Graduation Semester and Year

2016

Language

English

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Albert Y Tong

Abstract

Spin coating is a surface coating process which involves spreading a liquid dispensed on the center of a rotating substrate. The liquid is discharged using a suitable method on to the substrate rotating at a constant angular speed. The spinning speed is controlled to obtain a coating of desired thickness with faster spinning resulting in thinner coating. The thickness of the coating also depends on the properties of the fluid and other process parameters. Centrifugal force is introduced into the code as radial component of acceleration. The first part of the code solves the continuity and the Navier-Stokes equations, with which the pressure and velocities are obtained. Solution to the Navier-Stokes is obtained using the two-step projection method. An intermediate velocity is generated in the first step which is used in the second step when a pressure poison equation (PPE) is solved with the value of the intermediate velocity obtained from the first step. In the second part of the code, free surface tracking is done using a Coupled Level Set Volume of Fluid (CLSVOF) method. In CLSVOF method, the combined advantage of Volume of Fluid (VOF) and Level Set (LS) results in efficient mass conservation and accurate free surface reconstruction. Solidification is done using an enthalpy-porosity technique with a source term accounting for phase change. In this study, thin film formation under the action of spinning is investigated. A parametric study is carried out. The effects of angular velocity, ramp rate, substrate temperature, initial droplet temperature and latent heat on the thickness of coating are studied. The results obtained are in accordance with experimental data reported in the literature.

Keywords

Spin coating, Numerical studies, Metals

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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