Evaluation of heat transfer on a backward acting grate

Abstract

Within this contribution the effect of the kinetics of bar motion on the heat-up characteristics of a packed bed, consisting of biomass or municipal waste, on a back-ward acting grate is investigated. Transfer of heat within a packed bed of moving particles determines to a large ex-tent the individual temperatures of particles, and therefore, any reaction process attached to the particles e.g. packed bed. Thus, a deeper knowledge of heat transfer in a packed bed allows for a better assessment of the reaction progress. Both motion and heat-up of particles on a backward acting grate are predicted by the Discrete Particle Method (DPM). Contrary to continuum mechanic approaches, a packed bed consists of a finite number of individual particles. Motion of particles is predicted by the Discrete Element Method (DEM), whereas the particles' temperatures are determined by the solution of the conservation equation for energy. Particles are heated by a radiative flux on the surface of the packed bed and exchange heat by conduction and radiation with particles in their proximity. Additional heat transfer to the surround-ing gas phase by convection is also taken into account.

DOI: http://dx.doi.org/10.5755/j01.mech.20.1.3775