连栋温室内湿帘-风机流场特性

为了解华南地区大型连栋玻璃温室在湿帘-风机通风条件下温度场与速度场的变化情况,探究该通风方式下,温室内的通风降温性能,以广州市农业技术推广总站示范基地的连栋玻璃温室为研究对象分别进行了稳态和瞬态计算,将稳态模型的计算结果与温室内监测点得到的数据进行对照,验证了计算模型的可靠性,并对湿帘-风机通风工况进行瞬态计算,得到温室内直观的温度和速度的分布情况及变化规律.结果表明:开启湿帘-风机系统后,湿帘侧最初风速可达1.6 m/s,通风过程中逐渐发展为从湿帘入口贯通风机出口的高速气流场,气流速度最终稳定在0.8 m/s;温室内温度场从湿帘侧到风机侧表现出梯度降温的变化特征,同时伴随着温室全局性的微小幅度降温;将风机流量增加1倍后,温室内气流的湍动程度增加,降温速度明显提高.得到的结果将为华南地区连栋玻璃温室的正常运行和精准调控温室内的小气候环境提供参考.

Flow field characteristics of wet curtain and fan in multi-span greenhouse

In order to understand the changes in the temperature field and velocity field of the large-scale multi-span solar greenhouse in southern China under the conditions of curtain-fan ventilation, and to explore the ventilation and cooling performance in the greenhouse under this ventilation method, taking the large-scale multi-span solar greenhouse in the Demonstration Base of Guangzhou Agricultural Technology Extension Station as the research object, the steady-state and transient calculations were carried out. The multi-span solar greenhouse established a three-dimensional steady-state and transient calculation model for the research object. The calculation results of the steady-state model are compared with the data obtained from the monitoring points in the greenhouse to verify the reliability of the calculation model, and the transient calculation of the wet curtain-fan ventilation conditions is carried out, and the intuitive temperature and speed distribution and change rules in the greenhouse are obtained. The results show that after the wet curtain-fan system is started, the wind speed on the side of the wet curtain can reach 1.6 m/s in the ventilation process, it gradually develops into a high-speed airflow field from the entrance of the wet curtain to the outlet of the ventilator, and the airflow speed is finally stable at 0.8 m/s. The temperature field in the greenhouse shows the characteristics of gradient cooling from the side of the wet curtain to the side of the fan, and it is accompanied by a slight global cooling of the greenhouse. After doubling the flow rate, the turbulence during the development of the velocity field increases, and the cooling speed increases significantly. The results will provide a reference for the normal operation of the multi-span solar greenhouse in South China and the precise control of the microclimate environment in the greenhouse.