scholarly journals Laser-Induced Ignition and Combustion of Individual Aluminum Particles Below 10 μm by Microscopic High-Speed Cinematography

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 280 ◽  
Author(s):  
Fengting Hou ◽  
Shengji Li ◽  
Yue Wang ◽  
Xuefeng Huang
Keyword(s):  
Direct Observation ◽  
High Speed ◽  
Combustion Mechanism ◽  
Aluminum Particles ◽  
Experimental Apparatus ◽  
High Speed Cinematography ◽  
Metal Aluminum ◽  
Induced Ignition ◽  
Combustion Behaviors ◽  
Ignition And Combustion

Metal aluminum has been widely used as an ingredient in propellant, gunpowder and thermite, but there is less understanding of the combustion mechanism of aluminum particles from submicron to several microns in diameter. This paper proposes to experimentally investigate the ignition and combustion characteristics of individual aluminum particles below 10 μm. A specific in situ diagnostic experimental apparatus was first designed for directly observing the ignition and combustion behaviors of individual aluminum particles, with a submicrometer spatial resolution and a temporal resolution of tens of microseconds. Direct observation through microscopic high-speed cinematography demonstrated that, when heated by a continuous laser, individual aluminum particles thermally expanded, followed by shell rupture; the molten aluminum core overflowed and evaporated, leading to ignition and combustion. Further results showed that, when the laser power densities were gradually increased (5.88, 7.56 and 8.81 × 105 W/cm2), the durations of thermal expansion, melting and evaporation were shortened. The required time for the aluminum particles to expand to 150% of their initial diameter was shortened (34 s, 0.34 s and 0.0125 s, respectively). This study will be beneficial to further extend the investigation of other individual metal particles and reveal their combustion mechanism by direct observation.

scholarly journals Combustion of Laser-Induced Individual Magnesium Microparticles under Natural Convection

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1276
Author(s):  
Chengyuan Lin ◽  
Minqi Zhang ◽  
Yue Wang ◽  
Shengji Li ◽  
Xuefeng Huang ◽  
...  
Keyword(s):  
Gas Phase ◽  
High Speed ◽  
Dominant Role ◽  
Combustion Process ◽  
Particle Diameter ◽  
Combustion Model ◽  
Combustion Mechanism ◽  
Rocket Propellants ◽  
High Speed Cinematography ◽  
Ignition And Combustion

Metal magnesium (Mg) fuels have been widely used in rocket propellants. The combustion study on individual Mg microparticles is crucial to the in-depth unveiling of the combustion mechanism of Mg-based propellants. In this paper, a new experimental setup was proposed to directly observe the combustion of individual micron-sized Mg particles, based on laser ignition and microscopic high-speed cinematography. The combustion process of individual Mg microparticles could be directly and clearly observed by the apparatus at high temporal and spatial resolutions. Individual Mg microparticles took gas phase combustion, and mainly underwent four stages: expansion, melting, gasification, ignition, and combustion. The ignition delay time and total combustion time had an exponential decay on the particle diameter, and they had a linear decay on the ignition power density. The melting took a dominant role in the whole burnout time. The gas-phase combustion flame seemed thick, inhomogeneous, and ring-like structure. The combustion model of individual Mg microparticles was built through combining the experimental results with the SEM, XRD, XPS, and EDS analysis of original samples and combustion residues. This study will be beneficial to understand the combustion process and reveal the combustion mechanism of metal microparticles besides Mg.

Ignition and combustion mechanism in aluminum particles

1977 ◽  
Vol 12 (2) ◽  
pp. 177-182 ◽  
Author(s):  
A. A. Razdobreev ◽  
A. I. Skorik ◽  
Yu. V. Frolov
Keyword(s):  
Combustion Mechanism ◽  
Aluminum Particles ◽  
Ignition And Combustion

Ignition and Combustion Behaviors of Nanocomposite Al/MoO3

2003 ◽  
Vol 800 ◽  
Author(s):  
John J. Granier ◽  
Michelle L. Pantoya
Keyword(s):  
Combustion Wave ◽  
High Speed ◽  
Initial Sample ◽  
High Speed Imaging ◽  
Wave Speeds ◽  
Nano Scale ◽  
Pellet Density ◽  
Scale Particle ◽  
Combustion Behaviors ◽  
Ignition And Combustion

ABSTRACTFlame propagation in Al/MoO3 thermites is measured as a function of bulk density and initial sample temperature. The composites are composed of nano-scale reactant particles mixed and pressure molded to between 49 and 73% of the theoretical maximum density. A relationship between cylindrical die pressure and final pellet density is derived. Experiments are also performed by initially pre-heating samples to a uniform temperature ranging from 20 to 200 °C. Ignition sensitivity was determined by measuring the ignition delay time and temperature using a 50-W CO2 laser and thermocouples, respectively. Combustion wave speeds were measured using high-speed imaging diagnostics. Results allow comparison of combustion behaviors associated with nano- vs. micron-scale particle composites. The nano-scale particle composites are extremely sensitive to ignition, especially when initially preheated. Combustion wave speeds for the compressed nano-composites were found to double when compared to the micron-scale composites.

