Publication Database

On finding the right sampling lines height through a parametric study of gas dispersion in a NVB (2021)

Art

Zeitschriftenartikel / wissenschaftlicher Beitrag

Autoren

Doumbia, E. Moustapha

Janke, David

Yi, Qianying

Zahng, Guoqiang

Amon, Thomas (WE 10)

Kriegel, Martin

Hempel, Sabrina

Quelle

Applied Sciences : open access journal

Bandzählung: 11

Heftzählung: 10

Seiten: Artikel 4560

ISSN: 2076-3417

Sprache

Englisch

Verweise

URL (Volltext): https://www.mdpi.com/2076-3417/11/10/4560

DOI: 10.3390/app11104560

Kontakt

Institut für Tier- und Umwelthygiene

Robert-von-Ostertag-Str. 7-13
14169 Berlin
+49 30 838 51845
tierhygiene@vetmed.fu-berlin.de

Abstract / Zusammenfassung

The tracer gas method is one of the common ways to evaluate the air exchange rate in a naturally ventilated barn. One crucial condition for the accuracy of the method is that both considered gases (pollutant and tracer) are perfectly mixed at the points where the measurements are done. In the present study, by means of computational fluids dynamics (CFD), the mixing ratio NH3/CO2 is evaluated inside a barn in order to assess under which flow conditions the common height recommendation guidelines for sampling points (sampling line and sampling net) of the tracer gas method are most valuable. Our CFD model considered a barn with a rectangular layout and four animal-occupied zones modeled as a porous medium representing pressure drop and heat entry from lying and standing cows. We studied three inflow angles and six combinations of air inlet wind speed and temperatures gradients covering the three types of convection, i.e., natural, mixed, and forced. Our results showed that few cases corresponded to a nearly perfect gas mixing ratio at the currently common recommendation of at least a 3 m measurement height, while the best height in fact lied between 1.5 m and 2.5 m for most cases.