沈阳地区低屋面横向通风牛舍空气CFD数值模拟

发布时间：2018-05-16 22:20

  本文选题：低屋面横向通风牛舍 + 数值模拟　； 参考：《沈阳工业大学》2016年硕士论文

【摘要】：随着奶牛养殖业的发展,奶牛的散养和传统牛舍的圈养方式已经不能满足现代畜牧业的要求,2005年美国建成第一栋低屋面横向通风牛舍。低屋面横向通风牛舍能够满足大批量养殖奶牛的要求,但是这种牛舍存在以下三个方面的问题:一是牛舍内的空气流场不均匀;二是在夏季给牛舍通风时空气交换率通常在60s~120s的经验范围内取值,不够精确;三是在冬季时在寒冷地区给牛舍通风会造成牛舍内空气温度过低,引发奶牛冻伤等健康问题。本课题采用FLUENT软件对牛舍的不同形式建立模型进行模拟分析。本课题首先针对不同挡风板角度(分别取值30°、60°和90°)建立了三种牛舍模型,并通过FLUENT软件对这三种模型进行了速度场的模拟,通过对模拟结果的分析比较找出了最优的挡风板角度;其次,通过FLUENT软件模拟了夏季牛舍在60s、80s、100s和120s四种空气交换率情况下的室内流场,通过比较牛舍内的空气温度、气流速度和CH4浓度的分布情况来找出最佳的空气交换率;最后,通过FLUENT软件分别模拟冬季牛舍在启闭天窗两种情况下和开启天窗时采用不同的送风温度的情况,通过比较其模拟结果,找到冬季时最优的通风形式。通过对FLUENT软件的模拟结果进行分析研究,得出牛舍挡风板的最佳倾斜角度为30°;在夏季时,牛舍通风的最佳空气交换率为80s;在冬季时,开启天窗的牛舍比关闭天窗的牛舍通风效果好,节省加热量,并且开启天窗的牛舍内温度分布更均匀,在冬季通风室外计算温度下通过对侧面进风加热将侧面送风温度提升到4℃可以维持冬季牛舍内温度高于零度。本课题的研究可以为寒冷地区低屋面横向通风牛舍的优化设计和通风运行调节提供参考。
[Abstract]:With the development of the dairy cattle breeding industry, the loose raising of dairy cows and the way of the traditional cattle sheds in captivity can no longer meet the requirements of modern animal husbandry. In 2005, the first low roof ventilated cattle shed was built in the United States. The low roof crosswise ventilated cowshed can meet the requirements of large quantities of dairy cattle, but there are three problems in this kind of cattle house: first, the air flow field in the cattle shed is uneven; The other is that the air exchange rate is usually taken within the experience range of 60s~120s when ventilating the cowshed in summer, and the third is that ventilating the cowshed in the cold area in winter will cause the low air temperature in the cowshed and lead to the health problems such as frostbite and so on. In this paper, FLUENT software is used to simulate and analyze the different models of cowshed. In this paper, three kinds of cowshed models are established for different windshield angles (30 掳~ 60 掳and 90 掳) respectively, and the velocity fields of these models are simulated by FLUENT software. Through the analysis and comparison of the simulation results, the optimum angle of the windshield is found. Secondly, the indoor flow field of the summer cowshed under the conditions of 60 s, 80 s, 100 s and 120 s of air exchange rate is simulated by FLUENT software, and the air temperature in the cattle house is compared. The distribution of air velocity and CH4 concentration is used to find out the best air exchange rate. Finally, FLUENT software is used to simulate the different air supply temperature in winter cowshed under the two conditions of opening and closing the skylight and opening the skylight, respectively. By comparing the simulation results, the optimal ventilation in winter is found. By analyzing the simulation results of FLUENT software, it is concluded that the optimum inclination angle of the windshield is 30 掳, the optimum air exchange rate of the cowshed ventilation is 80 s in summer, and the optimum air exchange rate is 80 s in winter. The cowshed that opens the skylight is better ventilated than the barn with the skylight closed, saves more heat, and the temperature distribution in the barn that opens the skylight is more uniform. The side air supply temperature can be raised to 4 鈩，

本文编号：1898660