scholarly journals Vaporization, Diffusion and Combustion of Laser-Induced Individual Magnesium Microparticles in Inert and Oxidizing Atmospheres

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2057
Author(s):  
Fan Yang ◽  
Shengji Li ◽  
Xunjie Lin ◽  
Jiankan Zhang ◽  
Heping Li ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
High Speed ◽  
Diffusion Rate ◽  
Normal Pressure ◽  
Inert Gases ◽  
Oxide Thin Film ◽  
Pure Oxygen ◽  
High Speed Cinematography ◽  
Porous Magnesium ◽  
Combustion Behaviors

Although the gas phase combustion of metallic magnesium (Mg) has been extensively studied, the vaporization and diffusive combustion behaviors of Mg have not been well characterized. This paper proposes an investigation of the vaporization, diffusion, and combustion characteristics of individual Mg microparticles in inert and oxidizing gases by a self-built experimental setup based on laser-induced heating and microscopic high-speed cinematography. Characteristic parameters like vaporization and diffusion coefficients, diffusion ratios, flame propagation rates, etc., were obtained at high spatiotemporal resolutions (μm and tens of μs), and their differences in inert gases (argon, nitrogen) and in oxidizing gases (air, pure oxygen) were comparatively analyzed. More importantly, for the core–shell structure, during vaporization, a shock wave effect on the cracking of the porous magnesium oxide thin film shell-covered Mg core was first experimentally revealed in inert gases. In air, the combustion flame stood over the Mg microparticles, and the heterogeneous combustion reaction was controlled by the diffusion rate of oxygen in air. While in pure O2, the vapor-phase stand-off flame surrounded the Mg microparticles, and the reaction was dominated by the diffusion rate of Mg vapor. The diffusion coefficients of the Mg vapor in oxidizing gases are 1~2 orders of magnitude higher than those in inert gases. However, the diffusive ratios of condensed combustion residues in oxidizing gases are ~1/2 of those in inert gases. The morphology and the constituent contents analysis showed that argon would not dissolve into liquid Mg, while nitrogen would significantly dissolve into liquid Mg. In oxidizing gases of air or pure O2, Mg microparticles in normal pressure completely burned due to laser-induced heating.

scholarly journals Ignition and combustion mechanism in a prechamber combustor (Quantitative classification of combustion patterns)

1986 ◽  
Vol 52 (482) ◽  
pp. 3609-3615
Author(s):  
Norio OHIWA ◽  
Shigeki YAMAGUCHI ◽  
Tatsuya HASEGAWA ◽  
Motokazu OGISO
Keyword(s):  
Combustion Mechanism ◽  
Quantitative Classification ◽  
Ignition And Combustion

Direct observation of surfactant aggregate behavior on a mica surface using high-speed atomic force microscopy

2011 ◽  
Vol 47 (17) ◽  
pp. 4974 ◽  
Author(s):  
Shigeto Inoue ◽  
Takayuki Uchihashi ◽  
Daisuke Yamamoto ◽  
Toshio Ando
Keyword(s):  
Atomic Force Microscopy ◽  
Direct Observation ◽  
High Speed ◽  
Mica Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Aggregate Behavior

New findings on life history traits of Xenos peckii (Strepsiptera: Xenidae)

2014 ◽  
Vol 146 (5) ◽  
pp. 514-527 ◽  
Author(s):  
M. Hrabar ◽  
A. Danci ◽  
S. McCann ◽  
P.W. Schaefer ◽  
G. Gries
Keyword(s):  
Life History ◽  
High Speed ◽  
Life History Traits ◽  
Suture Line ◽  
Paper Wasp ◽  
Anterior Portion ◽  
New Findings ◽  
High Speed Cinematography ◽  
Normal Speed ◽  
Wasp Nests

AbstractWe studied life history traits of Xenos peckii Kirby (Strepsiptera: Xenidae), a little-known parasite of the paper wasp Polistes fuscatus (Fabricus) (Hymenoptera: Vespidae) in North America. We field-collected 24 wasp nests in early July 2012, isolated parasitised wasps, tracked life history events of X. peckii, and recorded such behaviour as emergence of males and mating by normal-speed and high-speed cinematography. To emerge, males first cut the puparium with their mandibles along an ecdysial suture line, and then push aside the pupal cap during emergence. The endoparasitic females engage in active calling (pheromone release) behaviour by slowly inflating their cephalothorax, and then extruding it even farther out of, and tilting it away from, the host wasp abdomen. Seasonal and diel (afternoon) emergence periods of males coincide with seasonal and diel receptivity and calling periods of females. Males approach calling females in a swaying flight with smooth turns. They typically land on the anterior portion of the host wasp's abdomen, and then step backward until they make contact with the cephalothorax of the female. As soon as their mesothoracic legs contact the female's cephalothorax, they curl around it, and the male initiates mating. Thereafter, the female fully retreats and never re-mates.

