茶园高架风扇防霜系统设计与试验

摘要:

早春倒春寒气候条件下，茶树遭受严重的晚霜冻害，造成茶叶产量和品质的下降。在分析倒春寒逆温气象特点的基础上，研究了将近地上方高温空气与近地低温空气混合，实现防霜的作用机理；总体设计了以轴流风扇为核心部件的高架风扇防霜系统；对系统作用区域的风速分布特征、温度分布和温升效果，进行了试验研究。结果表明，一套功率3 kW的风扇防霜系统有效覆盖面积大于1 000 m2，在外界气温-4℃的霜冻条件下，可提高冠层温度4℃，能够有效预防消除茶园晚霜冻害。

Abstract:

Under the condition of late spring cold in early spring, tea plant suffers much damaged by frost, which causes low production and quality. On this occasion, temperature inversion occurs, which can be utilized to push upper warmer air downward to the cold tea plants so as to increase the temperature of tea canopy and prevent frost damage. Based on the principle, elevated wind machine system for frost protection was designed, of which axial-flow fan was a key component. The control sub-system was developed to make the whole system automatic start or stop based on the difference between the upper and lower temperature. Experiments were conducted to test effective range and frost protection effects. The results showed that one system of 3 kW power could cover effective range of 1 000 m2 and increased temperature by 4℃ around tea canopy when ambient temperature was about -4℃. Therefore, the developed elevated wind machine system can effectively prevent frost damage. 