Engineering

Materials science

Mineralogy

Operating system

Particle size

Computer science

Cloud computing

Forced convection

Chemical engineering

Geology

Coal

Oceanography

Physical chemistry

Waste management

Thermodynamics

Physics

Organic chemistry

Particulates

Soot

Combustion

Environmental science

Particle (ecology)

Chemistry

Meteorology

Mechanics

Convection

International journal of greenhouse gas control

Soot cloud size is important in radiative heat transfer and particulate matter emission since it determines the integral effect in the sooty region; meanwhile, study on soot cloud size during single coal particle combustion is essential to develop theories of soot-relevant reaction pathways and mass transport. In this work, a 1-D transient coal combustion model with an empirical soot model was adopted and validated to study the effect of gas physicochemical properties and forced convection on soot cloud size (ls/r0). Tar gasification results in a larger ls/r0 at any xO2, while soot gasification has a limited effect at low xO2 and leads to a larger soot cloud size at high xO2. The effect of tar and soot diffusion becomes more important at higher oxygen mole fraction; a larger heat capacity leads to a larger soot cloud size. In O2/N2 environments, soot cloud size increases when Rep increases from 0 to 10 and decreases when Rep increases from 10 to 16. In O2/CO2 environments, soot cloud size increases dramatically when Rep increases from 0 to 13 and slightly decreases when Rep increases from 13 to 16. The ls/r0 in O2/CO2 is always larger than that in O2/N2. The effect of convection on soot cloud size has two sides. On one hand, the blow away effect tends to increase the ls/r0. On the other hand, convection may increase or decrease total soot mass, leading to an increase or decrease of ls/r0, respectively.

Soot cloud size of a single coal particle in air/oxy combustion under forced convection