A semi‐experimental model for predicting the axial transport of the granular bed in a rotating cylinder is proposed. It is based on dimensional analysis and on the determination of an apparent viscosity characterizing the flow behaviour of the bed. Unknown constants in the model are determined either by analysis or by tuning with experimental data. An example of such tuning is shown to work well. The model is capable of giving, as a function of filling angle and friction angle, the axial velocity that varies along the cylinder axis. This is important for the control of the process taking place inside the cylinder.

A three-dimensional steady-state mathematical model of a rotary calcining kiln for the petroleum coke is presented. The model takes into account all the physical phenomena of interest, from gas flow, heat transfer, volatile matter and coke dust evolution and combustion, to the granular bed motion and the thermal effects of the refractories. The model is built in modular form with several submodels coupled together. This methodology facilitates the construction of the model and its use. This article gives a detailed mathematical description of the model. A complete simulation is presented, and the results are discuss,d. Data coming from an industrial kiln in operation are used for validation, and the results show that the model can be a useful tool for solving problems of kiln operation or design.

A method for predicting the transverse motion of a granular bed in a rotary cylinder is proposed, based on a non‐Newtonian rheological model of the pseudo‐plastic type, i.e. with a flow behaviour index (n) between 0 and 1. For a good simulation of bed motion, the model must be able to adequately reproduce the bed velocity profile in both the upper (downward flowing) and the lower (upward moving) zones. It is shown that to do so there is the need to adjust not only the consistency index K but even more importantly the flow behaviour index, n. The mass and momentum conservation equations are solved by the CFD code FLUENT. The model is applied to the simulation of the motion of an alumina bed and the computed results compared with experimental data.

No abstract

No abstract