Won Yang

Mathematical model of thermal processes in an iron ore sintering bed

An unsteady one-dimensional model of an iron ore sintering bed with multiple solid phases was proposed. The proposed model confers a phase on each solid material. The present model was established with a series of conservation equations in the form of a partial differential equation for each solid phase and gas phase. Coke combustion, limestone decomposition, gaseous reaction, heat transfers in/between each phase, and geometric changes of the solid particles are reflected by each term of the governing equations. Simulation results are compared with the limited experimental data set of sintering pot tests. Parametric studies for various initial water contents and coke diameters have also been performed. The simulation results predict the experimental results well and show physically reasonable trends for various parameters.

Unsteady one-dimensional model for a bed combustion of solid fuels

Abstract A transient one-dimensional combustion model of a solid fuel bed that can be applied to various types of combustors employing the solid bed is suggested. Configuration of solid beds can be characterized by combinations of solid and gas flow directions, ignition methods, and dominant reactions. These features can be reflected numerically to the boundary and initial conditions of the model, while the governing mechanism in each type of bed is similar. The mechanism is expressed as forms of conservation equations for the solid and the gas phase. Solid-gas reactions, gaseous reactions, heat transfer, geometrical changes of the particles, and physical properties are modelled and reflected to each term of the governing equations. Simulation results are shown for two cases: a packed bed combustor and an iron ore sintering bed. Two cases have distinctively different bed configurations and ignition methods. The propagation rates of the combustion zone are quantitatively discussed in terms of the flame propagation speed. Future development of the model is discussed for possible application to more complicated simulation cases.

Application of Intra-Particle Combustion Model for Iron Ore Sintering Bed

In order to quantitatively predict the behavior of the material in the packed bed, a single particle model is developed to describe the combustion and sintering process inside an individual particle composed of multiple solid material fines, including iron ore, coke and limestone, and is applied to the combustion modeling of an iron ore sintering. By analyzing three typical fuel distribution cases using the developed single particle combustion model, the effects of temperature and oxygen concentration gradient inside the particle on heat and mass transfer and the combustion behavior of the iron ore sintering process are investigated. Considering the various combustion rates which are highly dependent on the fuel distribution methods, correction factor for single particle model is also introduced and systematically analyzed. The aim of this research is to supplement particle technology to conventional approach and it is found that the oxygen concentration gradient inside the particle is significantly affected from the mixing method thereby changing the completion times of sintering process.

A process simulation model for a 2 ton H-1 incinerator (a combined bed combustion and furnace heat transfer model)

A process simulation model was constructed for a 2 ton h - incinerator. The simulation model was designed to provide system performance parameters according to various operating conditions. In accommodating the wide variation of quality and composition of input wastes, the plant operating parameters such as amount of excess air, preheated air temperature, waste feed rate and primary air distribution over the stoker, etc. must be carefully controlled. The proposed model calculates operating variables of each submodule, by employing steady-state thermal and material balance equations. Combustion of waste bed, and its radiative heat transfer in the combusion chamber are considered. The calculated results of the combustion chamber performance are evaluated, in terms of temperature, locations and width of the flame band, and mean residence time in the secondary combustion chamber. These results are compared with a limited set of field test measurements for verification of the model.

LAMF: Lighting Adjustment for Mood by Food: RFID Based Context Aware Food Ordering and Lighting Control System at Restaurants

A Ubiquitous environment is expected to provide appropriate services based on the identified context regardless of time and place. For satisfying this demand, activated communication among participating objects is essential. RFID is in the spotlight as communication means due to its economic feasibility and expandability and has been attempted to be applied to various domains. The system proposed in this research is a part of smart restaurant system that automatizes food order, bill payment and mood associated lighting control depending on the served food types supported mainly by the RFID technology. This efficient and innovative system could not only reduce time and cost for managing a restaurant but also provides synthesized real-time mood lighting for the customers to enhance their emotion rich dining experiences.

Analysis of the Thermal Processes in the Iron-Making Facility - Modeling Approach

Thermo-fluid characteristics in coke oven, sintering machine and blast furnace in iron-making facility are key processes related to the quality and productivity of the pig iron. Solid material in the processes usually forms a bed in a gas flow. For simulation of the processes by mathematical model, the solid beds are idealized to be a continuum and a reacting solid flow in the gas flow. Governing equations in the form of partial differential equations for the solid material can be constructed based on this assumption. Iron ore sintering bed is simulated and limited amount of parametric study have been performed. The results have a good agreement with the experimental results or physical phenomena, which shows the validity and applicability of the model.