The Simulation Analysing Of Typical Piggery’s Natural Ventilation Under Different Window Layout

With the development of animal husbandry, the methods of animal buildings construction also attract the attention of farmers. The requirement of the animal building will reach a new high level. At present, most of the livestock and poultry farms apply the intensive cultivation method. In this type of structure, the ventilation almost only depends on the machines for the sealed form. Although this type of animal building could meet the base need of the growing of livestock, the cost of farming is really high. On the current terms of the breeding industry, most of which are small and medium farmers. Therefore, the lower-cost type of animal building is the optimum. This type of animal building cut down the costing by using natural ventilation. What’s more, this type of animal building can protect the environment by reducing the use of non-renewable resources.The air flow condition in the animal building has a significant impact on indoor air temperature, humidity, distribution of harmful gas. So the air flow condition plays a key role in the productivity of livestock. In this paper, different types of models are constructed to simulate the natural ventilation with the help of CFD and ANSYS software. As a consequence, the valid and reasonable theoretical foundation for the construction of animal building is provided.According the theoretical basis computational fluid dynamics (CFD), this paper simulate two-dimensional steady-state airflow field inside the hog house by using Navier-Stokes equations and RNG turbulence model with the help of ANSYS. The results of this research are provided as follows:1. For the same type of piggery(1) As for the same window arrangement the natural airflow within the pigsty changes with the aperture ratio. By comparing various air speed diagram and vector diagram under different aperture ratio, the conclusion that the greater the aperture ratio the more natural ventilation is got.(2) As for piggery with same aperture ratio,①the natural airflow within the piggery changes with the layout of window. From the comparison under CASE3and CASE2layout, increasing the number of inhalation windows is more useful than increasing the number of expiration windows,②the natural airflow within the piggery changes with the number of windows. From the comparison under CASE1and CASE4layout, the study show the result that the more windows the better the arrangement of air flow.2. For the different type of piggeryThis study compares the ventilation in different type of piggery with CASE4window layout, the results of comparison are provided as follows:(1) For the piggery without skylight window, the piggery with flat roof has better performance in ventilation than others. The cross ventilation in the piggery is help for move out the dirty air.(2) For the piggery with skylight window, the piggery with half-belfry roof has better performance in ventilation than belfry roof piggery. Under the influence of smokestack, the piggery with belfry roof conform an area without air flow.From the result of comparison, as for the pig house of natural ventilation, the flat roof and half bell tower roof are the optimal chooses. According the analysis above, those types of piggery have superiority in ventilation. The CASE4is the optimum window form for the advantage of increasing the intake air and forming an excellent air movement organization.