuel Droplet ◽  
Controlled Experiments ◽  
Regression Rate ◽  
Droplet Vaporization ◽  
Fuel Droplets ◽  
Spray Flame ◽  
Polydisperse Flow ◽  
Phase Doppler Particle Analyzer

Advanced, non-intrusive, laser-based diagnostics are being developed for simultaneously measuring the size, velocity, temperature, and instantaneous regression rates of vaporizing/burning fuel droplets in polydisperse flow environments. The size and velocity of the droplets are measured using a conventional phase Doppler particle analyzer (PDPA), whereas the droplet temperatures are simultaneously measured with a rainbow thermometer. This integrated diagnostic has been applied to the study of fuel droplet heat-up characteristics in a swirl-stabilized kerosene spray flame. It has also been shown that a novel extension of rainbow thermometry can be used to additionally extract the instantaneous droplet vaporization rate. The feasibility of measuring the instantaneous regression rate has also been demonstrated using controlled experiments with a vaporizing/burning stream of ethanol droplets.

scholarly journals Systematic Measurement of Hydrocarbon Fuel Droplet Burning Rate Constants and Ignition Delays

2019 ◽  
Vol 35 (4) ◽  
pp. 690-703 ◽  
Author(s):  
John W. Bennewitz ◽  
Alireza Badakhshan ◽  
Douglas G. Talley
Keyword(s):  
Burning Rate ◽  
Rate Constants ◽  
Hydrocarbon Fuel ◽  
Systematic Measurement ◽  
Fuel Droplet

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

scholarly journals The ergogenic effect of beta-alanine combined with sodium bicarbonate on high-intensity swimming performance

2013 ◽  
Vol 38 (5) ◽  
pp. 525-532 ◽  
Author(s):  
Vitor de Salles Painelli ◽  
Hamilton Roschel ◽  
Flávia de Jesus ◽  
Craig Sale ◽  
Roger Charles Harris ◽  
...  
Keyword(s):  
Sodium Bicarbonate ◽  
Swimming Performance ◽  
Time Trial ◽  
Crossover Fashion ◽  
Group Effect ◽  
Time Trial Performance ◽  
Beta Alanine ◽  
To Receive ◽  
Positive Effect ◽  
Trial Performance

We investigated the effect of beta-alanine (BA) alone (study A) and in combination with sodium bicarbonate (SB) (study B) on 100- and 200-m swimming performance. In study A, 16 swimmers were assigned to receive either BA (3.2 g·day−1 for 1 week and 6.4 g·day−1 for 4 weeks) or placebo (PL; dextrose). At baseline and after 5 weeks of supplementation, 100- and 200-m races were completed. In study B, 14 were assigned to receive either BA (3.2 g·day−1 for 1 week and 6.4 g·day−1 for 3 weeks) or PL. Time trials were performed once before and twice after supplementation (with PL and SB), in a crossover fashion, providing 4 conditions: PL-PL, PL-SB, BA-PL, and BA-SB. In study A, BA supplementation improved 100- and 200-m time-trial performance by 2.1% (p = 0.029) and 2.0% (p = 0.0008), respectively. In study B, 200-m time-trial performance improved in all conditions, compared with presupplementation, except the PL-PL condition (PL-SB, +2.3%; BA-PL, +1.5%; BA-SB, +2.13% (p < 0.05)). BA-SB was not different from BA-PL (p = 0.21), but the probability of a positive effect was 78.5%. In the 100-m time-trial, only a within-group effect for SB was observed in the PL-SB (p = 0.022) and BA-SB (p = 0.051) conditions. However, 6 of 7 athletes swam faster after BA supplementation. The probability of BA having a positive effect was 65.2%; when SB was added to BA, the probability was 71.8%. BA and SB supplementation improved 100- and 200-m swimming performance. The coingestion of BA and SB induced a further nonsignificant improvement in performance.

Effects of fuel droplet size on soot formation in spray flames formed in a laminar counterflow

2011 ◽  
Vol 158 (12) ◽  
pp. 2559-2568 ◽  
Author(s):  
Jun Hayashi ◽  
Hiroaki Watanabe ◽  
Ryoichi Kurose ◽  
Fumiteru Akamatsu
Keyword(s):  
Droplet Size ◽  
Soot Formation ◽  
Fuel Droplet ◽  
Spray Flames

A Semi-Analytical Model for Evaporating Fuel Droplets

2005 ◽  
Vol 127 (2) ◽  
pp. 199-203 ◽  
Author(s):  
Achintya Mukhopadhyay ◽  
Dipankar Sanyal
Keyword(s):  
Gas Phase ◽  
Computational Cost ◽  
Lewis Number ◽  
Droplet Evaporation ◽  
Solution Procedure ◽  
Droplet Surface ◽  
Spray Combustion ◽  
Fuel Droplet ◽  
Cfd Model ◽  
Fuel Droplets

An algorithm for solution of a model for heating and evaporation of a fuel droplet has been developed. The objective of the work is to develop a computationally economic solution module for simulating droplet evaporation that can be incorporated in spray combustion CFD model that handles a large number of droplets. The liquid-phase transient diffusive equation has been solved semi-analytically, which involves a spatially closed-form and temporally discretized solution procedure. The model takes into account droplet surface regression, nonunity gas-phase Lewis number and variation of latent heat with temperature. The accuracy of the model is identical to a Finite Volume solution obtained on a very fine nonuniform grid, but the computational cost is significantly less, making this approach suitable for use in a spray combustion code. The evaporation of isolated heptane droplet in a quiescent ambient has been investigated for ambient pressures of 1 to 5 bar.

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