蒋蘋, 杨希文, 罗亚辉, 龙莉霞, 石毅新, 胡文武. 蔬菜气雾栽培箱不同气流循环方式的流场和温度场CFD模拟[J]. 农业工程学报, 2019, 35(16): 233-241. DOI: 10.11975/j.issn.1002-6819.2019.16.026
    引用本文: 蒋蘋, 杨希文, 罗亚辉, 龙莉霞, 石毅新, 胡文武. 蔬菜气雾栽培箱不同气流循环方式的流场和温度场CFD模拟[J]. 农业工程学报, 2019, 35(16): 233-241. DOI: 10.11975/j.issn.1002-6819.2019.16.026
    Jiang Pin, Yang Xiwen, Luo Yahui, Long Lixia, Shi Yixin, Hu Wenwu. CFD simulation of flow field and temperature field of different air flow circulation modes in vegetable aeroponics cultivation box[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(16): 233-241. DOI: 10.11975/j.issn.1002-6819.2019.16.026
    Citation: Jiang Pin, Yang Xiwen, Luo Yahui, Long Lixia, Shi Yixin, Hu Wenwu. CFD simulation of flow field and temperature field of different air flow circulation modes in vegetable aeroponics cultivation box[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(16): 233-241. DOI: 10.11975/j.issn.1002-6819.2019.16.026

    蔬菜气雾栽培箱不同气流循环方式的流场和温度场CFD模拟

    CFD simulation of flow field and temperature field of different air flow circulation modes in vegetable aeroponics cultivation box

    • 摘要: 蔬菜气雾栽培箱内的空气流动和温度对箱体内的环境调节及农作物生长具有重要作用,农作物周围空气的均匀性流动能促进农作物的生长速率。为探究蔬菜气雾栽培箱内流场及温度场分布规律,基于计算机流体力学(CFD,computational fluid dynamics)方法,利用FLUENT软件,结合标准湍流模型、有孔介质模型、作物冠层质热交换模型等,建立了蔬菜气雾栽培箱不同气流循环方式下的CFD模型。并对气雾栽培箱内的环境进行优化设计,设计了3种气流循环方案:顶面进侧面出,侧面进顶面出,侧面进侧面出。对送回风口的不同位置布局进行了研究,并对3种气流循环方案进行了数值模拟。模拟结果可知:气流为顶面进侧面出方案中,风速位于生菜生长适宜风速值区域占58.1%,适宜温度值区域占93.6%,通风死角区域占比0.844%;气流为侧面进顶面出方案中,生菜生长适宜风速值区域占59.6%,适宜温度值区域占99.98% ,通风死角区域占比0.069%;气流为侧面进侧面出方案中,风速位于生菜生长适宜风速值区域占54.3%,适宜温度值区域占92.4%,通风死角区域占比16.7%。分析对比后得到侧面进顶面出为最佳气流循环方案。并对此进行了试验测试,结果表明:气雾栽培箱内温度、风速模拟值和实测值进行对比,温度平均相对误差为3.9%,均方根误差为0.86℃。风速平均相对误差为3.5%,均方根误差为0.26 m/s,模拟值和实测值误差较小,模拟效果良好,验证了CFD模型的准确性。该研究为蔬菜气雾栽培箱内的流场及温度变化规律,内部环境调节,装置优化设计提供了参考依据。

       

      Abstract: The air flow and temperature in the vegetable aeroponics cultivation box play an important role in the internal environment regulation and crop growth. The uniform air flow around crops can promote the growth rate of the crop. In order to study the distribution of flow field and temperature field in vegetable aeroponics cultivation box, CFD models of vegetable aeroponics cultivation box under different air flow circulation modes were established based on computational fluid dynamic (CFD) method, FLUENT software, standard turbulence model, porous medium model, crop canopy heat exchange model. The environment in the aeroponics cultivation box was optimized, and three air flow circulation schemes were designed(air flows from top to side, side to top and side to side). The layout of the different positions of the return air outlets was studied, and the numerical simulations of the three air flow circulation schemes were carried out. The simulation results showed that in the scheme of air flow entering from the top and exiting from the side, the suitable wind speed value area of lettuce accounts for 58.1%, the suitable temperature value area accounts for 93.6%, and the ventilation dead zone area accounts for 0.844%. In the scheme of air flow side entering and exiting the top surface, the suitable wind speed value area of lettuce accounts for 59.6%, the suitable temperature value area accounts for 99.98%, and the ventilation dead zone area accounts for 0.069%. In the scheme of air flow side entering side exit, the suitable wind speed value area for lettuce growth accounts for 54.3%, the suitable temperature value area accounts for 92.4%, and the ventilation dead zone area accounts for 16.7%. After comparison, the side entering the top surface was obtained as the optimal air circulation scheme. The temperature and wind speed simulation values and measured values in the aeroponics cultivation box were compared. The results showed that the average temperature relative error was 3.9% and the root mean square error was 0.86℃. The average relative error of wind speed was 3.5%, and the root mean square error was 0.26 m/s. The error between simulated and measured values was small, and the simulation effect was good. The accuracy of the CFD model was verified. In crop cultivation, aeroponics was a new cultivation method in the field of soilless cultivation, which could be applied to greenhouses, plant factories, family balconies and other places through microclimate control technology. In this paper, by regulating the wind speed in the aeroponics box, the climate growth environment and temperature uniformity of the crops can be ensured, and the problems of the roots and canopies of the crops can be effectively solved, and the crop yield and quality can be improved. Airflow velocity and temperature are important factors for crop growth in aeroponics boxes, which affect the transpiration and photosynthesis of crops. Therefore, it is of great significance to study the changes of air velocity and temperature to promote air aeroponics technology. This study provides a reference for the flow field and temperature change law in vegetable aeroponics cultivation box, internal environment adjustment and device optimization design.

       

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