Abstract
There have been innumerable contributions to clarify bubble behaviour in glass melt, where various approaches have been carried out. Experimental results show bubble quality is represented by bubble number density, bubble diameter, and standard deviation of the diameter, which depend on time and temperature. The latest experiment implies growth of bubble is strongly dependent on temperature, and the standard deviation is independent of time and temperature. Not only appeared location but also number density of small bubble (seeds) is of major concern for manufacturers to produce high quality glass. A new mathematical model is developed to predict bubble number density, which quantifies effect of both fining and refining on the density by introducing an exhausting effect of bubbles from upstream of the highest temperature area, i.e. hot spot, and the downstream in melter, i.e. stagnant. Inlet bubble number density with melting down is extrapolated from the published data. Monitored diameter obtained in experiment is applied to calculation. Calculated bubble number density is compared with measured one in an actual flat glass furnace, which makes it clear that the mathematical model is valid to predict order of the density in the glass melt. Numerical simulation gives reasonable suggestion about fining effect.
