集中通风式分娩母猪舍温湿度数值模拟与试验验证

为研究集中通风式猪舍温湿度场的分布规律，利用计算流体力学技术，对云南省某规模猪场的地沟进风、中央排风式分娩母猪舍进行温湿度场耦合模拟研究，并通过试验进行验证。本研究采用四面体非结构网格进行网格划分，运用重整化群RNG k-ε湍流模型进行稳态模拟，通过实测值与模拟值的对比，对模型进行验证。研究结果表明，温度模拟值与实测值最大差值不超过4 ℃，平均相对误差为6.5%；相对湿度模拟值与实测值最大差值不超过10%RH，平均相对误差为7.3%，验证了模型的准确性。温度、相对湿度和风速在垂直高度上的分布差异较大，温度随着垂直高度的增加而增加，且温度梯度逐渐增大；相对湿度随着垂直高度的增加而减小；而风速则随着垂直高度的增加而逐渐减小。本研究揭示了集中通风式分娩母猪舍的温湿度场分布规律，并为分娩舍温湿度场的优化提供参考。

Numerical simulation and experimental verification of temperature and humidity in centralized ventilated delivery pigsty

High requirements for the environment are needed for pigs in the delivery house. This paper aimed to study the distribution of temperature and humidity in a centralized ventilated delivery house by numerical simulation. Tetrahedral non-structural meshes were used for mesh division, and the RNG k-ε turbulence model with high precision was used for steady-state simulation. The results showed that the maximum difference between the simulated temperature and the measured temperature was less than 4 ℃, and the relative error was 0.44% to 17.04%, while the average relative error was 6.5%. The maximum difference between simulated humidity and measured humidity is less than 10%, and the relative error was 0 to 13.9%, while the average relative error was 7.3%. The simulated value of temperature was smaller compared with the measured value, while the simulated value of relative humidity was larger than the tested value. It could be seen from the Z cross-section that in the horizontal position of each section, the temperature gradually increased with the increase of height, and the median line of the aisle was taken as the axis of symmetry. The temperature distribution of each longitudinal section presented an obvious symmetry, indicating that the temperature distribution in the dormitory was consistent on both sides of the aisle. The relative humidity of each section decreases gradually with the increase of height. The relative humidity of the air inlet area at the bottom was above 90%. The closer it was to the middle passage, the relative humidity tends to decrease, but the decrease was not obvious. The relative humidity in the passage was above 80%. The wind speed of the longitudinal section in the shed could meet the requirements of the national standards. Even in the position of the inlet with high wind speed, the wind speed was maintained below 0.4 m/s. According to the airflow distribution of the horizontal section and the longitudinal section, there was no airflow dead zone below the height of the pigs in the shed. At the same time, the closer the pig was to the fan, the greater the longitudinal airflow, but the speed of the airflow was below the national standard. In the plane (X cross-section) on both sides of the aisle, the temperature had an obvious distribution gradient in the horizontal height, while in the plane of the aisle, the temperature was evenly distributed in the horizontal height, mainly maintained at 23-24 ℃, and the air outlet temperature was about 24 ℃. Contrary to the temperature distribution law in the X cross-section, the relative humidity in each section gradually decreased with the increase of height, and the distribution range was mainly between 80% and 100%. From the cross-sections on both sides of the corridor, it could be found that there was a small jet beside the pigs, and the jet direction pointed to the fan bearing, indicating that the effect of negative pressure ventilation was significant, which played a strong drag role on the airflow direction in the shed. On the far side of the fan, the influence range of negative pressure exhaust was greater than that on the near side of the fan. Simulated values had a great agreement with experimental values. The study revealed the temperature and humidity distribution of the delivery house and provided a better reference for the optimization of the temperature and humidity distribution of the delivery house.