With northern pig house as study objective,the 3-D numerical simulation of natural ventilation airflow field of five pig houses with different window area was done by using Fluent software,and the comparative analysis was carried out on simulation result and measured result.The results showed that the effect of ventilation was decided by the reasonable area ratio of window and earth and the ratio of length and width of window.According to this real pig house in experiment,there are the best uniformity of ventilation and the least area of having no ventilation by 1：10 of the area ratio of the window and earth in the pig houses,the smaller air retention zone by the smaller ratio of length and width of window,the better effect of ventilation;the results of simulation agree well with the results of measured,the max relative error and the average error was 11.1% and 7.7%,so the software of Fluent was proved effective in the numerical simulation of natural ventilation in the pig houses and the optimal design of pig houses＇ structure.
