一种导流型太阳能热气流系统流动与传热特性的实验研究

Experimental Study on Flow and Heat Transfer Characteristics of Adiversion-type Solar Chimney

搭建了一座小型的导流型太阳能热气流系统实验台,利用相关实验仪器所测数据对其进行流动与传热特性的实验研究。研究结果表明:实验台内的气流温度及速度的变化会受到环境因素的影响,太阳辐射强度的强弱会直接影响集热器内的气流温度分布以及导流塔底部的气流速度分布;环境风速对气流温度和速度也有一定的影响。集热器内气流温度的分布沿着入口向出口处逐渐升高,导流塔底部的气流温度最高,且南侧温度普遍高于北侧温度;当环境风速较低(0.36、0.41 m·s^(-1))时集热器内的气流温度提高率较高,而当环境风速较高(0.61 m·s^(-1))时集热器内的气流温度提高率下降。导流塔底部气流速度集中分布在不同区间范围,整体分布呈正态分布,集中在0.6~1.2 m·s^(-1)气流。太阳辐射强度越强导流塔底部的气流速度也越高;环境风速低,则导流塔底部的气流速度在较低速度出现的频率高,而环境风速较高,则导流塔底部的气流速度在较高速度的范围出现的频率高。

A miniature diversion-type solar chimney was built and the flow in the experimental appratus and heat transfer characteristics of the airflow were studied by using relevant experimental data.The results show that the variation of temperature and velocity of the airflow in the experimental platform will be affected by environmental factors,the intensity of solar radiation directly affect the temperature distribution under the heat collector and the velocity distribution of the airflow at the bottom of the diversion tower;the ambient wind speed also has certain effects on the temperature and velocity distribution of the airflow.The temperature distribution under the collector gradually rises along the inlet to the outlet,the temperature at the bottom of the diversion tower is the highest,and the temperature of the south side is generally higher than the north.The temperature improvement rate under the collector is higher when the ambient wind speed is 0.36 or 0.41 m·s^(-1),while it decreases when the ambient wind speed is 0.61 m·s^(-1).The bottom airflow velocity of the diversion tower is concentrated in the different interval range,and the overall distribution is normal,concentrated in the interval range of 0.6—1.2 m·s^(-1).The stronger the solar radiation intensity,the higher the velocity of the airflow range at the base of the diversion tower;with low ambient wind speed,the velocity of the airflow at the bottom of the diversion tower appears more frequently in the range of lower velocities;while with higher ambient wind speed,the velocity of the airflow at the bottom of the diversion tower appears higher in the range of higher velocities.