有石英窗口的圆柱形腔体热损失特性实验研究

Experimental Investigation on Heat Loss Characteristics of Cylindrical Cavity With Quartz Window

腔体热损失特性是太阳能热发电领域的研究热点之一。石英窗口能使腔体内部与周围空气分离,改变腔体气流模式和温度分布,减小对流和辐射热损失,因此本文对有石英窗口的圆柱形腔体热损失特性进行实验研究。结果表明:石英窗口显著提高了腔体壁面温度。改变倾角和加热方式对侧壁面温度分布影响较大,底面温度基本保持稳定。腔体开口向上时,Nur、Nuc无明显变化;开口向下时,Nur随倾角变化很小,而Nuc变化较大。改变加热方式会引起Nur和Nuc的明显变化,尤其在单独底面加热且倾角接近90°时,Nuc迅速增加。

The cavity heat loss characteristic is one of the research hotspots in solar thermal power generation.The quartz window can separate the interior of the cavity from the surrounding air,change the airflow pattern and temperature distribution of the cavity,and reduce the convection and radiation heat loss.In the present work,the heat loss characteristics of the cylindrical cavity with a quartz window are studied experimentally.The results show that the quartz window significantly increases the cavity wall temperature.Changing the tilt angle and heating method has great influence on the temperature distribution of the side wall surface,while the bottom surface temperature remains stable.When the cavity opening is upward,there is no significant change in Nur and Nuc;when the opening is downward,Nur changes little with the tilt angle,but Nuc changes greatly.Changing the heating method will cause significant changes in Nur and Nuc,especially when the bottom surface is heated alone and the tilt angle is close to 90°,at which Nuc increases rapidly.