Numerical and experimental investigation of particle transport by convection, diffusion and thermophoresis

Author

Arun Janakiraman

Abstract

"Thermophoretic and diffusional losses that occur inside an aerosol sampling probe which is used for sampling jet exhaust gases are studied and a numerical model to predict the losses under different operating conditions is developed. The sampling probe is the hardware that is inserted near the exit plane of the gas turbine engine to collect the particle laden jet exhaust sample. The probe is interfaced directly with the transfer (sampling) lines. The probe must be designed to survive severe thermal environment, while providing a valid sample of particle laden exhaust to the analyzers. One of the major issues related to probe design is the transport losses that occur inside the probe during collection and transportation of the aerosol particles. A study of how the particles behave inside the probe can be very useful to quantify the effectiveness of the probe. The major factors which contribute to particle losses inside the probe are diffusion and thermophoresis. Only monodisperse particles are considered as the goal is to quantify the losses and not the particle size evolution. The particulate losses occurring inside the probe are quantified by means of a parameter called the penetration, the fraction of particles that survive. In order to validate the model, the results from the model are compared with results from previous experimental and theoretical investigations. A simple experiment was performed to further validate the study of thermophoretic and diffusional losses. It is found that thermophoretic deposition depends significantly upon the temperature difference between the gas and the wall and the thermophoretic coefficient (K_th) for this particular kind of flows. The penetrations for various operating conditions of the probe are given as a function of wall temperature. It is found that the penetration drops as the difference between the wall and gas temperatures increases"--Abstract, page iii.

Advisor(s)

Kakkattukuzhy M. Isaac

Committee Member(s)

Philip D. Whitefield
Kelly Homan

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering

Publisher

University of Missouri--Rolla

Publication Date

Spring 2006

Pagination

xi, 54 pages

Note about bibliography

Includes bibliographical references (pages 52-53)

Rights

© 2006 Arun Janakiraman, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

Fluid dynamics -- Mathematical modelsNanoparticlesTransport theory -- Mathematical models

Thesis Number

T 8959

Print OCLC #

85254679

Recommended Citation

Janakiraman, Arun, "Numerical and experimental investigation of particle transport by convection, diffusion and thermophoresis" (2006). Masters Theses. 3870.
https://scholarsmine.mst.edu/masters_theses/3870