三通管道优化设计

优化设计是一种寻找最优设计方案或者说是最有效率方案的技术，充分挖掘设计潜力，比较并评价设计方案，给出最优设计。所谓“最优设计”，指的是一种方案可以满足所有设计要求，而且所有的支出（如重量、面积、体积、应力、费用等）最小。也就是说，最优设计方案就是一个最有效的方案。本文简要介绍了有限元设计优化及结构优化的力学准则，并应用大型有限元分析程序ANSYS对三通管道的接管内径与主管道内径之比及壁厚进行了优化，同时对优化变量、优化方法和生个优化过程进行了详细说明，最终得到满足功能和强度要求的最优设计。     

整体翅片叉排热管散热器的传热特性研究

针对三维坐标系下,整体翅片叉排热管散热器的流动和传热特性进行数值模拟研究.分析了四个主要影响因素:翅片间距、翅片厚度、排间距和管排布对努塞尔数、流动摩擦因数和热阻的影响.管排布分别为4-3叉排和3-2叉排,翅片间距分别为6mm、7mm和8mm,翅片厚度分别为0.8mm、1mm和1.2mm,排间距分别为20mm、24mm和28mm.计算结果表明:随着翅片厚度的增加,摩擦因数减小,换热能力增强,热阻有所上升;随着翅片间距的增大,摩擦因数增大,换热能力提高,而热阻基本为增加趋势;当热管排列方式从4-3叉排变为3-2叉排后,摩擦因数增加,但Re较大时,摩擦因数趋于相同,换热能力明显下降,但热阻呈下降趋势.     

Experimental investigation for the optimization of heat pipe performance in latent heat thermal storage

We investigated the optimum performance of heat pipe in Latent heat thermal energy storage (LHTES), and compared it with copper pipe. Classical plan of experimentation was used to optimize the parameters of heat pipe. Heat pipe fill ratio, evaporator section length to condenser section length ratio i.e., Heat pipe length ratio (HPLR) and heat pipe diameter, was the parameter used for optimization, as result of parametric analysis. Experiment with flow rate of 10 lit./min. was conducted for different fill ratio, HPLR and different diameter. Fill ratio of 80 %, HPLR of 0.9 and heat pipe with diameter of 18 mm showed better trend in charging and discharging. Comparison between the storage tank with optimized heat pipe and copper pipe showed almost 186 % improvement in charging and discharging time compared with the copper pipe embedded thermal storage. Heat transfer between Heat transferring fluid (HTF) and Phase change material (PCM) increased with increase in area of heat transferring media, but storage density of storage tank decreased. Storage tank with heat pipe embedded in place of copper pipe is a better option in terms of charging and discharging time as well heat storage capacity due to less heat lost. This justifies the better efficiency and effectiveness of storage tank with embedded optimized heat pipe.     

轧管机运动稳定性的模糊优化设计

在轧管机运动稳定性优化设计方案中考虑到影响机构设计的各种模糊因素,建立了模糊优化设计的数学模型.在满足曲柄存在条件和传动性能要求条件下,使得主机头运动加速度最小,对曲柄半径、连杆长度、机架距离以及偏距进行了优化设计,并给出了优化方法和结果分析.     

Metamodel-based global optimization using fuzzy clustering for design space reduction

High fidelity analysis are utilized in modern engineering design optimization problems which involve expensive black-box models.For computation-intensive engineering design problems,efficient global optimization methods must be developed to relieve the computational burden.A new metamodel-based global optimization method using fuzzy clustering for design space reduction(MGO-FCR) is presented.The uniformly distributed initial sample points are generated by Latin hypercube design to construct the radial basis function metamodel,whose accuracy is improved with increasing number of sample points gradually.Fuzzy c-mean method and Gath-Geva clustering method are applied to divide the design space into several small interesting cluster spaces for low and high dimensional problems respectively.Modeling efficiency and accuracy are directly related to the design space,so unconcerned spaces are eliminated by the proposed reduction principle and two pseudo reduction algorithms.The reduction principle is developed to determine whether the current design space should be reduced and which space is eliminated.The first pseudo reduction algorithm improves the speed of clustering,while the second pseudo reduction algorithm ensures the design space to be reduced.Through several numerical benchmark functions,comparative studies with adaptive response surface method,approximated unimodal region elimination method and mode-pursuing sampling are carried out.The optimization results reveal that this method captures the real global optimum for all the numerical benchmark functions.And the number of function evaluations show that the efficiency of this method is favorable especially for high dimensional problems.Based on this global design optimization method,a design optimization of a lifting surface in high speed flow is carried out and this method saves about 10 h compared with genetic algorithms.This method possesses favorable performance on efficiency,robustness and capability of global convergence and gives a new optimization strat     

翅片热板散热器的设计

针对功率电子元器件散热的需要,设计一种新型功率电子元器件新型散热器一翅片式平板热管散热器,并通过强度较核了设计的合理性,通过实验检验了设计的可靠性.     

基于遗传算法的小卫星多Agent任务调度优化设计

为了提高小卫星星务系统的自主化、智能化水平,将Agent技术引入到小卫星星务系统的设计中已经成为小卫星星务系统自主运行研究的一个方向.本文提出一种将Agent与小卫星任务相结合进行星务系统设计的方法,利用遗传算法对Agent任务的调度方案进行优化.调度优化设计中综合考虑了最大限度地利用小卫星系统资源和缩短完成任务的时间两个指标,利用遗传算法的交叉和变异,寻求任务调度的最优调度方案.仿真实验表明,该方法能够在满足小卫星任务实时性要求的前提下,使得小卫星有限资源的分配更加优化,使得星务系统在更短的时间内完成更多的任务.     

