HEAT TRANSFER ANALYSIS ON THE PREFORM HEATING AND THE GLASS FIBER DRAWING IN A GRAPHITE FURNACE FOR OPTICAL FIBER MANUFACTURING PROCESS

광섬유 생산공정용 퍼니스 내의 모재 가열 및 유리섬유 인출에 대한 열전달 해석

Glass fiber drawing from a silica preform is one of the most important processes in optical fiber manufacturing. High purify silica preform of cylindrical shape is fed into the graphite furnace, and then a very thin glass fiber of 125 micron diameter is drawn from the softened and heated preform. A computational analysis is performed to investigate the heat transfer characteristics of preform heating and the glass fiber drawing in the furnace. In addition to the dominant radiative heating of preform by the heating element in the furnace, present analysis also includes the convective heat transport by the gas flowing around the preform that experiences neck-dawn profile and the freshly drawn glass fiber at high fiber drawing speed. The computational results present the effects of gas flow on the temperature of preform and glass fiber as well as the neck-down profile of preform.