Computational Fluid Dynamics Study on the Influence of Airflow Patterns on Carbon Dioxide Distribution in a Scaled Livestock Building:

Airflow patterns and airflow rate have an important influence on contaminant distribution in livestock buildings. The objective of this paper is to model and evaluate the effect of airflow rates and airflow patterns effect on CO₂ concentration distribution and emission rates in a scaled livestock building with slatted floor. Contaminant sources are assumed to be modelled as a constant concentration on the manure surface. Three different ventilation rates and two different deflector degrees are studied, in which the deflector is applied to change the airflow patterns. A CFD commercial software code has been applied to simulate the contaminant distribution. Experiments of tracer gas concentration distribution in the chamber are performed at Air Physic Lab of Aarhus University to validate CFD software. Simulation results and measurements show that ventilation rates and airflow patterns have an effect on the contaminant distribution within the room. The non-dimensional CO₂ concentration along the horizontal direction above the slatted floor varies largely which means the emission rate is related to the local velocity. With increasing airflow rate, the emission rate of CO₂ and average mass transfer coefficient will increase. The influence of the deflector on the emission rate is also shown.