Effect of environmental deflector and curtain on air exchange rate in slurry pit in a model pig house

摘要

The main source of ammonia and odour from most livestock buildings is the slurry pit. The ammonia emission rate is affected by the air exchange rate in the slurry pit. Reduction of air exchange between slurry pit and room air may reduce the emissions. The hypothesis that using an environmental deflector in the room and curtains in the slurry pit may affect air exchange rate between the slurry pit and the room air was validated. In the experiment, three position angles for the deflector and three arrangements of curtains were investigated in a two-dimensional ventilation chamber under isothermal conditions at two ventilation airflow rates. The airflow pattern, air velocity and turbulence intensity inside the chamber were also recorded. The results showed that the airflow patterns, air velocities and turbulence intensities in the room space near the slatted floor and in the headspace of the pit were influenced by changing deflector angles and curtain numbers. It was found that the lowest pit ventilation and the highest concentration in the headspace of the pit could be achieved by using a deflector's position angle of 45p at both of two airflow rates. On the other hand, it was also found that more curtain numbers under the slatted floor and lower room ventilation rate caused lowest pit air exchange rate and the highest concentration in the headspace of pit.