On Finding the Right Sampling Line Height through a Parametric Study of Gas Dispersion in a NVB

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