Multiphase Radiation Characteristics of a Laboratory-Scale Pulverized Coal Flame

A coal combustion solver with detailed multiphase radiation modeling has been developed and applied during the simulation of a laboratory-scale coal flame in this work. The carrier gas is modeled by the Eulerian equation while the coal particles are tracked in a Lagrangian framework. Radiative heat sources are fed back to the energy equations of both carrier gases and dispersed particles. The spectral properties for both gases and coal particles are either calculated by the full-spectrum k-distribution (FSK) method or considered to be gray, and the radiative transfer equation is solved by the spherical harmonics (PN) method at different orders. High-fidelity radiation effects on temperature, liftoff height, combustion products, and coal burnout for the target flame are investigated. It is found that radiation has a significant cooling effect on the flame. Involving radiation during the simulation of target flame makes both liftoff height and coal burnout closer to the experimental measurements, and also alters the combustion productions. Results also show that, considering both accuracy and efficiency, the P1 solver combined with either FSK method or gray method should be acceptable an alternative for multiphase radiation modeling of target flame.