Modelling of chemical vapour deposition for optical fibre manufacture

A study of numerical modelling has been carried out for chemical vapour deposition processes with applications to manufacture of optical fibres. Temperature distributions and thermophoretic particle deposition have been calculated for the modified chemical vapour deposition (MCVD) and the outside vapour deposition (OVD) processes. A two torch formulation and a heat flux boundary condition are used for MCVD and the present model is shown to be capable of predicting tube wall temperatures and deposition profiles correctly. The present results are in agreement with experimental data. For OVD modelling, nonorthogonal body-fitted coordinates have been utilized to solve a conjugate problem including the jet flow and heat conduction through a two-layered cylinder that consists of an original target and the deposited porous layers. Surface temperatures and efficiencies of particle deposition have been obtained.