THREE-DIMENSIONAL NUMERICAL MODELING OF GLASS MELTING PROCESS
Abstract
This study develops methodology capable of simulating numerically a glass melting furnace. To this end, the major elements of the glass melting process (batch melting, melt circulation, and electric boosting) were modeled using a simplified combustion space heat transfer analysis. Due to the three dimensionality of the glass melting tank and the presence of the free surface, the circulation and heat transfer within a glass melt was simulated using conservation equations in terms of primitive variables. Radiative transfer within the melt was approximated as a diffusion process. The predictions were verified by comparing the results with experimental data from a scaled physical model. Batch (raw materials) melting was simulated considering chemical reactions and gas percolation through the granular layer. Melting from the top was treated by considered conduction and advection of heat in the melt layer, and convection and radiation from the combustion space above. The radiative flux was calculated from a spectral two-flux approximation. Melting from the solid batch bottom was determined from knowledge of heat transfer from the glassmelt below. Streamline coordinates were employed in order to accommodate the irregular physical domain. Inclusion of reaction kinetics was found to be important for realistically predicting the melting rates. Electric boosting to improve circulation patterns and the heat transfer from the melt to the batch was modeled. Due to the small characteristic Hartmann number, the ponderomotive forces in the momentum equations were neglected. The voltage and electrical current fields within the melt were determined by solving the real and imaginary parts of the electric potential. The Joulean heating was determined and coupled to the energy equation of the melt. The relevant processes were integrated into system model capable of simulating batch melting, glass circulation and heat transfer, and electric boosting in a glass melting furnace. Numerical simulations were performed to gain improved understanding of the processes which is important for design and efficient operation of the system.
Degree
Ph.D.
Subject Area
Mechanical engineering
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