Aspiration characteristics of idealized blunt aerosol samplers at large angles to the wind

Avula Sreenath, Gurumurthy Ramachandran, James H. Vincent

Research output: Contribution to journalArticle

Abstract

The research described in this paper extends the body of work contained in earlier publications in which aerosol sampling aspiration efficiency was studied in a small wind tunnel for simple, idealized sampler geometries. These studies are aimed at providing generic knowledge about the physical and functional behaviors of such systems that can then be generalized to sampling systems of more practical interest. In this paper, attention is focused on the little-researched case of a blunt sampler facing away from the prevailing wind velocity. The results show, that for angles greater than 90° with respect to the wind, aspiration efficiency and particles losses inside the sampler close to the entry are constant as a function of α. This in itself may have some practical usefulness since it enables the definition of a regime of aerosol performance that is relatively "well-behaved". These results are in marked contrast to what has been learned from the same body of work for sampler behavior when facing forward with respect to the wind. Here not only does aspiration efficiency vary sharply with orientation, but so too does the particle entry loss. From this it is concluded that no general model of aspiration efficiency can be available so long as experimental results embody unknown entry loss biases. With this in mind, caution is recommended in field sampling or in laboratory experiments where the measurement does not explicitly include such entry losses.

Original languageEnglish (US)
Pages (from-to)871-881
Number of pages11
JournalJournal of Aerosol Science
Volume33
Issue number6
DOIs
StatePublished - 2002
Externally publishedYes

Fingerprint

Aerosols
sampler
aerosol
Sampling
sampling
wind tunnel
Wind tunnels
wind velocity
geometry
Geometry
loss
Experiments
particle

Keywords

  • Aerosol sampling
  • Aspiration efficiency
  • Blunt bodies

ASJC Scopus subject areas

  • Environmental Chemistry
  • Materials Science(all)
  • Pollution

Cite this

Aspiration characteristics of idealized blunt aerosol samplers at large angles to the wind. / Sreenath, Avula; Ramachandran, Gurumurthy; Vincent, James H.

In: Journal of Aerosol Science, Vol. 33, No. 6, 2002, p. 871-881.

Research output: Contribution to journalArticle

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