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Dissertation/Thesis Abstract

Boundary layer losses due to surface roughness in a ceramic matrix composite thruster
by Bonakdar, Mohammad, M.S., California State University, Long Beach, 2010, 48; 1486375
Abstract (Summary)

Traditional thrusters are manufactured from refractory metal which have hydraulically smooth surfaces. The aim of this research is to investigate the effect of the high surface roughness on the boundary layer losses inside thrusters that are manufactured from Ceramic Matrix Composite (CMC) materials.

This analysis is carried out on a representative radiatively cooled thruster using the Computational Fluid Dynamics (CFD) software known as STARCCM+.

A simulation is performed on a thruster with hydraulically smooth surface followed by three simulations on the thrusters with three different surface roughnesses to generate a range of data on the value of thrust as a function of equivalent sand grain roughness.

The thruster is designed to produce 490 N of thrust based on analytical calculations. In the simulation, for the hydraulically smooth surface case numerical result shows that the engine produces thrust of 461.27 N which is 93.4% of its designed thrust. This engine with a surface equivalent sand grain roughness height of 0.25 mm representing CMC material produces 452.75 N of thrust which is 91.66% of its designed thrust of 490 N.

Direct comparison of numerically acquired thrust values for smooth surface and CMC representative surface engine (461.27 N and 452.75 N respectively), shows that due to additional boundary layer losses, due to rough surface of the CMC engine, the CMC has produced 8.53 N less thrust than its smooth surface counterpart. Based on the data from this current study, the conclusion can be drawn that under the same operating condition CMC thrusters are approximately 1.8% less efficient than their smooth surface counterpart.

Indexing (document details)
Advisor: Hefazi, Hamid
School: California State University, Long Beach
School Location: United States -- California
Source: MAI 49/02M, Masters Abstracts International
Subjects: Engineering, Aerospace engineering, Mechanical engineering
Publication Number: 1486375
ISBN: 978-1-124-24765-6
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