Award Date

5-2004

Degree Type

Thesis

Degree Name

Master of Science in Mechanical Engineering (MSME)

Department

Mechanical Engineering

First Committee Member

Mohamed B Trabia, Chair

Second Committee Member

William Culbreth

Third Committee Member

Ajit K. Roy

Fourth Committee Member

Robert A. Schill

Number of Pages

176

Abstract

Niobium cavities are important component of the linear accelerators. Researchers have concluded that buffered chemical polishing on the inner surface of the cavity improves its performance. However the mechanism of chemical polishing is not well understood. A finite element computational fluid dynamics (CFD) model was developed to simulate the fluid flow characteristics of chemical etching process inside the cavity. The CFD model is then used to optimize the baffle design. The analysis confirmed the observation of other researchers that the iris section of the cavity received more etching than the equator regions. The baffle, which directs flow towards the walls of the cavity, was redesigned using optimization techniques. The redesigned baffle significantly improves the performance of the etching process. To verify these results an experimental setup for flow visualization was created. The setup consists of a high speed, high resolution CCD camera. The camera is positioned by a computer controlled traversing mechanism. A dye injecting arrangement is used for tracking the fluid path. The Experimental results are, in general, in agreement with the CFD and the optimization data.

Keywords

Etching; Harry Reid Center; Holes; Linear accelerators; Niobium – Surfaces; Surfaces (Technology)

Disciplines

Dynamics and Dynamical Systems | Materials Science and Engineering | Mechanics of Materials | Nuclear Engineering

Language

English

Comments

Incomplete paper data