| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber cooling apparatus and an optical fiber manufacturing method that can determine an optimum supply position for cooling gas.SOLUTION: With L minimizing the expression as L, L is close to L, where Qrepresents a downward flow rate at a periphery of an optical fiber, Qrepresents an upward flow rate at the periphery of the downward flow rate Q, and C(L) represents a volume fraction of air included in the downward flow rate Qat a distance L from an upper end of a cooling pipe part to a cooling gas feed port while a downward flow of an internal gas including air and cooling gas sucked in the an upper end is positive. Here, L represents the distance from the upper end to a supply position for cooling gas, Rrepresents a radial distance of the cooling pipe part at a border position of change in a flow direction from the downward flow rate Qto the upward flow rate Q, D represents a diffusion coefficient of the air, and length represents a diffusion distance of the air. |
