CFD modelling of an animal occupied zone using an anisotropic porous medium model with velocity depended resistance parameters
CFD modelling of an animal occupied zone using an anisotropic porous medium model with velocity depended resistance parameters
复制标题
使用具有速度相关阻力参数的各向异性多孔介质模型对动物占据区域进行 CFD 建模
DOI：
10.1016/j.compag.2020.105950
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Sabrina Hempel
中科院分区：
文献类型：
--
作者：
E. M. Doumbia;D. Janke;Qianying Yi;T. Amon;M. Kriegel;Sabrina Hempel
奶牛舍内的气流受到多种因素的影响，如牛舍的几何形状、天气条件、开口的配置、奶牛作为热源、流动障碍等。计算流体动力学（CFD）具有提供详细的气流信息和允许完全控制边界条件的优点，因此广泛应用于畜牧业建筑研究。然而，由于计算能力有限，众多动物很难进行详细设计。因此，需要开发和使用智能数值模型，以降低所需的计算能力，同时保持相当的精度水平。在这项工作中，多孔介质建模被认为是使用 Ansys Fluent 来解决这个问题。对随机排列的22个简化奶牛几何模型（CM）填充的动物占据区（AOZ）与其多孔介质模型（PMM）进行了比较。 PMM 的各向异性行为在多孔模型中实现，以考虑湍流影响。域入口处的速度从 0.1 m s−1 到 3 m s−1 变化，动物和进入空气之间的温差设置为 20 K。导致理查森数 Ri 对应于三种类型的传热对流，即自然对流、混合对流和强制对流。研究发现，两个模型（奶牛几何模型和 PMM）之间的压降差异约为 2%，而对流传热差异则小于 6%。此外，通过农场测量的速度场验证，显示了具有速度自适应压降和传热系数的参数化 PMM 的实用性。
The airflow in dairy barns is affected by many factors, such as the barn’s geometry, weather conditions, configurations of the openings, cows acting as heat sources, flow obstacles, etc. Computational fluids dynamics (CFD) has the advantages of providing detailed airflow information and allowing fully-controlled boundary conditions, and therefore is widely used in livestock building research. However, due to the limited computing power, numerous animals are difficult to be designed in detail. Consequently, there is the need to develop and use smart numerical models in order to reduce the computing power needed while at the same time keeping a comparable level of accuracy.In this work the porous medium modeling is considered to solve this problem using Ansys Fluent. A comparison between an animal occupied zone (AOZ) filled with randomly arranged 22 simplified cows’ geometry model (CM) and the porous medium model (PMM) of it, was made. Anisotropic behavior of the PMM was implemented in the porous modeling to account for turbulence influences. The velocity at the inlet of the domain has been varied from 0.1 m s−1to 3 m s−1and the temperature difference between the animals and the incoming air was set at 20 K. Leading to Richardson numbers Ri corresponding to the three types of heat transfer convection, i.e. natural, mixed and forced convection. It has been found that the difference between two models (the cow geometry model and the PMM) was around 2% for the pressure drop and less than 6% for the convective heat transfer. Further the usefulness of parametrized PMM with a velocity adaptive pressure drop and heat transfer coefficient is shown by velocity field validation of an on-farm measurement.