Investigation of the transition from single to group coal particle combustion using high-speed scanning OH-LIF and diffuse backlight-illumination

Homogeneous ignition and volatile combustion of single solid fuel particles in air and oxy-fuel conditions

“…to reconstruct the three-dimensional volatile flame topology [19,20]. Gas-phase ignition was initially observed downstream of the particle, where high temperatures and fuel-lean mixtures exist.…”

Numerical investigation and assessment of flamelet-based models for the prediction of pulverized solid fuel homogeneous ignition and combustion

“…The optical setup is schematically illustrated in Fig. 2 and was extensively described elsewhere [28]. Laser scanning utilizing an acousto-optic deflector (AOD) has been demonstrated in turbulent gaseous flames [63] and was im- A DBI system consisting of a CMOS camera and a high-power LED was operated at 10 kHz to measure the in-situ particle number density (PND) and particle velocity profiles simultaneously.…”

“…The statistical evaluation was conditioned both on the PND and the axial-positions of the particle jet. For more details about the experimental methodology and data processing steps, the reader is referred to [28].…”

“…Therefore, the accurate prediction of the transition from single to group particle combustion must be an essential feature of PCC models. To provide the necessary validation basis, the two experimental setups mentioned above were recently extended to investigate particle group combustion [27,28]. Both studies report a significant increase in ignition delay time at higher particle loads.…”

“…Both studies report a significant increase in ignition delay time at higher particle loads. Furthermore, Li et al [28] found a transition from spherical flames around single particles to a conical flame around particle groups. This transition has been reproduced by Nicolai et al [11] in a simulation using a competing two-step model coupled with an FGM approach.…”