Open Access

ARTICLE

Modeling a Discontinuous CVD Coating Process: II. Detailed Simulation Results

by Joseph G. Lawrence, John P. Dismukes, Arunan Nadarajah¹

1 Department of Chemical and Environmental Engineering, University of Toledo, Toledo, Ohio 43606, USA. Corresponding author: nadarajah@utoledo.edu

Fluid Dynamics & Materials Processing 2007, 3(3), 255-264. https://doi.org/10.3970/fdmp.2007.003.255

Abstract

The atmospheric chemical vapor deposition process on continuous glass sheets is a well developed one and the parameters that affect it are relatively well understood. When this process is converted to coat discrete glass plates it introduces a new variable, the gap between the glass plates, which can significantly impact the quality of the coatings. In this study a 2D pseudo steady state model of the process was developed to study the effect of the gap, and the ratio of outlet to inlet gas flow rates (called the bias), on the coating quality. The model was solved with the commercially available computational fluid dynamics program FIDAP which employs a finite element scheme. An earlier study had shown the validity of the pseudo steady state model and the use of FIDAP for this problem [Lawrence, J.G.; Nadarajah, A. (2006): Fluid Dynamics {\&} Materials Processing, vol.1, pp.11-17]. The simulations showed that the gas flows were always well ordered. The value of the bias and the size of the gap were found to have a significant effect on the coating rate, but had only a small effect on coating uniformity. Lower biases and gaps produced the highest coating rates and coating uniformities, but the overall coating rate will still be lower than that for the continuous glass ribbons. The results suggest that this CVD process can be adapted for discrete glass plates to produce close to uniform coatings of required thicknesses if the plate motion can be suitably adjusted.

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