Measurement of two-dimensional concentration fields of a glycol-based tracer aerosol using laser light sheet illumination and microcomputer video image acquisition and processing

The use of a tracer aerosol with a bulk density close to that of air is a convenient way to study the dispersal of pollutants in ambient room air flow. Conventional point measurement techniques do not permit the rapid and accurate determination of the concentration fields produced by the injection of such a tracer into a volume of air. An instantaneous two dimensional distribution would aid in the characterization of flow and diffusion processes in the volume studied, and permit verification of theoretical models. A method is developed to measure such two dimensional concentration fields using a laser light sheet to illuminate the plane of interest, which is captured and processed using current microcomputer-based video image acquisition and analysis technology. Point concentrations, determined optically using extinction of monochromatic illumination projected through the aerosol onto a photo detector, are used to calibrate the captured video linages to detennine actual concentration values. Accuracy, reproducibility, and maximum rate of data acquisition are evaluated by means of theoretical models of ambient air flow in a sealed box with pointinjection of the tracer, and in a duct of circular cross section with constant air velocity under both constant and pulsed injection scenarios.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Architecture.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1992

Author dc:creator

• Revi, Frank

Advisor dc:contributor.advisor

• James W. Axley.

• Architecture.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/69291

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/69291