Time-resolved 3D investigation of the ignition process of a methane diffusion impinging flame

Abstract

The ignition process of a methane diffusion impinging flame was investigated experimentally, using high speed schlieren/stereo imaging and image processing techniques. Two types of flame can be identified during the ignition process: premixed like flame with weak blue colour and diffusion flame with yellow-reddish colour. The 3D structure of blue flame after enhancement and yellow flame has been reconstructed and analysed seperately. The ratio between green and blue colour intensity is used to provide indications of the global fuel/air mixture state of the blue flame, which is found to correlate well with the flow conditions and flame propagation characteristics.

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…”

Experimental investigation of transient ignition dynamics of hydrogen enriched methane diffusion impinging flames

“…Huang et al [21] have established a Digital Flame Colour Discrimination (DFCD) combustion quantification scheme to identify different flame regimes based on the general spectrometric composition. The previous study [17,18] indicated that during the initial stage of the ignition process of hydrocarbon flames, there is large amount of weak blue flame, which can hardly be observed with the original high speed colour image. However, the flame structure can be fully revealed using the DFCD method.…”

“…The flame establishment under impinging conditions can be affected by multi factors, including jet flow condition, nozzle to wall distance, ignition initiation position as well as fuel compositions [13][14][15][16]. Wang et al investigated the ignition process of a diffusion propane and a methane impinging flame using high speed colour and schlieren imaging techniques [17,18], respectively. Chen et al [19] conducted a numerical study using LES on the ignition process of diffusion impinging propane flames, which reached qualitative agreement with the experimental observations reported by Wang et al [18].…”

Investigation of ignition process from visible to infrared by a high speed colour camera

“…Huang and Zhang [27,28] introduced a Digital Flame Colour Discrimination (DFCD) combustion quantification 15 scheme, which established a relation between the different flame radiation components and its colour signal presence. The intensity ratio of the B/G (in the RGB colour space) was shown to indicate the global air/fuel mixture condition [17] and equivalence ratio [29] of the blue flame region. In Fig.…”

“…Research indicated soot emission tends to obscure the CH* and C2* signals at high shutter speeds [16,17]. Directed high speed imaging from the Rolls-Royce gas-turbine combustor seems to indicate that the flame is discontinuous during the ignition process [18].…”