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| Flow field characteristics of wet curtain and fan in multi-span greenhouse |
| GAO Zhenjun1, LI Wengyang1, DING Xiaoming2*, LI Wei3, Nyam-Osor Batkhuu4 |
| 1. College of Mechanical and Power Engineering, China Three Gorges University, Yichang, Hubei 443002, China; 2. Key Laboratory of Agricultural Facilities Structural Engineering, Ministry of Agriculture and Ruralareas, Beijing 100125, China; 3. Guangdong Institute of Modern Agricultural Equipment, Guangzhou, Guangdong 510630, China; 4. Department of Forest Environmental Science, National University of Mongolia, Ulaanbaatar 14201, Mongolia |
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Abstract 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.
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Received: 07 October 2021
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