| With a whole consideration of three mathematical models, namely glass flow movement and heat transfer model, which have been established particularly for float glass tank by predecessors, the chemical concentration diffusion model and air bubble fining model are built in thesis. The method of SIMPLEC was applied to calculate the distribution of temperature and velocity field, and subsequently the gas concentration distribution in glass liquor is calculated and the process of bubble fining is calculated under different working conditions.Studying on the distribution of the gas concentration field and the simulation of the bubble fining process, it can be concluded that: gas concentration is a little high in the former of the glass tank, while it is somewhat low in the fining and cooling area of the glass tank; after fining for a time, the air bubbles on the hotspot is smaller, while it is a little big in the fining and cooling area. The fining process of air bubble is influence greatly by the circulations of the glass velocity field.From the research on the different processing systems, the following conclusions can be drawn. Compared with the "Mount" temperature system, the "double hotspot" and the "bridge" temperature system have high temperature and its bubble fining is best. The study on the variation of the gas pressure in the tank shows that: when the pressure reduces from normal degree to ISKpa, the gas concentration has only a little low. When the pressure is at 25KPa, the glass fining is perfect. It is shown by the study on the variation of surface tension that the viscosity of glass decrease when the surface tension went down, which is of help to fine the air bubble. In the front fining area of the tank, the surface tension was relatively high (about 0.38N/m2 ), the glass liquor fines much better than it could do when the surface tension is low, but in the back part of the cooling area, the glass liquor with low surface tension could also fines well. The study on the change of the output capacity shows that it has great influence on the fining exponential, namely good or bad fining conditions. When the output is less, thetemperature in the tank, goes up, the viscosity reduces, accordingly, the time in which bubble comes out of the liquor is shortened. Furthermore when the output is less, the velocity of glass liquor was low and the fining time was relatively long, thus the glass fining exponential is high, correspondingly, the glass fining condition is improved. When the output verified from more to less, the gas concentration in glass is obviously low, and the amount of the fining bubble is increased. |
