基于CFD的模块化食用菌工厂气流组织优化与试验

Optimization and Experiment of Airflow Organization in Modular Edible Mushroom Factory Based on CFD

摘要:

针对模块化食用菌工厂中栽培密度高、气流组织不合理及食用菌呼吸代谢产热引起的热聚集问题,本文提出一种耦合生物热源与多孔介质的CFD数值模拟方法,用于食用菌工厂气流组织优化。基于黄伞菌(Pholiotaadiposa)呼吸速率实测数据,构建了包含内生物热源的各向异性多孔介质模型。模型验证结果表明,仿真与实测温度、风速的均方根误差分别为0.32℃和0.08m/s,模型精度可靠。以原工厂模式为对照,对比分析了异侧下进上出、异侧下进中出和异侧下进下出3 种气流循环模式对温度场和流场分布的影响,并以变异系数评价多孔介质区域温度均匀性。结果表明,异侧下进上出模式可有效削弱顶部热滞留,其区域最大温差为1.24℃,平均温度为11.5℃,较原模式分别降低0.46℃和0.24℃,温度变异系数降至1.6%。实际栽培试验表明,在制冷机组启、停工况下,优化方案的温度变异系数分别为1.64%和2.95%,较原模式分别降低0.92、2.85个百分点;风速变异系数降至37.66%,降低2.77个百分点。优化后的气流组织使黄伞菌出菇率和成熟率分别提高0.88、2.80个百分点,为食用菌工厂气流组织设计与环境精准调控提供参考。

Abstract:

Aiming to address heat accumulation in a modular edible mushroom factory caused by high cultivation density, unreasonable airflow organization, and mushroom respiratory heat production, a CFD-based numerical method coupling biological heat sources with porous media was proposed for airflow optimization. Based on the measured respiration rate of Pholiota adiposa, an anisotropic porous-medium model with internal heat sources was established. The root mean square errors between simulated and measured temperature and air velocity were 0.32℃ and 0.08m/s, respectively, indicating good model accuracy. Using the original factory configuration as the control, three airflow organization modes were compared, and the coefficient of variation was used to evaluate temperature uniformity in the porous-medium region. Results showed that the opposite-side bottom-supply and top-return mode effectively reduced heat retention at the top, with a maximum temperature difference of 1.24℃, an average temperature of 11.5℃, and a temperature coefficient of variation of 1.6%, which were reduced by 0.46℃, 0.24℃, and 1.9 percentage points, respectively, compared with those of the original mode. Cultivation experiments further showed that, under cooling-on and cooling-off conditions, the temperature coefficients of variation of the optimized scheme were 1.64% and 2.95%, respectively, which were reduced by 0.92 and 2.85 percentage points, respectively, compared with those of the original mode, while the air velocity coefficient of variation was decreased to 37.66%, a reduction of 2.77 percentage points. The fruiting rate and maturity rate of Pholiota adiposa were increased by 0.88 and 2.80 percentage points, respectively. The results can provide a reference for airflow design and precise environmental control in edible mushroom factories.