利用光学凹型透镜中功能曲面对太阳光线传输的重新分配能力,提出在腔体接收器前端安装凹型石英窗(凹透镜)以改善能流均匀性。为此,采用一种联合光线跟踪方法和遗传算法的优化设计方法优化凹透镜的几何尺寸和安装位置,改善碟式系统的能流均匀性。对于4种典型的二次曲面和三种曲面布置方式组合的12种凹透镜,详细分析凹透镜改善碟式系统能流均匀性的有益效果和特点,并验证所提方法的有效性。结果表明,在碟式系统中增加优化的凹透镜不仅能够显著改善腔体接收器的能流均匀性以及降低局部能流的峰值,还能够获得优异的光学效率和直接有用能率,优化的双圆锥透镜可将非均匀因子从0.59显著减小到0.11。

A concave quartz window (concave lens) is installed at the front end of a cavity receiver to improve the uniformity of energy flow and gain advantage of the redistribution ability of the functional curved surface of an optical concave lens to the transmission of solar light. A combined ray-tracing method and genetic algorithm optimization design method are used to optimize the geometric size and installation position of the concave lens and improve the uniformity of the energy flow of the dish system. Twelve types of concave lenses are combined with four distinct quadric surfaces and three curved surfaces. The benefits and characteristics of concave lenses in improving the uniformity of energy flow of the dish system are analyzed in detail, and the effectiveness of the proposed method is verified. The results show that adding an optimized concave lens to the dish system can significantly improve the energy flow uniformity of the cavity receiver, reduce the local energy flow peak, and obtain excellent optical and energy efficiency. The optimized double cone lens showes a significant reduction of the non-uniformity factor from 0.59 to 0.11.