The images shown are photographs of ethylene/air/nitrogen diffusion flames stabilized behind a bluff centerbody. The two images on the top show the centerbody flame photographed from the side (top left) and top views (top right). The blue regions are associated with the flame front and the other colors of the flame are largely due to blackbody radiation from the soot. The intense yellow radiation is from soot trapped in a tight ring vortex downstream of the stabilizing bluff body. The motion of the soot trapped in the vortex can be seen in the longer exposure photograph taken from the top.
The bottom two images are of a centerbody flame with the same inlet flow velocities as the case shown above but with higher nitrogen content in the feed gases. The image on the lower left shows a blue ring flame that forms around the main flame immediately downstream of the centerbody. This blue ring flame exhibits a slight oscillation in the vertical direction. The image on the lower right shows the region downstream of the ring flame for the same conditions. The disturbances in the downstream region of the flame are amplified as it passes through the tube, resulting in the large structures shown in the short exposure (0.8 ms) photo.
Credit: Scott Stouffer, Garth Justinger (University of Dayton Research Institute), Mel Roquemore, Amy Lynch, Vince Belovich, Joe Zelina, Jim Gord (Air Force Research Laboratory, Wright Patterson Air Force Base), Keith Grinstead, Vish Katta and Kyle Frische (Innovative Scientific Solutions Incorporated)
This is an image of a spherical diffusion flame of ethylene burning in air in the NASA GRC 2.2 s drop tower. The image was recorded about 1.4 s after ignition. The ethylene flowrate is 1.5 mg/s and the scale is revealed by the 6.5 mm porous sphere visible in the image. The image was recorded using a Nikon D100 digital single-lens reflex camera with a 125 ms exposure.
Credit: P.B. Sunderland (University of Maryland), D.L. Urban and D.P. Stocker (NASA Glenn Research Center), B.H. Chao (University of Hawaii) and R.L. Axelbaum (Washington University)
This image shows a ternary flame system with a Santoro burner below a ring burner. The steady soot column generated by the acetylene diffusion flame passes into the hydrogen ring flame, where it is oxidized. This allows soot oxidation to be studied in the absence of soot formation. The camera is a Nikon D100 digital still camera at 6.1 megapixels. This research is supported by NSF.
Credit: H. Guo, P.M. Anderson, P.B. Sunderland (University of Maryland)
If you’ve ever wondered what else you can do with multiple exposure, the ethereal, Impressionist-inspired works of a Finnish artist and photographer might in turn be inspirational for you. Find out more after the jump!