基于VB的风力机叶片外形优化设计

为了实现风力发电机风轮叶片外形的优化设计,以风场风速分布为基础提出了综合优化目标;以片条理论为基础提出了以展弦比为关键参数的修形约束条件的气动优化目标,建立了叶片外形优化设计的数学模型.采用枚举法和循环结构,选用Access数据库,应用Visual Basic编制程序实现叶片外形的优化设计.针对内蒙古某地区设计了1.5MW风力机叶片,与国外同功率某通用叶片进行了对比分析.结果表明,两种叶片外形基本吻合,而且文中设计的叶片在性能上有明显优势,同时也验证了文中提出数学模型的可靠性和程序的实用性.     

基于VB的风力机叶片外形优化设计

为了实现风力发电机风轮叶片外形的优化设计,以风场风速分布为基础提出了综合优化目标;以片条理论为基础提出了以展弦比为关键参数的修形约束条件的气动优化目标,建立了叶片外形优化设计的数学模型。采用枚举法和循环结构,选用Access数据库,应用Visual Basic编制程序实现叶片外形的优化设计。针对内蒙古某地区设计了1.5MW风力机叶片,与国外同功率某通用叶片进行了对比分析。结果表明,两种叶片外形基本吻合,而且文中设计的叶片在性能上有明显优势,同时也验证了文中提出数学模型的可靠性和程序的实用性。     

变壁厚涡轮叶片参数化设计

提出管道交线投影法的中弧线算法,通过圆形管道创建、管道求交和交线投影来计算中弧线.基于中弧线提出涡轮叶片变壁厚算法,通过定义每条截面线上壁厚标志点处的壁厚参数来定义壁厚,将壁厚设计变量从数十个减少至6个,便于参数化设计和优化设计;根据壁厚定义公式,可以设计工程中常见的4种壁厚分布的叶片.最后开发了变壁厚涡轮叶片参数化设计系统,给出设计实例.     

电网故障计算通用程序设计

通过引入虚拟支路和虚拟节点,建立了虚拟故障端口.以虚拟故障端口为边界,将故障电网划分为对称网络和不对称网络两部分,给出了电网故障计算的通用方法.基于此方法,运用Visual Basic6.0,设计开发了一个电网故障计算的通用程序.此程序具有良好的人机界面,计算速度快、计算结果准确.文中最后以某电网为例进行了计算,其结果验证了程序的有效性.     

基于MATLABGUIDE的电力系统潮流计算

潮流计算是电力系统分析中最基本和最重要的一种计算。对电力系统的数学建模以牛顿-拉夫逊法为基础,通过改进雅可比矩阵的分块方式以利于计算机编程。以MATLAB开发潮流算法程序,利用MATLAB内置的可视化编程工具GUIDE开发潮流计算程序界面,并给出了相关实例。     

大型水平轴风力机叶片气动性能优化

为提高风力机将风能转化为机械能的效率,根据我国西北地区的风频风能曲线,用最优设计攻角沿叶片轴线的非线性分布修正传统Wilson算法,优化设计大型水平轴风力机叶片的气动性能. 该优化设计利用Matlab优化工具箱,优化速度干涉因子的迭代计算,提高计算效率;考虑多翼型和变攻角等因素对叶片外形优化的影响,从结构及加工工艺角度修正翼型. 通过对1.2 MW 风力发电机组叶片外形的气动性能计算和优化设计,结果表明该优化设计的有效性和可行性,可为风力机叶片外形设计提供参考.     

