Effects of Different Ventilation Modes and Outlet Height on Nursery Piggery Environment

In order to study the effects of ventilation modes and outlet height on the airflow field of a nursery piggery,computational fluid dynamics （CFD） technology was used to simulate the wind speed and temperature of an experimental pig house in the cold northern region.This study was conducted with simulation and a comparative analysis of transverse ventilation,longitudinal ventilation and roof air intake modes.Furthermore,the effects of the air outlet height of 0.7,0.6 and 0.5 m with the roof air inlet mode on the environment in the pig house were studied.Field experiments verified the model of roof air intake model.The results showed inadequate ventilation in both the vertical and horizontal ventilation.However,the airfield gradients were less variable and more balanced when using the rooftop air intake mode.The variation of outlet height significantly affected nursery pig houses’ airflow velocity and temperature.Roof air inlet mode with an outlet height of 0.7 m was better than the other two.The normalized mean square error （NMSE） of air velocity and temperature was less than 0.01,and the simulation analysis could genuinely reflect the distribution of the airflow field in the nursery.