Abstract We report on the effectiveness of an air curtain to mitigate convective heat losses from a heated cylindrical cavity receiver operated at fixed tilt (15°) and yaw angles (0°). The cavity was heated electrically with a controller to maintain a constant inside temperature of 300 °C, varying wind speed, air curtain velocity and discharge angle. It was found that the greatest convective heat losses occur over the lower internal surfaces of the cavity for all cases, spanning both natural and forced convection regimes, while a discharge angle of 30° relative to the face of the cavity is more effective than a parallel curtain, which was found to increase heat losses. It was also found that, for a discharge angle of 0°, increasing the velocity of the air curtain leads to higher convective heat losses. However, for a curtain discharge angle of 30°, increasing the air curtain velocity can reduce heat losses by up to 60%. The measured distribution of air temperature across the aperture plane and convective heat losses through the surface were used to provide insight into the causes of these observations. These results suggest that, for tilted, tower-mounted cavity receivers, the orientation of an air curtain should be directed with a component towards the wind, rather than parallel to the aperture plane.

中文翻译：

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对配备气幕的圆柱形太阳能腔接收器热损失机制的实验见解

摘要我们报告了空气幕在减轻以固定倾斜 (15°) 和偏航角 (0°) 运行的加热圆柱形腔体接收器的对流热损失方面的有效性。腔体通过控制器进行电加热，以保持 300°C 的恒定内部温度，改变风速、空气幕速度和排放角。发现在所有情况下，最大的对流热损失发生在空腔的下部内表面，跨越自然对流和强制对流状态，而相对于空腔表面的 30° 排放角比平行对流更有效。窗帘，这被发现会增加热损失。还发现，对于 0° 的排放角，增加空气幕的速度会导致更高的对流热损失。但是，对于 30° 的帘式排放角，增加气幕速度可以减少高达 60% 的热损失。测量的穿过孔平面的空气温度分布和穿过表面的对流热损失用于深入了解这些观察结果的原因。这些结果表明，对于倾斜的、安装在塔上的空腔接收器，气幕的方向应该指向风，而不是平行于孔径平面。