Simultaneous measurement of three-dimensional flame contour and velocity field for characterizing the flickering motion of a dilute hydrogen flame

Abstract

In this paper, an experimental method for simultaneous measurement of three-dimensional flame contour and velocity field is described for characterizing the flickering motion of a dilute hydrogen flame. The three-dimensional flame contour is measured by three CCD cameras around the flame with a digital-image reconstruction technique, while the velocity field is measured simultaneously by a planar PIV technique, which is supported by flow visualization with a reactive Mie scattering method. The visualization result shows that the flame structure consists of an inner flame, where the tracers follow the fuel flow, and an outer surrounding flame, where the diffused fuel reacts with oxidants. It is also found that the velocity field varies periodically during the flickering motion of the flame, which is clearly observed near the top of the flame, oscillating vertically with a phase of the velocity field. These results suggest the usefulness of the present experimental technique.

Spatiotemporal flame mapping in a large-bore marine diesel engine using multiple high-speed cameras

“…The cameras were placed around a burner and at 120° apart, covering the whole field of view and providing six flame contours from which interpolating methods are applied in order to capture the surface of the flame. Similar multi-camera work can be found by Fujisawa and Nakashima, 60 Han et al 61 and Wang et al 62…”

Temperature measurement of dilute hydrogen flame by digital laser-speckle technique

“…It is expected that some deviations of temperature measurement in the outer region at z=10mm (Fig.11(b)) may be caused by the partial deterioration of axisymmetry of the flame. Such asymmetry of the flame has been observed by the presence of minor roughness at the fuel tube exit (Fujisawa and Nakashima 2007). It should be mentioned that the temperature distributions without concentration correction shows higher temperatures than those with correction, which is mainly contributed by the presence of H2 and He in the dilute hydrogen flame.…”

“…The volume fraction of hydrogen and helium is set to 6:4 in the present experiment. In order to avoid the flame flickering, a uniform co-flow of air is supplied to the test section through a honeycomb having an area of 120mmx120mm (Fujisawa and Nakashima 2007). Note that the surrounding co-flow velocity of air is 0.024m/s in the present experiment.…”

Imaging of flame behavior in flickering methane/air diffusion flames

“…Some of the previous studies include correlation of flame Regular Paper frequency with flow rate, gravitational forces and other effects as mentioned above Tools used included flame luminosity (Smyth et al, 1997), temperature measurements using thin-filament pyrometry (Pitts, 1996), flame visualization using three-dimensional characterization (Bheemul et al, 2002), measurements using Planar Laser Induced Fluorescence (PLIF), Laser Doppler Velocimetry (LDV) (Lingens et al 1996), photography and chemieluminescence from CH radicals (Hardalupas et al 1998), Mie Scattering (Chung, 2003), and PIV (Papadopoulos et al, 2002;Fujisawa and Nakashima, 2007), imaging and diagnostics using acetone-OH simultaneous PLIF (Nakamura et al, 2008).…”