日光温室土壤-空气换热器周围土壤中热湿迁移规律研究

Study on the Heat and Moisture Transfer Principles of Soil Fields Surrounding the Soil-Air Heat Exchanger in Solar Greenhouse

为研究日光温室土壤-空气换热系统土壤中的热湿耦合迁移规律,建立了水平换热管周围非饱和土壤中热湿耦合传递的数学模型,模拟非饱和土壤蓄热过程中温湿度的动态分布。结果表明,温湿度场的分布密切相关。在土壤中温度梯度作用下,土壤中的湿分沿温度梯度反方向迁移,且依次形成湿峰。各向同性土壤中,距管中心距离相同的各点,同时出现湿峰。管内空气温度越高,湿度峰值越明显。利用土壤-空气换热器对高温空气进行降温,含湿土壤中的传热传质,有利于换热系统获得较低的空气出口温度。

To investigate the heat and moisture transfer principles of the soil fields surrounding the soil-air heat exchanger in solar greenhouse,a mathmatical modle coupled the heat and moisture transfer in soil fields was built up and used to simulate the dynamic temperature and humidity distributions in soil during the heat storaging procedure. The results show that the moisture distribution was directly effected by the temperature gradient of soil.The moisture in soil was transferred with the reverse direction of the temperature gradient.In homogeneous soil fields,the maximum humidity peak points was appeared at places with the same distances from tube center,and the higher the temperature of air in tube,the more apparent of the humidity peak.Because of the heat and moisture transfer in soil fields,it is feasible to use heat and moisture transfer to greatly reduce the high supplying air temperature.