聚光反射器的计算机程序设计

设计了几种聚光反射器.用计算机编写程序进行拟合计算,得出不同反射器的最佳形式、集热器的最佳位置关系和各形状单个反射器的面积;分析比较了各最佳形状反射器的聚光效果,其接收能量比无聚光集热器增加了1倍.     

聚光反射器的实验研究

通过模拟优化计算,制作出4种聚光反射器,并进行了真空管空晒测试.把空晒温度及其变化趋势与当天太阳辐射条件的模拟结果进行了比较,新设计的几种非跟踪聚光反射器的集热效果都颇为理想,可应用于低温蒸汽发电、制冷空调和海水淡化等.     

太阳能电池聚光器的模拟优化

设计了三种槽式太阳能电池聚光反射器模型：梯形、圆弧形和抛物线形,在光学软件Fred中建立模型,利用软件提供的光线跟踪方法,针对其有、无跟踪太阳两种情况进行优化,得出了在这两种情况下,不同几何聚集比（C=1．5,2,2．5,3,3．5）时的最佳形状参数（倾角θ或高底比Hd）,为实际生产加工过程提供了指导,最后对比了三种聚光反射结构的优缺点。     

浸管式加热装置的数值模拟及应用

针对浸管式加热装置设计中普遍存在的热平衡计算复杂、致使设计的加热装置耗能大、热效率低或加热功率达不到生产要求等问题,利用相关的物性参数和经典的燃烧学、传热学公式,编写了用于浸管式加热装置设计的计算机模拟程序。实践表明:程序模拟的结果与实测结果较为吻合。模拟程序的使用可以方便准确地进行设计方案的比选。     

一种非跟踪型太阳能复合聚光器的设计与实验研究

设计一种非跟踪型光电光热复合管以同时得到电能和热能,利用Matlab对聚光器曲线的形状进行优化并对结果进行数值仿真,对不同吸收体形状之间进行数据比较,得到最佳吸收体形状。给出不同入射角的光路图和下表面聚光比分布图,证明下表面得光也较均匀,可避免因高温热应力对太阳电池产生的损坏。最后实验测试下表面平均聚光比,与仿真的结果较为吻合。最后得出下表面三角形腰长为14.5 mm时最为合适并给出设计图。     

塔式太阳能聚光系统与受光器的几何特性

本文分析了采用圆形镜面场的塔式太阳能聚光系统的聚光特性。特别考虑了(1)镜面场中反射镜互相遮挡对收集能量的影响;(2)反射光束总发散角对反射镜映象尺寸大小的影响。给出圆柱形、圆盘形、截锥形和球形受光器的几何特性、平均辐射强度和平均几何聚光比的计算式。对不同的受光器几何形状的聚光特性进行了比较,指出各自的适用场合。     

应用于聚光发电的复合抛物面聚光系统性能仿真研究

构造了一种新型可应用于太阳能聚光发电的复合抛物面聚光器,根据实际尺寸在SolidWorks软件中建模,利用光学分析软件对其进行了光线追迹分析;研究了随入射偏角的变化,太阳电池接受体上接收入射光的变化情况;通过仿真计算模拟,直观地看到了光束在太阳能电池上所形成的焦斑形状、位置和能量分布随入射偏角的变化趋势。模拟计算结果表明,聚光器有效聚光比约为2.61,在测试范围内随着入射偏角增大太阳能电池表面聚焦光斑强度分布渐趋均匀,结论可为槽式太阳能聚光光伏发电的设计和优化提供参考。     

内燃机活塞结构最优化设计

本文提出了一个活塞结构优化设计的数学模型,阐述了对活塞结构进行最优化设计的方法及程序设计问题。在活塞结构优化设计方法中,采用有限元法对活塞进行结构分析和温度场计算。最优化的目标函数取为活塞重量和疲劳敏感系数的加权平均值,设计变量为反映活塞结构形状的几何参数,并把对活塞的变形、温度、疲劳安全系数和重量等的必要限定作为约束条件。另外,对内腔形状的描述采用分段二次函数。活塞优化问题的求解采用复合形法。这种方法,可在电子计算机上进行活塞结构的自动设计,从而获得一个满足各种复杂设计要求的最佳活塞结构方案。文中还以95型柴油机活塞为例,按所提出的方法,对其进行了最优化设计,并分析了计算结果,以说明这种方法的应用性。     

线性菲涅耳集热器接收器对镜场的遮挡研究

带有二次反射器的线性菲涅耳聚光集热器,虽然其接收器表面的能量分布更均匀,但也增加了接收器对反射镜场的遮挡。本文采用理论计算和模拟两种方式对已设计的线性菲涅耳集热器二次反射器对镜场的遮挡情况进行分析,先通过理论计算得出二次反射器对西边三块初级反射镜遮挡角θni的范围,然后利用光线追踪软件模拟出安装和不安装二次反射器两种情况下到达初级反射镜的光线数目,根据光线数目变化情况得出西边三块反射镜的遮挡角变化范围分别为70º ~ 90º、54º ~ 72º和42º ~ 58º,同时引入光线损失率来衡量二次反射镜对镜元遮挡的影响,结果得出安装二次反射器后镜元光线损失率最大值达到23.53%。     

微机版内燃机缸内多维气流运动模拟程序 SUN-Ⅰ 的开发

本文介绍了作者开发研制的微机版内燃机缸内多维气流运动模拟程序ＳＵＮ－Ⅰ的数学模型及程序的结构，探讨了开发微机用大型模拟程序所出现的问题及解决的途径和方法，采用作者开发的计算程序，对柴油机缸内气流运动进行了具体模拟计算，并与在ＣＲＡＹ巨型机上用ＫＩＶＡ－Ⅱ程序的计算结果进行了对比，结果表明，作者开发的微机用模拟程序ＳＵＮ－Ⅰ，已基本实现了ＫＩＶＡ－Ⅱ的功能，其计算精度及使用方便性与ＫＩＶＡ－Ⅱ程序基本相同。     

