Modeling of Pulverized Coal Combustion in Cement Rotary Kiln
In this paper, based on analysis of the chemical and physical processes of clinker formation, a heat flux function was introduced to take account of the thermal effect of clinker formation. Combining the models of gas-solid flow, heat and mass transfer, and pulverized coal combustion, a set of mathematical models for a full-scale cement rotary kiln were established. In terms of commercial CFD code (FLUENT), the distributions of gas velocity, gas temperature, and gas components in a cement rotary kiln were obtained by numerical simulation of a 3000 t/d rotary kiln with a four-channel burner. The predicted results indicated that the improved model accounts for the thermal enthalpy of the clinker formation process and can give more insight (such as fluid flow, temperature, etc,) from within the cement rotary kiln, which is a benefit to better understanding of combustion behavior and an improvement of burner and rotary kiln technology.
CFD Modeling of Meat and Bone Meal Combustion in a Rotary Cement Kiln
 Abstract—This paper presents a three-dimensional computational fluid dynamics (CFD) modeling study carried out for a rotary cement kiln withal multi-channel burner with swirl and high momentum air components. The simulations are performed using the commercial CFD software ANSYS FLUENT, version 13.0, and are carried out for coal as well as for meat and bone meal (MBM) combustion using the eddy-dissipation model for combustion. Steady-state solutions are obtained using the Lagrangian approach for the particle phase and the Eurasian approach for the continuous phase. The turbulence is modeled by the RNG k-e model, and gas-phase radiation is modeled by the P1 radiation model. The effect of MBM fuel properties on combustion characteristics such as temperature, fuel devolatilization, volatiles and char burning, in comparison with coal, are presented and discussed. It was found that MBM combustion products temperatureis300K lower than that of coal, and the char burnout of MBM is 83%. This poor burnout is mainly due to bigger MBM particles.
The history and development of the dental surveyor--Part III.
The dental surveyor is an indispensable instrument capable of performing a number of prosthodontic procedures. Surprisingly, the technique of surveying casts as part of the treatment planning procedure did not emerge until early in the twentieth century. This article reviews the origins and early use of the dental surveyor. It includes features common to all surveyors as well as the principal uses of these instruments.