Numerical study on inlet operational conditions in the outside vapor deposition process

Operational conditions at inlets of outside vapor deposition (OVD) play an important role in production yields and quality of optical fiber preforms. This work aims to numerically investigate the inner states and SiO2 deposition performance of OVD under different inlet operational conditions. This is based on a recently devel-oped Eulerian-Eulerian multiphase OVD process model which is extended to consider the SiO2 particle nucleation and growth. The effects of inlet operational conditions are investigated in terms of the flow rate of SiCl4/O-2-H-2- O-2, the mass fraction ratio of SiCl4/O2 as well as different carrier gases (H2, N2 or O2). The simulations show that there exists an optimal SiCl4/O2 flow rate to yield the maximum deposition efficiency. While the deposition efficiency decreases with increasing either O2 or H2 flow rate. The reduction of the mass fraction ratio of SiCl4/O-2 leads to a dramatic decline in deposition efficiency, whereas the averaged particle diameter of SiO2 on the target is insensitive to the variations of the SiCl4/O-2 mass fraction ratio. In addition, using H-2 or N-2 as carrier gas instead of O2 leads to a nonuniform SiO2 distribution and a significant decline in SiO(2 )particle sizes on the target.The results reveal that selecting inlet operational conditions is an effective tool to adjust deposition efficiency and control the quality of SiO2 particles on the target.

Automated summary

The study numerically investigates the impact of different operational conditions at the inlets of OVD on SiO2 deposition efficiency and quality. Results show that adjusting the flow rate of SiCl4/O2 and the type of carrier gas can effectively alter the deposition efficiency and quality of SiO2 particles.