An optimized Monte Carlo ray tracing optical simulation model and its applications to line-focus concentrating solar collectors
An optimized Monte Carlo ray tracing optical simulation model and its applications to line-focus concentrating solar collectors
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DOI：
10.1016/j.apenergy.2018.05.067
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发表时间：
2018-09
期刊：
影响因子：
11.2
通讯作者：
Manman Fan;Shijun You;Junbao Xia;Wandong Zheng;Huan Zhang;Hongbo Liang;Xianli Li;Bojia Li
中科院分区：
文献类型：
--
作者：
Manman Fan;Shijun You;Junbao Xia;Wandong Zheng;Huan Zhang;Hongbo Liang;Xianli Li;Bojia Li
蒙特卡罗射线追踪（MCRT）方法在聚光太阳能集热器（CSC）光学模拟中被证明是灵活有效的，但通常需要较高的计算成本和较长的运行时间，或者在多次运行中其结果会出现波动。随机数产生方式、射线数、运行次数、网格数、随机数产生次数等参数对模拟结果都有影响。结果表明，使用较少的光线数多次运行MCRT模型可以减少结果的波动，同时减少总运行时间。以金属玻璃接收器抛物面反射器线聚焦CSC为例，MCRT方法在1 × 108射线运行1次、2 × 107射线运行1次和3 × 106射线运行5次时的最大相对误差（emax）和平均相对误差（eavg）均低于阈值（Emax= 5%，Eavg = 0.5%），但总运行时间分别约为410 s，82 s和63 s。在此基础上，将MCRT方法与迭代方法相结合，提出了一种优化的MCRT模型，其中引入了最小运行时间（tmin）和最大运行时间（tmax），可以方便地改变它们以满足不同光学模拟的要求。将该模型应用于具有更复杂腔体接收器或复合抛物面反射器的线聚焦CSC，总运行时间分别在268-413 s和26-102 min的范围内变化，表明当相对误差的限制可接受时，运行时间的减少是显著的。该模型有利于减小MCRT方法的波动，提高精度，减少运行时间。该方法也可进一步用于各种CSCs的光学模拟。
The Monte Carlo Ray Tracing (MCRT) method has been confirmed flexible and efficient in the optical simulation of Concentrating Solar Collectors (CSCs), but it usually needs higher computing cost and longer runtime or its results fluctuate in multiple runs. The parameters of the way of random number generation, the number of rays, running times, grid numbers, and random number generation times all exerted effects on the simulation results. It was found that running the MCRT model with less number of rays for several more times could mitigate the fluctuation of results and decrease the total runtime simultaneously. Taken the Line-focus CSC with a metal-glass receiver and a parabolic reflector as an example, the maximum (emax) and average (eavg) relative errors of the MCRT method with 1 × 108rays running for once, 2 × 107rays running for once and 3 × 106rays running for five times were all lower than the threshold values (Emax= 5% andEavg= 0.5%), but the total runtime was about 410 s, 82 s and 63 s respectively. On these bases, an optimized MCRT model was proposed by combining the MCRT method with the iteration method, where the minimum running times (tmin) and the maximum running times (tmax) were introduced, and they could be changed conveniently to meet the requirements of different optical simulations. By applying the proposed model to the Line-focus CSC with a more complex cavity receiver or compound parabolic reflector, the total runtime varied in the range of 268–413 s and 26–102 min respectively, indicating that the runtime reduction was significant when the limit of relative errors were acceptable. The proposed model is beneficial to mitigate the fluctuation, improve the accuracy and reduce the runtime of the MCRT method. It can also be further used to the optical simulation of various kinds of CSCs.