Numerical evaluation of fuel atomization in a coal-fueled engine

A cycle simulation for a coal-fueled, internal combustion engine was modified and used to investigate the role of fuel atomization on the ignition and combustion processes. Four different atomization models were considered for this work. These included: (1) separate droplets and particles being formed; (2) concentric single or agglomerate particles in each droplet; (3) multiple particles in each droplet without agglomeration; and (4) initial multiple particles in a droplet with subsequent secondary atomization. For this work the secondary atomization was assumed to occur at the point where 50 percent of the liquid by volume was vaporized. The numerical simulation includes models for solid coal particle combustion, coal devolatilization, liquid evaporation, air entrainment, and cylinder heat transfer. Overall, atomization was identified as an important process which could significantly impact both the ignition and combustion processes.