High speed camera

Radiographic system with high speed camera... 

The second category includes BLEVE simulation, in which a pressurized, heated flask containing liquid or liquefied fuel is broken after the desired vapor pressure has been reached, and the released vapor is then ignited. Measurement of fireball diameter, liftoff time, combustion duration, and final height is captured by filming with high-speed cameras. Radiometers are used to measure radiation and temperature is measured by thermocouples or by determination of fireball color temperature (Lihou and Maund 1982). 

Fay and Lewis (1977) used spherical gas samples inside soap bubbles whose volumes ranged from 20 to 190 cm. Typically, a sphere was ignited with resistance wire, and the combustion process was then filmed with a high-speed camera. The fireball s maximum height and diameter, as well as the time needed to complete combustion, were evaluated. The fireball s thermal radiation was sensed by a radiation detector. Figure 6.3 relates fireball burning time and size to initial propane... 

Figure 3.2.1 shows flame kernels of the schlieren photograph taken by a high-speed camera. These photographs can be compared with the calculated temperature distribution in Figure 3.2.4. As can be seen, both of them bear a close resemblance. From this result, the authors firmly believe that the numerical simulation is a significant tool for grasping the mechanism of spark ignition. Of course, the experimental work should also be of importance to verify the results obtained by numerical simulations. In this work, the authors mainly introduce the results of numerical simulations that have been obtained xmtil then in their laboratory.

Schlieren photograph of flame kernels by a high-speed camera. Time is given from the onset of spark discharge in microseconds. Spark electrode diameter 0.2 mm spark gap width 1mm. 

There are many nonintrusive experimental tools available that can help scientists to develop a good picture of fluid dynamics and transport in chemical reactors. Laser Doppler velocimetry (LDV), particle image velocimetry (PIV) and sonar Doppler for velocity measurement, planar laser induced fluorescence (PLIF) for mixing studies, and high-speed cameras and tomography are very useful for multiphase studies. These experimental methods combined with computational fluid dynamics (CFDs) provide very good tools to understand what is happening in chemical reactors. 

Plate I. Typical high-speed camera photograph. The detonation velocity is 4,850 m./sec. The diagram shows the arrangement of the explosive and camera and the method of interpretation... 

From similar space-time high-speed camera studies of the shock initiation to detonation of NMe, Cook et al (Ref 9) observed a flasb-across phenomenon in which, an apparent wave of luminescence originated in the explosive behind the initial compression front and propagated at a reported velocity of 35 mm/ftsec to overtake the initial compression front. This "flash, across phenomenon was interpreted as a heat transfer wave caused by a sudden increase in the thermal conductivity of the shock-compressed NMe. The phenomenon was taken as a direct observation of the "heat pulse , which Cook et al had predicted in 1955 (Ref 2)... 

High-speed photography provides the main observational facility in the study and measurement of explosive phenomena. In Vol 2, pp Cl3-19, many high-speed cameras are described... 

High speed cameras reveal that initiation of expln in liquid and many of the solid expls. 

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