Angular Momentum Requirements of the Twisting and Nontwisting Forward 1 1/2 Somersault Dive

1987 ◽  
Vol 3 (1) ◽  
pp. 47-62 ◽  
Author(s):  
Ross H. Sanders ◽  
Barry D. Wilson
Keyword(s):  
Angular Momentum ◽  
High Speed ◽  
Center Of Gravity ◽  
Transverse Axis ◽  
Free Position ◽  
High Speed Cinematography ◽  
The Difference ◽  
Hip Flexion ◽  
Commonwealth Games

This study investigated the in-flight rotation of elite 3m springboard divers by determining the angular momentum requirement about the transverse axis through the divers center of gravity (somersault axis) required to perform a forward 1 1/2 somersault with and without twist. Three elite male divers competing in the 1982 Commonwealth Games were filmed using high-speed cinematography while performing the forward 1 1/2 somersault in the pike position and the forward 1 1/2 somersault with one twist in a free position. The film was digitized to provide a kinematic description of each dive. An inclined axis technique appeared to be the predominant means of producing twist after takeoff from the board. The angular momentum about the somersault axis after takeoff was greater for the forward 1 1/2 somersault with twist than the forward 1 1/2 somersault without twist for all three divers. The difference in angular momentum between the two dives of each diver ranged from 6% to 19%. The most observable difference between the dives during the preflight phases was the degree of hip flexion at takeoff. There was more hip flexion at takeoff in 5132D than 103B for all three divers. This difference ranged from 9° to 18° (mean = 14°).

Kinematics of Tongue Projection in Chamaeleo Oustaleti

1991 ◽  
Vol 159 (1) ◽  
pp. 109-133 ◽  
Author(s):  
PETER C. WAINWRIGHT ◽  
DAVID M. KRAKLAU ◽  
ALBERT F. BENNETT
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Maximum Velocity ◽  
Head Movements ◽  
Florida State University ◽  
State University ◽  
Maximum Acceleration ◽  
Related Family ◽  
High Speed Cinematography ◽  
Tongue Movements

The kinematics of prey capture by the chamaeleonid lizard Chamaeleo oustaleti were studied using high-speed cinematography. Three feeding sequences from each of two individuals were analyzed for strike distances of 20 and 35 cm, at 30°C. Ten distances and angles were measured from sequential frames beginning approximately 0.5 s prior to tongue projection and continuing for about 1.0 s. Sixteen additional variables, documenting maximum excursions and the timing of events, were calculated from the kinematic profiles. Quantified descriptions of head, hyoid and tongue movements are presented. Previously unrecognized rapid protraction of the hyobranchial skeleton simultaneously with the onset of tongue projection was documented and it is proposed that this assists the accelerator muscle in powering tongue projection. Acceleration of the tongue occurred in about 20ms, reaching a maximum acceleration of 486 m s−2 and maximum velocity of 5.8m s−1 in 35 cm strikes. Deceleration of the tongue usually began within 5 ms before prey contract and the direction of tongue movement was reversed within 10 ms of prey contact. Retraction of the tongue, caused by shortening of the retractor muscles, reached a maximum velocity of 2.99 ms−1 and was complete 330 ms after prey contact. Projection distance influences many aspects of prey capture kinematics, particularly projection time, tongue retraction time and the extent of gape and head movements during tongue retraction, all of which are smaller in shorter feedings. Though several features of the chameleon strike have apparently been retained from lizards not capable of ballistic tongue projection, key differences are documented. Unlike members of a related family, the Agamidae, C. oustaleti uses no body lunge during prey capture, exhibits gape reduction during tongue projection and strongly depresses the head and jaws during tongue retraction. Note: Present address: Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, USA.

Improvement of ignition and combustion performance of micro-aluminum particles by double-shell nickel-phosphorus alloy coating

2021 ◽  
pp. 133585
Author(s):  
Chao Wang ◽  
Xiangrui Zou ◽  
Shipan Yin ◽  
Junlong Wang ◽  
Hongyang Li ◽  
...  
Keyword(s):  
Alloy Coating ◽  
Aluminum Particles ◽  
Combustion Performance ◽  
Ignition And Combustion ◽  
Phosphorus Alloy
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