充流管道单向流固耦合数值模拟自动化研究

针对充流管道单向流固耦合数值模拟过程复杂、数据在耦合传递中存在偏差的问题,采用C＋＋语言编制了充流管道单向流固耦合数值模拟程序,实现了从模型建立、流体计算到结构分析过程的自动化,确保了从流体计算到结构计算过程中数据传递的准确性．利用参考文献中的试验数据验证了此程序计算结果的正确性,以实际发电厂的一段疏水管道为例进行单向流固耦合数值模拟,描述了程序自动建立管道模型、模拟管内流体压力分布以及将流体压力数据导入管道结构中进行管道应力计算的过程．结果表明：该充流管道单向流固耦合数值模拟程序具有结果准确、操作简便的特点,可应用于多种充流管道的设计改造和风险预测中．     

Approximate expressions of maximum value of stress intensity factor of nozzle corner cracks

Based on the flat plate-nozzle model loaded by uniform uniaxial tension, through some suitable reduction and approximation, the maximum value of stress intensity factor (K_I)_max along a crack front can be expressed by the weight function method for the flat plate-nozzle that is loaded by the uniform uniaxial tension and cylinder-nozzle loaded by internal pressure separately. This approach can be valuable for the prediction of fatigue life and failure analysis of pressure vessels. The results so calculated are compared with those reported in the literature and from experiments here reported; and they show good agreement, the discrepancies being less than 15%. This shows that the approximate expressions are effective and can be used in practice.     

A mathematical model for determining the optimal reflector position of a double exposure flat-plate solar collector

A double exposure, flat-plate solar collector (DEFPC) can absorb solar irradiation from both its upper and lower absorber surfaces (LAS). Absorption from the LAS is accomplished using a flat-plate reflector placed below and parallel to the collector. This paper presents a mathematical model for determining the optimum reflector position of the DEFPC in the condition where the LAS is fully irradiated. Compared to other models, this model enables the calculation of the instantaneously irradiated area of the LAS for arbitrary finite dimensions of the reflector and the collector, their arbitrary mutual positions and at any position of the sun in the sky. The optimum reflector positions were obtained by simulating the model in FORTRAN for the spring (autumn) equinox and the winter and summer solstices. The simulations were performed for the optimal yearly position of the collector at 44° N Latitude (Kragujevac, Serbia) and for equal dimensions of the collector and the reflector whose minimum dimensions allow the full irradiation of the LAS. The model was experimentally verified, and the range of the reflector movement during a single year, as well as the optimal reflector dimensions for minimum movement, was determined.     

Approximate expression of the maximum value of the stress intensity factor (SIF) of oblique nozzle corner cracks

In this paper the maximum value of SIF along a crack front can be expressed by the weight function method for a flat plate model with a circular hole loaded in uniform biaxial tension after some suitable reduction and approximation. After considering several factors. ((1) the crack surface loaded by internal pressure; (2) the influence of circumferential stress for the nozzle; (3) the influence of the shape of the opening) and after introducing an oblique angle correction factor, a curvature correction factor and the front free face correction factor, the approximate expressions of maximum value of SIF of oblique nozzle corner cracks are obtained. Comparing the results of these approximate expressions with those in the literature shows good agreement, the discrepancies being less than 13%. This shows the effectiveness of these approximate expressions.     

Electrical and thermal characterization of a PV-CPC hybrid

Long term evaluation of an asymmetric CPC PV-thermal hybrid built for high latitudes, MaReCo (MaximumReflectorCollector), is performed in Lund, lat 55.7°, and this paper discusses output estimates and characteristics of the system. The output estimates are calculated using the MINSUN simulation program. To get the input for MINSUN, measurements were performed on two MaReCo prototypes. These measurements show that the front reflector collects most of the irradiation in the summer, and the back reflector in the spring and fall. Two different reflector materials were used, anodized aluminium and aluminium laminated steel. The steel based reflector was selected for its rigidness. The output estimates show no difference in yearly output between the two reflector materials, both back reflectors deliver 168 kW h/(m² cell area) of electricity compared to 136 kW h/m² cell area for cells without reflectors. The cells facing the front reflector deliver 205 kW h/(m² cell area) of electricity. The estimated output of thermal energy was 145 kW h/(m² glazed area) at 50 °C. The estimates show that the optimal placement of the photovoltaic cells is facing the front reflector, but having cells on both sides is in most cases the best option.     

反光板对提高热管真空管热性能的研究

提出了对带反光板的吸热体接收太阳辐射量的分析方法，并对三种有渐开线反光板且吸热体形状不同的热管真空管和一种无反光板的热管真空管进行了对比实验。结果表明：渐开线反光板可大幅度提高热管真空管的热性能，而且其吸热体的形状对热性能提高的幅度有影响。     

基于CAD/CAE/CAM技术的曲柄连杆机构设计方法研究

探讨了基于CAD/CAE/CAM技术进行曲柄连杆机构设计的方法及其实现过程。首先进行实体建模和虚拟装配,得到曲轴连杆机构的分析模型;然后利用所建模型进行运动学和动力学仿真,并用动力学仿真得到的数据对连杆进行有限元分析;最后对连杆本体进行模拟加工。研究结果表明,在曲柄连杆机构设计中引入CAD/CAE/CAM技术可以大大缩短产品开发周期和节约开发费用。