基于CFD的花卉温室夏季机械通风模拟

Simulation of summer mechanical ventilation in flower greenhouses based on CFD

为了研究实际花卉温室中夏季机械通风温度场和气流场对于花卉作物生长的影响,采用流体力学软件ANSYS FLUENT 19.0对温室进行三维计算流体动力学(CFD)模拟。通过在温室中布置温度测点,分析夏季机械通风模式下的温度分布规律;采用k-ε模型(RNG)对温室室内小气候进行模拟,离散纵坐标(DO)辐射模型进行室内辐射模拟,控制算法采用PISO算法,压力分散采用体积力加权法;设置求解器进行稳态分析,变量残差收敛的标准设为10^(-4)。在试验条件下,计算结果与试验结果吻合较好,模拟速度场误差范围在0.5%~24.6%,模拟温度在实测温度附近波动,RMSE=1.9826,MAE=2.1534,温度模拟值与实际值的绝对误差最大值小于2.5℃。模拟结果表明,夏季机械通风情况下温度场分布较均匀,适合花卉生长。

In order to study the effect of temperature field and airflow field of mechanical ventilation on the growth of flower crops in the actual flower greenhouse in summer,the hydrodynamics software ANSYS FLUENT 19.0 was used to conduct three-dimensional CFD simulation of the greenhouse.Temperature measurement points were arranged in the greenhouse to analyze the distribution of temperature under mechanical ventilation mode in summer;the k-εmodel(RNG)was used to simulate the indoor microclimate of greenhouse,and the discrete ordinate(DO)radiation model was used to simulate the indoor radiation.The control algorithm was PISO algorithm,and the pressure dispersion was adopted by volume force method.The solver was set for steady analysis,and the standard of variable residual convergence was set as 10^(-4).Under the experimental conditions,the calculated results were in good agreement with the experimental results.The error range of the simulated velocity field was 0.5%~34.6%,the simulated temperature fluctuated around the measured temperature,RMSE=1.9826,MAE=2.1534,and the maximum absolute error between the simulated temperature and the actual temperature was less than 2.5℃.The simulation results showed that the distribution of temperature field was more uniform under mechanical ventilation in summer,which was suitable for flower growth.