Motoichi Iga

An integrated mathematical model of float process

Abstract An integrated mathematical model of the float process has been developed. This integrated model consists of a glass ribbon forming model, a float bath heat transfer model and a molten tin flow model. In the float process, glass ribbon forming and heat transfer in the bath influence each other. That is, the viscosity of the glass ribbon depends strongly on its temperature. Also, molten tin flow, which plays an important role in the bath heat transfer, is caused by glass ribbon traction and buoyancy convection. Therefore these three models are linked with one another. In the first model, the molten glass flow on the molten tin is simulated as viscous fluid flow. In the second model, three-dimensional radiative heat transfer is simulated. In the third model, three-dimensional turbulent flow of the molten tin is simulated. It is found that the simulated results are in good agreement with the measurements in the actual process. This integrated model can be used to study the mechanism in the float process, and moreover to optimize the operating conditions and to design float baths.

Single-sided linear induction motor controlling the surface shape of molten tin

Abstruct-This paper presents theoretical analyses and experimental results of molten-tin control using a 1.5meter-wide Single-sided Linear Induction Motor (SLIM) to improve the float process of forming sheet glass. Fist, a mathematical model of molten tin controlled by a SLIM is derived. It is shown that theoretical predictions agree with experimental results within 5% error. Second, vibration of molten tin surface is discussed from experimental results. The molten tin surface is vibratory under the condition that the initial height of molten tin is greater than 0.6 dimensionless height (the raho of height to the specific wave length of SLIM). Finally, two locations of SLIM are compared from the stand point of application for the actual float process. It is theoretically demonstrated that the lower location to molten tin is superior to the upper location.

Single-sided linear induction motor controlling the surface shape of molten tin (glass formation)

Presents theoretical analyses and experimental results on molten-tin control using a 1.5-m-wide single-sided linear induction motor (SLIM) to improve the float process of forming sheet glass. First, a mathematical model of molten tin controlled by a SLIM is derived. It is shown that theoretical predictions agree with experimental results within 5% error. Second, the vibration of the molten tin surface is vibratory under the condition that the initial height of the molten tin is greater than 0.6 dimensionless height (the ratio of height to the specific wavelength of SLIM). Two locations of SLIM are compared from the standpoint of application to the actual float process. It is theoretically demonstrated that the lower location to molten tin is superior to the upper location. >

NUMERICAL SIMULATION OF FLOAT GLASS FORMING PROCESS

A pseudo three-dimensional model of glass ribbon in the float glass forming process has been developed. In the manufacture of thin float glass the glass ribbon is stretched not only in the longitudinal direction, but also in the lateral direction by the use of edge rollers, because the equilibrium thickness of glass ribbon is about 7 mm. The operation of edge rollers affects the quality of float glass, however, time is required to optimize the setting of edge rollers empirically. In this study, a mathematical model of molten glass flow on molten tin is constructed by means of the Shallow Water formulations. Then, a finite element formulation of this model is developed and applied to the forming of 4.0mm float glass. The computed results are compared with recorded measurements of the manufacturing process, and empirical and simulation data were found to be in agreement.