Modeling of Heat Transfer in Pneumatic Conveyer Using a Combined DEM-CFD Numerical Code

摘要

A combined discrete element method (DEM) and computation fluid dynamics (CFD) numerical code was developed for modeling and simulating the flow of particles through the conveying pipe. The DEM was used to simulate the motion of the particles in the gas flow; the compressible Reynolds averaged Navier-Stokes (RANS) equations were used to describe the gas flow. During the initial heating/cooling and for small particle size, both conditions, Bi=hd_p/k_s < 0.1 and Fo = αt/d_p~2 > 0.1, are not satisfied and therefore uniform particle temperature cannot be assumed. Therefore, particle temperature distribution must be taken into account. The equation of energy conservation for a spherical particle was applied in order to predict the temperature profile of each particle. The predictions of the numerical simulations for a single particle flow in pipe were compared successfully with experimental published data. Comparisons between the uniform particle temperature, particle temperature distribution, and experimental data showed that the particle temperature distribution better agreed with the experimental data. Based on the successful validation, a parametric study was conducted.