共查询到19条相似文献,搜索用时 781 毫秒
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槽式太阳能集热器集热性能分析 总被引:4,自引:1,他引:3
本文运用蒙特卡罗光线追踪法(MCRT)模拟了抛物槽式系统聚光特性,并与计算流体与传热有限容积方法(FVM)结合,进一步研究了吸热管内耦合传热过程.聚光特性分析中考察了光不平行夹角、几何聚光比和边界角对太阳热流密度分布的影响;耦合传热模拟中考虑了液体油热物性随温度的变化以及吸收管外管壁辐射换热.模拟计算表明;模拟计算结果与文献数据对比符合较好,验证了计算方法与模拟程序的正确性.光不平行夹角主要对热流密度圆周方向分布产生影响,使其分布平缓,对热流密度轴向分布影响不大;随着几何聚光比的增大,太阳热流衰减区的角度跨度增大;随着边界角的增大,热流密度圆周分布曲线向圆周角90°方向平移,同时热流密度极大值降低.在太阳直射强度大致相同情况下,入口流速与入口温度对接收管表面对流换热与最大温差影响很大;同时变物性对流体对流换热影响也较大. 相似文献
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求解介质内热辐射传递的双向统计蒙特卡罗法 总被引:2,自引:0,他引:2
基于热辐射传输的光路可逆性原理,提出了求解介质内热辐射传递的双向统计蒙特卡罗法(BSMC法)。该方法采用等温等权抽样,利用能束传输路径的可逆关系进行辐射传递的双向统计计算,充分利用了能束跟踪的计算信息。以二维矩形区域内吸收性介质的热辐射传递为例,介绍了BSMC的求解过程,分析了其计算误差。通过数值模拟,从辐射传递因子计算结果的倒易性满足程度与辐射平衡温度场两方面,将BSMC法与传统的蒙特卡罗法(TMC法)进行了比较。结果表明,在相同的计算量下,BSMC法比TMC有更高的模拟精度。 相似文献
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球形微粒子近场辐射换热研究 总被引:1,自引:0,他引:1
从偶极辐射理论出发,结合普朗克黑体辐射分布,推导出近场区热辐射分布。采用MC法模拟了两个纳米球形 村子的辐射换热,考察相天参数对近场辐射换热的影响。表明其辐射热流可比黑体辐射高8个数量级。其热流随间距的增 大急剧减小。小研究对于纳米粒子群的传热研究有积极意义。 相似文献
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Yong Shuai 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(7):1281-1296
Using Monte Carlo method, the paper investigates the radiative heat transfer in participating media. Based on the radiative exchange factor, an uncertainty analysis of Monte Carlo method is undertaken and the corresponding mathematical expressions are deduced to predict its accuracy. Furthermore, randomness properties of pseudorandom number generators are investigated, and a model to test radiation symmetry is adopted to validate the performance of some generators. The paper studies the effects of energy bundle numbers, discretization schemes, emission location, optical thicknesses, wall emissivity and CPU time on the numerical accuracy. In addition, the simulation results are proved to give a reference for using Monte Carlo method, which is applicable for calculation of the radiative exchange factor. 相似文献
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L.H. Liu H.C. Zhang H.P. Tan 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,84(3):357-362
A Monte Carlo discrete curved ray-tracing method is developed to analyze the radiative transfer in one-dimensional absorbing-emitting semitransparent slab with variable spatial refractive index, in which the Monte Carlo method is combined with the discrete curved ray-tracing method. A problem of radiative equilibrium with linear variable spatial refractive index is taken as an example to examine the accuracy of the proposed method. The temperature distributions and the dimensionless radiative heat flux are determined by the proposed method and compared with the data in references, which are obtained by other different methods. The results show that the Monte Carlo discrete curved ray-tracing method has a good accuracy in solving the radiative transfer in one-dimensional semitransparent slab with variable spatial refractive index. 相似文献
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L.H. Liu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,102(2):293-303
In graded index media, the ray goes along a curved path determined by Fermat principle. Generally, the curved ray trajectory in graded index media is a complex implicit function, and the curved ray tracing is very difficult and complex. Only for some special refractive index distributions, the curved ray trajectory can be expressed as a simple explicit function. Two important examples are the layered and the radial graded index distributions. In this paper, the radiative heat transfer problems in two-dimensional square semitransparent with layered and radial graded index distributions are analyzed. After deduction of the ray trajectory, the radiative heat transfer problems are solved by using the Monte Carlo curved ray-tracing method. Some numerical solutions of dimensionless net radiative heat flux and medium temperature are tabulated as the benchmark solutions for the future development of approximation techniques for multi-dimensional radiative heat transfer in graded index media. 相似文献