Development of CFD model for Predicting Ventilation Rate based on Age of Air Theory using Thermal Distribution Data in Pig House
2017
Kim, R., Seoul National University, Seoul, Republic of Korea | Lee, I., Seoul National University, Seoul, Republic of Korea | Ha, T., Seoul National University, Seoul, Republic of Korea | Yeo, U., Seoul National University, Seoul, Republic of Korea | Lee, S., Seoul National University, Seoul, Republic of Korea | Lee, M., Seoul National University, Seoul, Republic of Korea | Park, G., Seoul National University, Seoul, Republic of Korea | Kim, J., Seoul National University, Seoul, Republic of Korea
The tracer gas method has an advantage that can estimate total and local ventilation rate by tracing air flow. However, the field measurement using tracer gas has disadvantages such as danger, inefficiency, and high cost. Therefore, the aim of this study was to evaluate ventilation rate in pig house by using the thermal distribution data rather than tracer gas. Especially, LMA (Local Mean Age), which is an index based on the age of air theory, was used to evaluate the ventilation rate in pig house. Firstly, the field experiment was conducted to measure micro-climate inside pig house, such as the air temperature, CO₂ concentration and wind velocity. And then, LMA was calculated based on the decay of CO₂ concentration and air temperature, respectively. This study compared between LMA determined by CO₂ concentration and air temperature; the average error and root mean square error were 3.76 s and 5.34 s. From these results, it was determined that thermal distribution data could be used for estimation of LMA. Finally, CFD (Computational fluid dynamic) model was validated using LMA and wind velocity. The mesh size was designed to be 0.1 m based on the grid independence test, and the Standard k-ω model was eventually chosen as the proper turbulence model. The developed CFD model was highly appropriate for evaluating the ventilation rate in pig house.
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