单端正激变换器的优化设计

本文以两路输出变换器的变压器为侧,介绍了单端正激直流-直流变换器的优化设计方法,为了在满足性能指标约束下,求变压器功耗和重量加权和的极小值,根据理想波形和理论公式推导了数学模型,本文应用增广拉格朗日乘子罚函数法,编制了CAD程序(FORTRAN IV),文中给出了计算机计算结果、重量一损耗曲线,并对优化设计结果进行了讨论。     

卫星光压分析模块的实现

卫星光压分析对于卫星总体设计和姿态控制设计是非常重要的.为提高光压计算的通用性、提高计算效率,给出了一种通用的光压计算方法,开发了光压计算程序.详细讨论了光压计算及其程序开发的理论基础、设计思想,定义了光压计算的计算机分析流程.针对几何表面模型表达,遮挡判断、结果分析等方面进行了阐述,给出了包围球判断、细划面元、地影判断等方法.最后完成了光压分析程序代码编制,给出了实例与分析.     

基于参数化的涡轮叶片三维气动优化仿真

为了提高涡轮叶片的设计效率,在分析已有涡轮叶片截面线参数化造型技术优缺点的基础上,基于B样条曲线实现了涡轮叶片截面线的参数化造型和参数化修改,并编写了叶片造型程序,实现了叶片流场模型的自动化生成.以某型号涡轮叶片为例,对其进行三维流场数值模拟,然后采用遗传算法和序列二次规划法算法的组合,以涡轮的气动效率为目标函数,对涡轮叶片进行了气动优化.算例结果表明文中所建立的涡轮叶片自动优化设计体系是可行的.     

基于栅格GIS土壤侵蚀地形因子的提取算法

论述了基于栅格GIS土壤侵蚀地形因子的计算方法和流程，在ARCGIS栅格模块中利用AML开发了通用土壤流失方程地形因子的计算程序，并给出了程序核心部分的编码。实际应用表明，计算结果的精度依赖于数据源的精度。     

采用JAVA RMI实现自动并行计算的叶型优化设计平台

论文采用JAVARMI技术,把已有的分区处理的并行分析计算程序变成自动化的、支持异构网络环境和操作系统的全三维叶型设计平台。该平台的特点是采用了高精度、超快速的全三维粘性流动的求解程序,并且使这个过程自动化,从而能够对多个叶型方案进行比较,迅速得到改进叶型。结果证明,采用4分区结构,用这个系统对一个叶片进行设计优化,使得到新结果的速度提升了接近4倍。     

Sensitivity analysis of artificial neural networks for just-suspension speed prediction in solid-liquid mixing systems: Performance comparison of MLPNN and RBFNN

Just-suspension speed (Njs) is an important parameter for stirred tank design using a solid-liquid mixing system in the chemical process industry. However, current correlations for Njs suffer from uncertainty from limited experimental databases and limitations due to many parameters that play an important role in Njs determination. A comprehensive computation of the radial basis function neural network (RBFNN) was developed based on solid-liquid mixing experiments, which contain 935 datasets for the prediction of Njs. The Njs values were obtained experimentally using Zwietering correlation with different solid loading percentages, solid particle density, solid particle diameter, mixing solvent density, number of impeller blades, impeller diameter, impeller blade hub angle, impeller blade tip angle, the width of the impeller blade and the ratio of the clearance between the impeller and the bottom of the tank with the tank diameter. The RBFNN proved to have a much better ability to accurately predict the desired Njs compared to MLPNN even after decreasing the number of input variables from 11 to 8. Thus, the computational RBFNN model results will be useful for extending the application of a solid-liquid mixing system for estimating the just-suspension speed for stirred tank design.     

Interactive computer programme to facilitate diesel engine/propeller matching

The general problem of matching a diesel engine to a propeller is solved using a computer programme. The programme can deal with any engine specified by constraints on its power speed characteristic readily available from manufacturers, and any hull form provided resistance vs speed curves are available either from scale model experiments, standard curves or sea trials. For any selected propeller diameter, gear ratio or propeller blade area ratio the programme automatically calculates the maximum ship speed which just satisfies the engine constraints over a range of propeller pitch ratio values. The calculation is based on using a data bank of previously. stored model series thrust and torque parameters, and the resulting forward speed vs pitch ratio curve is presented on a graphics terminal. Families of these characteristics can be automatically generated for selected variations in propeller diameter, blade area ratio, gear ratio or for different resistance vs speed curves which may represent other ship displacements, trims or account for fouling, weather, etc. The display curves are stored and may be interactively retrieved under light pen control so that rapid comparisons can easily be drawn between different parameter selections.As an example of the use of the programme the paper describes the design of a propulsion system for a small commercial vessel using hypothetical data, and thus demonstrates the sensitivity of speed vs pitch ratio characteristic variations with propeller diameter, gear ratio, blade area ratio and displacement, and some general conclusions may be drawn from the results presented.     

