温室大跨度薄膜风筒送风特性模拟及试验研究  

Simulation and experimental study of the air distribution characteristics of large-span film air duct in greenhouses

作　　者：陆绪颖 余春江[1] LU Xuying;YU Chunjiang(College of Energy Engineering,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学能源工程学院,杭州310027

出　　处：《农业工程学报》2024年第15期204-211,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点研发计划项目(2022YFB4202004)。

摘　　要：现代大型温室普遍使用送风末端为长距离柔性薄膜风筒的空气处理机组(air handling unit,AHU)作为温度控制功能单元来完成大空间内的热量输送。为探究此类风筒AHU的性能,该研究采用理论分析和数值模拟方法研究其送风特性,并通过试验验证计算模型的正确性。结果显示,薄膜风筒内不同截面的静压在开孔部位急剧减低至0,同时气流速度明显增加,但是影响范围不大,对风筒内的压力场和流场影响较小。在风筒同一截面上不同开孔位置流出的气体速度和速度分布基本一致,以风筒入口端风速2.45 m/s为例,在风筒60.06 m处风筒壁开孔处气流最大速度为5.64 m/s,位于开孔中心处,并垂直与开孔平面向外流动,速度分布为中心流速最高,越靠近孔边缘流速越低。对风筒沿长度方向通过筒壁各开孔流出的风量进行计算发现,在不同风筒入口风速条件下送风量基本保持恒定,均匀性系数均大于0.92,说明此类风筒能够沿长度方向均匀地配送气流,可将热量或者冷量在温室大空间内进行均匀投送,从而为现代大型温室内空间内维持温度场均匀提供保障。Air handling units(AHUs)with long distance flexible film air ducts are commonly adopted in modern large-scale greenhouses for temperature controlling.To study the performance of this type of AHU,theoretical analysis and numerical simulation methods were used to discover its air supply characteristics,and a full-scale experiment was carried out to verify the correctness of the calculation model.The calculation showed that the static pressure of different cross-sections in the thin film air duct sharply decreased to 0 at the small-hole opening,where the airflow velocity increased significantly.However,this influence only exists locally and had little effect on the pressure and gas velocity fields inside the wind duct.The velocity and velocity distribution of the gas flowing out from different openings on the same section of the wind duct are basically the same.Taking the wind speed of 2.45 m/s at the inlet end of the wind duct as an example,the maximum velocity of the airflow at the opening position of the wind duct wall at 60.06 m is 5.64 m/s,located at the center of the opening and flowing outward perpendicular to the opening plane.The velocity distribution is that the center has the highest velocity,and the closer to the edge of the hole,the lower the velocity.The volum of the airflow flowing out through the openings on the wall of the wind duct along the length direction shows that the air supply remains basically constant under different inlet wind speed conditions,and the uniformity coefficient is greater than 0.92.This indicates that this type of AHU can evenly distribute airflow along the length direction,and can evenly distribute heat or cold in the large space of the greenhouse,thus providing a guarantee for maintaining a uniform temperature field in modern large greenhouses.

关 键 词：温室 温度控制 CFD 数值模拟 薄膜风筒 长距离 送风均匀性 

分 类 号：S625.51[农业科学—园艺学]