Some features of the convective movement of molten glass at the hot spot of a flat glass furnace

1981 ◽  
Vol 38 (4) ◽  
pp. 163-166
Author(s):  
E. P. Markov ◽  
N. A. Pankova

2008 ◽  
Vol 39-40 ◽  
pp. 607-612
Author(s):  
Bernhard Fleischmann

A part of a soldier block, placed in a float glass furnace near the hot spot area, was investigated to learn about the changes in the microstructure during the production of the block, during the use for glass melting and after the shut down of the furnace and the cooling of the block. Beside the three phases after the production (baddeleyite, corundum, vitreous phase) during use as a soldier block mullite and secondary corundum as well as secondary zirconia may occure. Cooling down the used block after the furnace campaign the beginning of the crystallisation of feldspars may be seen.



My subject is the float process for making flat glass. I would like, first of all, to put the float process into perspective by describing briefly, and in simple terms, the methods used for making flat glass before and at the time of the invention of the float process and then to describe the development of the process itself and the position it occupies in the flat glass industry today. Finally, I would like to describe in as much depth as time allows, three of the main problems which had to be tackled in developing this process. The Egyptians seem to have been the first people to realize what could be done with glass when it is hot and plastic, and they made vessels for cosmetics and perfumes by, it is assumed, trailing molten glass around a shaped core. By Roman times glass was being blown and moulded, cut and engraved, painted and gilded, and the Romans had mastered the plastic character of heat softened glass so fundamental to today’s processes.



1978 ◽  
Vol 35 (3) ◽  
pp. 128-130
Author(s):  
V. E. Kopelev
Keyword(s):  


1981 ◽  
Vol 9 ◽  
Author(s):  
H. D. Smith ◽  
D. M. Mattox ◽  
W. R. Wilcox ◽  
R. S. Subramanian ◽  
M. Meyyappan

ABSTRACTTheory and ground based studies of bubble behavior in a fluid in the presence of a temperature gradient strongly indicate the action of a thermocapillary force which causes the bubbles to move. This'phenomenon been considered in the traditional treatments of glass fining. To demonstrate that the observed motion conformed to theoretical prediction it was necessary to perform the experiment under low gravity conditions. NASA's SPAR program provided an excellent opportunity to do this.A sodium borate melt containing a specific bubble array was subjected to a well defined temperature gradient for more than 4 minutes. The sample was contained in a platinum/ fused-silica cell which permitted photographic coverage of the experiment. Photographs were taken at one second intervals during the course of the experiment. They clearly show that the bubbles move toward the hot spot on the platinum heater strip. The observed motion is consistent with the theoretical predictions for the temperature gradients parallel and perpendicular to the heater strip.



2000 ◽  
Author(s):  
Christopher Q. Jian

Abstract In the fiberglass production process, glass is produced from various batch ingredients in a glass furnace. The molten glass is then delivered, through a delivery system that is often called the front-end system, to the various downstream forming operations. Multiple complex processes take place in the glass furnace, which include the turbulent reacting flow in the combustion space; laminar flow dominated by natural convection in the molten glass; fusion of raw batch materials to form molten glass; radiation and convective heat transfer between the combustion space and the molten glass; bubbling flows in the glass; and Joule heating within the molten glass, etc. The main task of the glass furnace is to convert raw batch materials into glass and thermally and chemically condition the glass before being delivered to the front-end system. One of the major tasks of a front-end system is to insure that the glass is conditioned to the specifications required by the forming operations while maintaining the highest glass quality. Improperly designed and/or operated furnace and front end delivery system can cause a number of problems to the forming operations, ranging from poor glass quality with defects to shortened furnace service life. CFD has become an increasingly important tool for glass manufacturers to guide and optimize such system designs and operations. The current work is part of an effort to leverage CFD resources in the decision-making processes in engineering, operations, and businesses. The furnace modeling was performed using the recently implemented batch melting model jointly developed by Owens Corning and Fluent, Inc., which features three-dimensional simulation of an entire glass furnace including combustion, bubbling, and electrical boosting. The thermal coupling procedure between the combustion space, batch, and the melting tank along with the associated convergence issues are discussed. The modeling results are presented along with comparison with field measurements.



2000 ◽  
Vol 150 (1-6) ◽  
pp. 77-97 ◽  
Author(s):  
M.Q. McQUAY ◽  
B.W. WEBB ◽  
A.M. HUBER


2015 ◽  
Vol 57 (2) ◽  
pp. 175-188 ◽  
Author(s):  
NEVILLE D. FOWKES ◽  
ANDREW P. BASSOM

In a glass furnace solid batches of material are fed into a chamber and radiation heating applied. An individual batch is melted over the course of several minutes to form molten glass. A travelling front within the batch designates the progress of the melting, a process characterized by multiple radiation reflections. This results in an effective conductivity within the melting zone that is significantly larger than that in the unmelted batch. Approximations based on these disparate conductivities enable accurate explicit expressions for the almost constant melting front speed and the associated temperature profile to be derived. Our results compare favourably with existing numerical simulations of the process, with the advantage of being both analytic and relatively simple. These predictions may be useful in suggesting how a furnace might be most effectively controlled under varying batch conditions, as well as ensuring the quality of the glass sheets produced.



1992 ◽  
Vol 49 (1) ◽  
pp. 13-16
Author(s):  
I. M. Savina ◽  
V. P. Bespalov ◽  
L. Ya. Levitin ◽  
O. N. Popov


1976 ◽  
Vol 33 (7) ◽  
pp. 413-416 ◽  
Author(s):  
G. V. Pavlovskii ◽  
M. D. Voronin ◽  
V. V. Filippov ◽  
V. S. Pavlov ◽  
N. A. Khovanskaya ◽  
...  
Keyword(s):  


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