高次柱面反射型太阳能聚光镜的光学设计

Optical design of a reflective concentrator mirror utilizing higher order cylindrical surfaces

提出了一种新型高效太阳能聚光镜,这种聚光镜用一组特定系数,a2,a4,a6,a8,a10,a12,a14,a16与C的高次柱面内壁的一部分作为反射镜.利用高次柱面方程和光反射定律,推导出了在高次柱面内壁上太阳反射光束的方向矢量与高次柱面系数C,a2,a4,a6,a8,a10,a12,a14,a16的关系,通过优化设计这些系数,可以使入射到高次柱面内壁上的太阳光束反射后全部聚焦在一条与柱面母线平行的宽度很窄的线段上,形成线聚光.这组特定系数用粒子群优化算法求得,并经计算机模拟证明其聚焦效果.用这组特定系数的高次柱面作为聚光镜,其对光的压缩比可达148倍,其线性光斑可作为一种强光源或高温光源.高次柱面反射镜可由金属或玻璃直接磨制而成,也可由高次柱面骨架和铺设在骨架上的镀铝聚酯薄膜构成.

In this paper,we present a new and highly efficient solar concentrating mirror.It is composed of partial high-order cylinder inner wall which is determined by two sets of specific coefficients a2,a4,a6,a8,a10,a12,a14,a16 and C.According to the higher-order cylindrical equation and the optical law of reflection,the relationship between the direction vectors of sunbeams reflected from the cylindrical inner wall and the coefficients of a higher order polynomial equation,a2,a4,a6,a8,a10,a12,a14,a16 and C is derived.By optimizing these coefficients,all sunbeams incident on the inner wall of higher-order cylinder can be reflected and focused into a very thin line segment parallel to the cylindrical busbar,which means line focus.Two sets of particular coefficients associated with the highorder cylindrical surface are obtained by using particle swarm optimization algorithm.The focusing effect of the solar concentrating mirror,defined by the particular set of coefficients,is demonstrated by using computer simulations.The concentrator mirror has a light compression ratio of about 148：1 and its linear spot can be used as a strong light source or a high temperature heat source.The higher-order cylindrical mirror can be made of metal or glass in three steps：cutting,grinding,and polishing,and may also be formed by a higher order cylindrical framework and an aluminized polyester film laid on the framework.