基于CFD技术的日光温室自然通风热环境模拟

首先利用计算流体力学（CFD）软件，构建自然通风条件下日光温室内温度和气流场的模拟模型；其次，通过测量典型晴天前覆盖下通风口开启时日光温室内各测点的温度，将16个测点的实测值与模型模拟结果进行对比，对模型进行验证；然后，利用通过验证的模型模拟分析3种通风模式下（前覆盖上通风口单独开启、前覆盖下通风口单独开启以及上下通风口同时开启）日光温室内温度和气流场的分布。模拟结果表明：当温室前覆盖上通风口单独开启时，室外冷空气从通风口下端进入并迅速下行，然后通过通风口上端流出，温室内气流主要受热压的影响，空气流速小。当温室前覆盖下通风口单独开启时，温室内0.5m高度以下气流速度较大，室外冷空气从通风口下端进入，与地面、后墙、后坡和覆盖层进行热交换后，从通风口上端流出，温室内温度分布与气流走向一致。当温室前覆盖上、下通风口同时开启时，冷空气从下通风口进入，从上通风口流出，在通风口处气流速度较大。模拟条件下，温室单开上通风口或下通风口时室内平均温度为300.0K，但单开上通风口温室内温度分布更均匀；上、下通风口同时开启时，温室内温度为299.0K，通风降温效果明显优于单开一个通风口。

Simulation Performance of a Ventilated Greenhouse Based on CFD Technology

Simulation model of the airflow and temperature in a naturally ventilated Chinese solar greenhouse was established by using a computational fluid dynamics （CFD） software. The model was tested by comparing observed data and simulated data. The distribution of temperature and airflow inside greenhouse was analyzed through the validated two-dimensional CFD model. The results showed that， when the top vent opened， the cold air outside went into the greenhouse from the lower of vent and went out from the upper of the vent. The airflow in greenhouse was relative low， as mainly affected by heat pressure. When the bottom vent opened， the cold air outside went into the greenhouse from the lower of vent and went out from the upper of the vent， and the airflow below the height of 0.5m in greenhouse was stronger. The distribution of temperature and airflow was similar. When both top and bottom vents opened， the cold air went into greenhouse from bottom vent and went out from top vent， and the airflow at vent was strongest. When only one vent （top or bottom） opened， the average temperature in the greenhouse was 300.0K， however the temperature inside was more even when the top vent opened. When both vents of top and bottom opened， the average temperature in the greenhouse was 299.0K， which was better for temperature decreasing than only one bent opening．