TWO–DIMENSIONAL COMPUTATIONAL FLUID DYNAMICS (CFD) MODELING OF AIR VELOCITY AND AMMONIA DISTRIBUTION IN A HIGH–RISETM HOG BUILDING –4050.

Abstract

Computational fluid dynamics (CFD) models of a HighRiseTM hog building (HRHB) were developed to simulateair velocity and ammonia distribution within the building under minimum ventilation conditions. Because bothlaminar/transient and turbulent flow conditions exist in the building, two different flow simulations were used. Air velocityprofiles from both turbulent and laminar flow models indicated that some air moves from the lower to the upper level, whichaffects the distribution of ammonia in the pig space. The simulation results were compared to air velocities and ammoniaconcentrations measured within an experimental HRHB. The turbulent flow model more closely matched measured ammoniavalues at locations in the HRHB than the laminar flow model. Using the turbulent flow model, ammonia concentration in thepig space would be below 25 ppm, and the NH3 emission factor for the HRHB during winter (low ventilation) conditions wouldbe 4.6 kg pig1 yr1. Although limited by the representation of real building geometry and processes, the twodimensional CFDmodels allowed rapid simulation of airflow and species gradients in the HRHB.