平流双效精馏过程的模拟和优化

对平流双效精馏过程进行了详细研究，建立了最优化设计的数学模型并编制了通用计算机最优化设计程序，用实例对所建立的数学模型及优化设计方法进行了考核计算，发现平流双效精馏节能效果显著，具有很高的应用价值。     

涡轮气冷叶片传热分析数据提取技术研究

涡轮气冷叶片传热管网计算是涡轮气冷叶片传热设计的重要环节,针对涡轮气冷 叶片传热设计需求,提出了涡轮气冷叶片模型传热分析数据提取的方法,具体包括计算单元划 分、流路自动判断、网络图生成和传热数据提取等算法。结合涡轮气冷叶片结构特点,使用UG Open API 工具开发了传热分析数据提取系统,实现了涡轮气冷叶片传热分析数据的提取、管理 和输出功能,以用于后续的分析计算,提高了传热设计管网计算的自动化水平,并通过实例验 证了所提出方法的可行性。     

Hierarchical optimization of the composite blade of a stratospheric airship propeller based on genetic algorithm

High-altitude propellers equipped with solar energy systems are widely adopted in stratospheric airships because of their light weight, excellent mechanical performance, and high efficiency. To optimize the composite laminated structure of the blade, a hierarchical optimization method based on genetic algorithm is carried out. Global and local layers are combined according to the structural and loading properties of the blade, and each partitioned region in the local layer is optimized independently. Combined with the finite element method, a subprogram based on the classical lamination theory is developed to simulate the stiffness matrix of the blade and obtain the deflection, weight, etc. as objects. The restricted condition, whether the structure has failed, is determined by the Tsai-Wu criterion. In addition, multiple tasks are delivered and read simultaneously by a specific program for the sake of improving computation efficiency. After verification with a case study, the stacking sequence and thickness of the blade of a stratospheric airship propeller is optimized and an ideal result is obtained.     

Torsional Vibrations of Pre-Twisted Blades using Artificial Neural Network Technology

The free torsional vibrations of a linearly tapered, twisted flexible blade, rotationally constrained at an arbitrary position along the length of blade, have been investigated using neural networks. The blade has a rectangular cross-section with equal taper in the horizontal and vertical planes, in addition to the flexibility at the root portion. The constraint is a rotational spring. The constraint on the blade at an optimum location is designed so as to increase the lowest natural frequency of the blades with considerable root flexibility. The optimum location is determined as the position of the node in the second mode shape of the unconstrained tapered blade with flexible roots. A trained neural network is used to identify the location of the nodal or optimum point for a given blade–taper ratio and root flexibility parameter. The minimum stiffness of the constraint at an optimum position for a maximum raise in the first eigenfrequency is evaluated. Results are presented in tabular and graphical form.     

压气机叶片扭曲规律的多目标三维气动优化

为了提高轴流压气机的等熵效率和总压比,采用基于人工神经网络及遗传算法的叶轮机械叶片三维优化设计方法,开发了一种高性能的动叶片。优化目标是在流量不减小的情况下,尽可能的提高转子叶片的总压比和等熵效率。优化仿真结果显示,优化后所获得的扭曲叶片可以有效地改善叶根处的流动分离,流动分离区明显后移,损失显著降低,在整个工作范围,等熵效率提高了1.27%-7.08%,流量和总压比也都得到了大幅度的提高。结果表明,对亚音叶片进行扭曲规律优化效果很明显,优化方法是获得高性能转子叶片的有效途径。