Home // ICQNM 2012 , The Sixth International Conference on Quantum, Nano and Micro Technologies // View article

Evanescent Wave-based Near-wall Thermometry Utilizing Brownian Motion

Authors:
Reza Sadr
Anoop Kanjirakat

Keywords: Total Internal Reflection; nPIT; thermometry.

Abstract:
Evanescent wave-based Particle Image Velocimetry (or nPIV) is known to be an effective tool in estimating near-wall velocity fields. nPIV uses evanescent wave illumination of particle tracers in the fluid within order of O(100nm) from the wall where illumination intensity decays exponentially with distance normal to the wall. Brownian motion of the sub-micron tracer particles used in nPIV is a function of fluid temperature in this region. Monte Carlo simulation of particle movement in this region is used to investigate the possibilities of utilizing this effect for near-wall thermometry. Synthetic nPIV images of the illuminated polystyrene particles of 100nm diameter in the near-wall region are initially generated for different fluid temperature measurement. The spatial distribution of the particles takes into account the forces such as buoyancy, electrostatic repulsion and van der Waals attraction, in addition to the hindered Brownian motion near the walls. The synthetic images were then processed using standard cross-correlation function. The results of the numerical simulation show that the temperature variation causes a change in width and height of the nPIV correlation function. Initial experimental studies are conducted to verify the results of simulations.

Pages: 12 to 17

Copyright: Copyright (c) IARIA, 2012

Publication date: August 19, 2012

Published in: conference

ISSN: 2308-3530

ISBN: 978-1-61208-214-1

Location: Rome, Italy

Dates: from August 19, 2012 to August 24, 2012