射流通风室内气流组织的数值研究

发布时间：2018-07-21 13:19

【摘要】：调查表明，人员有80%以上的时间是在室内度过的，因此有必要研究高效的通风方式，为人员营造健康舒适的室内环境。置换通风提高了房间的通风效率，但存在冬季使用受限等技术问题；而射流通风不仅可以营造出类似于置换通风的气流组织效果，亦可全季节运行，尤其适用于办公建筑的机械通风。因此，本文以射流通风技术为研究点，对其多工况下的室内气流组织特性及影响因素进行了数值模拟研究。 首先，建立了射流通风的物理模型，并对所选择的湍流模型、压力差值格式和壁面条件处理方法拟合9种不同的定解条件进行数值模拟研究，基于前期学者的实验数据验证模型的正确性；其次，分向室内送冷风和热风两种工况，对碰撞射流通风和竖壁贴附射流通风下室内气流组织特性进行了模拟实验研究，并与置换通风进行对比研究，从室内气流组织分布特性和通风效率两个层面，分析了基于射流通风的室内温度场、速度场、空气龄、空气分布不均匀系数、能量利用系数、空气分布特性指标等的变化规律；最后，对影响碰撞射流通风和竖壁贴附射流通风的关键因素进行了研究，建立了送回风口模型，探讨了送回风口不同布置形式对射流通风效果的影响，归纳出最佳的送回风口布置方案。 研究表明，对于室内气流组织，采用湍流的RNG k-ε模型、标准壁面函数法和Body-force-weighted压力差值格式可以取得较好的数值模拟结果； 研究发现，射流通风向室内送冷风时，室内温度场有明显的分层现象，和置换通风相比，碰撞射流通风使房间地面“空气湖”的温度高出2℃，竖壁贴附射流通风使房间地面“空气湖”的温度高出3℃；室内空气龄纵向分层现象明显，和置换通风相比，房间z=1.2m平面以下的空气龄与置换通风类似，房间z=1.2m平面以上的空气龄在比置换通风低100~200s，空气品质较好。当向室内送热风时，射流通风方式可使室内z=0.1m平面以下的温度比上部的温度高出1~2℃，整个流场的空气龄分布无明显的分层现象。 研究还发现，，碰撞射流通风和竖壁贴附射流通风夏季工况下能量利用系数为2.021和1.609，冬季工况下为1.08和1.21，均大于1，存在节能空间，并且夏季节能空间较大。射流通风下室内气流组织的分布与送、回风口的布置有较大的关系。
[Abstract]:The investigation shows that more than 80% of the time is spent indoors, so it is necessary to study the efficient ventilation method to create a healthy and comfortable indoor environment for the personnel. Displacement ventilation improves the ventilation efficiency of the room, but there are some technical problems such as limited use in winter, and jet ventilation can not only create the effect of airflow organization similar to displacement ventilation, but also run all season. Especially suitable for mechanical ventilation of office buildings. Therefore, this paper takes jet ventilation technology as the research point, and carries on the numerical simulation research to the indoor airflow organization characteristic and the influence factor under the multi-working condition. First of all, the physical model of jet ventilation is established, and the selected turbulence model, pressure difference scheme and wall condition processing method are used to simulate nine different definite solution conditions. Based on the experimental data of previous scholars, the validity of the model is verified. Secondly, the indoor airflow distribution characteristics under impact jet ventilation and vertical wall attached jet ventilation are simulated. Compared with the displacement ventilation, the indoor temperature field, velocity field, air age, air distribution uneven coefficient and energy utilization coefficient are analyzed from two aspects of indoor air distribution characteristics and ventilation efficiency, including the indoor temperature field, velocity field, air age, air distribution and energy utilization coefficient based on jet ventilation. Finally, the key factors influencing the ventilation of impact jet and vertical wall attached jet are studied, and the model of return tuyere is established. The influence of different layout forms of return tuyere on the effect of jet ventilation is discussed, and the best layout scheme of return tuyere is concluded. The results show that the RNG k- 蔚 model of turbulence, the standard wall function method and the Body-force-weighted pressure difference scheme can obtain good numerical simulation results for indoor airflow. The indoor temperature field has obvious stratification phenomenon. Compared with the displacement ventilation, the air lake temperature of the room floor is 2 鈩

本文编号：2135651