日光温室湿度分布的数值模拟

以山西晋中地区日光温室作为研究对象,通过在温室内部布点测量温、湿度的试验和采用CFD进行数值模拟的方法,研究了冬季晴朗天气状况下,采用畦灌方式的日光温室在自然通风条件下内部湿度的分布规律。结果表明,冬季晴朗天气状况下,日光温室在08:00左右湿度达到最高值,14:00左右温度达到最高值;室内温、湿度显著负相关,温度每升高1℃,湿度降低3.31%;温室内部温度实测值与模拟值误差在±3℃以内,湿度实测值与模拟值误差在6.8%以内,整体拟合情况较好,证明了所建立模型的准确性;温室湿度在南北走向、东西走向变化不太明显,垂直方向上分层比较明显。太阳辐射所提供的热量足以维持温室所需,草帘的保温效果显著,无需对温室进行加温,但是温室夜间湿度较高,甚至接近饱和,需要对湿度进行控制。

Numerical Simulation of Temperature and Humidity Distributions in a Solar Greenhouse

This paper simulated numerically the distributions of temperature and humidity in a solar greenhouse in Jinzhong district,Shanxi province under natural ventilation in sunny days,using a CFD-based model.Plant in the greenhouse was irrigated using furrows and the spatio-temporal distributions of temperature and humidity in it were measured.The results showed that during sunny days in winter,the indoor-humidity and temperature in the greenhouse peaked around 08:00 am and 14:00 pm respectively.The indoor-humidity and temperature were negatively correlated,and when the temperature rose by 1 ℃,the humidity decreased by 3.31％.The discrepancy between the measured and simulated temperatures was within ±3 ℃,and the errors of the simulated humidity was less than 6.8％ in comparison with the measurements.The gradients of humidity and temperature in the northsouth direction and the east-west direction were similar,while in the vertical direction the heterogeneous effect was significant.The energy of the solar radiation could meet the demands when the greenhouse was insulated by woven straws,and there was no need to heat the greenhouse.However,the humidity in the greenhouse was relatively high in nights,close to saturation,requiring control.