Two-dimensional computational fluid dynamics (CFD) modeling of air velocity and ammonia distribution in a high-rise hog building

摘要

Computational fluid dynamics (CFD) models of a High-Rise{sup}TM hog building (HRHB) were developed to simulate air velocity and ammonia distribution within the building under minimum ventilation conditions. Because both laminar/transient and turbulent flow conditions exist in the building, two different flow simulations were used. Air velocity profiles from both turbulent and laminar flow models indicated that some air moves from the lower to the upper level which affects the distribution of ammonia in the pig space. The simulation results were compared to air velocities and ammonia concentrations measured within an experimental HRHB. The turbulent flow model more closely matched measured ammonia values at locations in the HRLIB than the laminar flow model. Using the turbulent flow model ammonia concentration in the pig space would be below 25 ppm, and the NH{sub}3 emission factor for the HRHB during winter (low ventilation) conditions would be 4.6 kg pig{sub}-1 yr{sub}-1. Although limited by the representation of real building geometry and processes, the two-dimensional CFD models allowed rapid simulation of airflow and species gradients in the HRHB.