Direct-heating Skull Furnace
Development of a Mathematical Model of a Direct-heating Skull Furnace for High-melting Glass Production
Tech Area / Field
- PHY-NGD/Fluid Mechanics and Gas Dynamics/Physics
- CHE-IND/Industrial Chemistry and Chemical Process Engineering/Chemistry
3 Approved without Funding
Institute of Electronic Materials, Armenia, Yerevan
- VNIITF, Russia, Chelyabinsk reg., Snezhinsk
- IMPEX High-Tech, Germany, Rheine\nCornell University, USA, NY, Ithaca\nAuburn University / Samuel Ginn College of Engineering, USA, AL, Auburn\nUniversity of Central Florida / Center for Research and Education in Optics and Lasers (CREOL), USA, FL, Orlando
Project summaryThe topic of this project is melting in direct-heating skull furnaces in which voltage is applied to electrodes that are in the mass of melted glass which works as a heater (because melted glass performs as an electrolyte).
The furnaces ensure as high temperatures as it is necessary to produce high-melting glass. Moreover, the melt does not interact with the material of which the melt-containing vessel is made due to skulling – the formation of a protective lining between the melt and the vessel.
The Material Science Research & Production Enterprise of Armenia (Yerevan) has a skull furnace. Its water-cooled cylindrical copper body measures 70 cm in diameter and 40 cm in height. The temperature reaches 2000-2200°C in its center and 60°C at the wall. The furnace and some auxiliary systems that ensure its normal operation constitute a plant. The auxiliary systems include a power supply system, a burden-preheating unit, a burden feeder, a staking machine, (cooling) water supply system, a gas supply system to protect the discharge molybdenum pipe from erosion, and some others.
An automated system is needed to control the process so as to ensure the required quality of produced glass. To develop such a system, it is necessary to know temperatures and convection flows in the furnace as functions of several parameters including electrodes spacing, electrode voltage and founding temperature which, in turn, are dependent on the type of glass to be produced. Since it is impossible to place instrumentation inside the furnace (the temperature of the process reaches 2000°C), temperature can be measured only at peripheral points. With the mathematical model to be developed, it will become possible to improve the unique and environment-friendly method of glass production in electric skull furnaces so as to extend its capabilities and offer as glass production technology of the ХХI century.
The objective of this project is to develop a thermal model for the skull furnace. It is a rather sophisticated mathematical problem which will be solved in several steps.
The first step is to solve an adjoint problem of hydrodynamics and heat exchange, using one of the advanced licensed codes (for example, CFX), i.e., to calculate velocities and temperatures in melted glass for conduction- and convection-driven heat exchange and for different values of controlling parameters (electrode spacing, supplied current and voltage, and others).
The second step is to study the temperature field with the thermal balance method which helps
determine temperature fields for any engineering system from the solution of differential energy equations with allowance for all types of heat exchange (heat conduction, convection and thermal radiation), material thermodestruction and melting (thermal characteristics as functions of temperature), and other factors. Here the main difficulty is the adequate description of convection-driven heat exchange in melted glass. In our case, parameters of the velocity field will be determined at the first step.
The third step is to formulate the thermal model.
Based on results obtained at the two previous steps, an adequate mathematical model of the furnace will be developed. With the model developed it will be possible to predict the temperature field in the furnace, using temperatures measured by gauges installed not in the inaccessible hot core, but, for example, at peripheral points. The model will be used to control the process of glass melting in skull furnaces.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
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