| Popis: |
The present paper carried out an entropy generation analysis of radiativeheat transfer process in three-dimensional coal-fired furnaces. The gasesincluding CO2 and H2O and particles including soot, flyash and char were considered as participated medium. Radiative transferequation in the non-grey medium was solved by discrete ordinate method (DOM),in which radiative properties of gases, soot, fly ash and char were obtained bystatistical narrow-band correlated-k model (SNBCK), Rayleigh’s theory and Mietheory, respectively. The distribution of local volumetric radiative entropygeneration rate as well as local wall radiative entropy generation rate werecalculated and analyzed. The contributions of various medium in coal-burnedfurnaces on radiative entropy generation were evaluated, and the influences ofpertinent parameters, such as fuel atmosphere, burnout rate and diameter ofpulverized coal as well as volume fraction of particles on radiative entropygeneration rate and dimensionless entropy generation were investigated.Numerical results shown that the irreversibility of the particle radiationprocess results in more than 80% of the volumetric radiation entropygeneration, and can’t be neglected in coal-burned furnaces. |
