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Feasibility of a new generation of test apparatus for airborne particulate systems

Objective

The aim of this project is to reduce the dimensions of aerosol test specimens and systems by up to one-fifth of full scale. The validity of the results will be established by comparing full-scale and small-scale aspiration-efficiency measurements on a selection of typical dust monitoring inlets.
The scaling methodology was developed and verified by means of computational fluid dynamics. Scaled test systems for both calm air and for moving air scenarios were constructed. Test inlets were manufactured to provide examples of typical applications for the scaled test systems. Experiments were carried out on different scales, and for different external conditions (i.e. wind speed, orientation). The results were analysed to deduce the range of conditions for which scale-invariance was obtained. Scale invariance was demonstrated for one type of inlet. Experimental error was approximately the same for full-scale and small-scale tests, however the small scale tests took much less time to perform (a time saving of 1-2 orders of magnitude).
Background:
At present, large-scale complex facilities such as wind tunnels and test cabins are needed to develop and test aerosol samplers such as personal samplers on manikins. Full-scale tests are time-consuming and can only be carried out in the small number of institutes that have suitable facilities. It is theoretically possible to dimensionally scale these experiments, while at the same time retaining dynamic similarity, and thus obtain the same results on different scales. To date however scaled aerosol test systems have not been implemented and validated. The motivation for this project is the very significant cost savings that could result from a successful implementation of scaled aerosol testing. Tests carried out on a reduced scale will employ much faster measurement techniques, be less costly and therefore accessible to a wider range of potential users.

Objectives: The aim of this project is to reduce the dimensions of aerosol test specimens and systems to as low as one-fifth of full scale. The validity of the results will be established by comparing full-scale and small-scale aspiration-efficiency measurements on a selection of typical dust monitoring inlets.

Work programme: The first step is to develop the scaling methodology and to verify it by means of computational fluid dynamics. Scaled test systems for both calm air and for moving air scenarios will then be constructed. Experiments will be carried out on at least three different scales, simulating different external conditions (e.g. wind speed, orientation). These will provide examples of typical applications for the scaled test systems. The results will be analysed to deduce the range of conditions for which scale-invariance has been obtained. Publications, conference and meeting presentations will be prepared to disseminate the results from the research. State of progress: The project started in December 1998.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Health and Safety Executive (HSE)
Address
Broad Lane
S3 7HQ Sheffield
United Kingdom

Participants (6)

FRAUNHOFER-GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Germany
Address
Nikolai-fuchs-strasse 1
30625 Hannover
INSTITUTE OF OCCUPATIONAL MEDICINE LTD
United Kingdom
Address
Roxburgh Place 8
EH8 9SU Edinburgh
Lund University
Sweden
Address
Ole Roemers V.
221 00 Lund
NATIONAL INSTITUTE FOR WORKING LIFE
Sweden
Address
Warfvinges Vaeg 25
112 79 Stockholm
NATIONAL RESEARCH COUNCIL OF ITALY
Italy
Address
Via P. Gobetti 101
40129 Bologna
UNIVERSITY OF BOLOGNA
Italy
Address
6/2,Viale Berti Pichat 6/2
40127 Bologna