基于人工神经网络的多学科优化设计研究

多学科优化设计的两大难点是子学科间的信息交换和系统分析计算的复杂性。为此，在一致性约束算法和并行子空间算法基础上，提出了一种基于人工神经网络响应面的多学科优化设计算法，它是一种二级结构的优化方法，即学科层仅满足局部约束，系统层提供一种协调学科间冲突的机制，保证在相关变量和耦合变量上的一致性，使设计方案不断改进。通过某型号飞航导弹系统的优化实例，验证了算法的有效性。     

Comparison of nongradient methods with hybrid Taguchi-based epsilon constraint method for multiobjective optimization of cylindrical fin heat sink

The primary aim of the paper is to compare the different nongradient methods of multiobjective optimization for optimizing the geometry parameters of a cylindrical fin heat sink. The methods studied for comparison are Taguchi-based grey relational analysis, ε (epsilon) constraint method and genetic algorithm. The various responses that have been studied are electromagnetic emitted radiations, thermal resistance and mass of the heat sink. Since the responses are obtained using complex simulation softwares (HFSS—Ansoft for emitted radiations and CFD—Flotherm for thermal resistance), there is no way of calculating the derivates of the objective functions. Hence, the Taguchi design of experiments design is used to derive the linear regression equations for the responses studied, which are then taken as the objective functions to be optimized. A new hybrid method known as Taguchi-based epsilon constraint method has been proposed in this paper for obtaining nondominated Pareto solution set. The results obtained using the proposed method show that the Pareto optimal set is competitive in terms of diversity of the solutions obtained. It is not likely that there exists a solution, which simultaneously minimizes all the objectives using any of the multiobjective techniques implemented. The value path analysis has been done to compare the trade-off among the design alternatives for the chosen multiple objective parameter optimization problem.     

Flow visualization of oscillation characteristics of liquid and vapor flow in the oscillating capillary tube heat pipe

The two-phase How patterns for both non-loop and loop type oscillating capillary tube heat pipes (OCHPs) were presented in this study. The detailed flow patterns were recorded by a high-speed digital camera for each experimental condition to understand exactly the operation mechanism of the OCHP. The design and operation conditions of the OCHP such as turn number, working fluid, and heat flux were varied. The experimental results showed that the representative flow pattern in the evaporating section of the OCHP was the oscillation of liquid slugs and vapor plugs based on the generation and growth of bubbles by nucleate boiling. As the oscillation of liquid slugs and vapor plugs was very speedy, the How pattern changed from the capillary slug flow to a pseudo slug flow near the annular flow. The flow of short vapor-liquid slug-train units was the flow pattern in the adiabatic section. In the condensing section, it was the oscillation of liquid slugs and vapor plugs and the circulation of working fluid. The oscillation flow in the loop type OCHP was more active than that in the non-loop type OCHP due to the circulation of working fluid in the OCHP. When the turn number of the OCHP was increased, the oscillation and circulation of working fluid was more active as well as forming the oscillation wave of long liquid slugs and vapor plugs in the OCHP. The oscillation flow of R-142b as the working fluid was more active than that of ethanol and the high efficiency of the heat transfer performance of R-I42b was achieved.     

多目标优化问题的理想有效解

针对多目标优化问题的特点和困难性,说明采用极小化极大值的求解策略,决策者从非劣解集中可以获得比较理想的有效解。     

蛇形管生产线托管器的改进设计

针对传统杠杆拨叉式托管器存在的缺点,将托管板的工作面设计成阶梯形,料架增加了一个用于存储待取料管的台阶。从而使托管器降低能耗,工作可靠。     

作业调度可视化服务优化方法研究

随着制造业信息化服务研究应用的扩展,可视化服务在企业资源计划中的应用是当前一个值得研究的重要问题.在对国内航空企业作业调度的现状调查分析的基础上,针对存在的复杂产品制造作业调度优化问题,提出了作业调度可视化服务的优化目标、方法;从产品数据和作业调度信息服务共性、共享的角度构建可视化服务模型,给出了可视化服务优化模型等;对优化算法设计作了深入探讨.     

New optimization method, the algorithms of changes, for heat exchanger design

Heat exchangers are widely used in the process engineering such as the chemical industries,the petroleum industries,and the HVAC applications etc.An optimally designed heat exchanger cannot only help the optimization of the equipment size but also the reduction of the power consumption.In this paper,a new optimization approach called algorithms of changes (AOC) is proposed for design and optimization of the shell-tube heat exchanger.This new optimization technique is developed based on the concept of the book of changes (I Ching) which is one of the oldest Chinese classic texts.In AOC,the hexagram operations in I Ching are generalized to binary string case and an iterative process,which imitates the I Ching inference,is defined.Before applying the AOC to the heat exchanger design problem,the new optimization method is examined by the benchmark optimization problems such as the global optimization test functions and the travelling salesman problem (TSP).Based on the TSP results,the AOC is shown to be superior to the genetic algorithms (GA).The AOC is then used in the optimal design of heat exchanger.The shell inside diameter,tube outside diameter,and baffles spacing are treated as the design (or optimized) variables.The cost of the heat exchanger is arranged as the objective function.For the heat exchanger design problem,the results show that the AOC is comparable to the GA method.Both methods can find the optimal solution in a short period of time.     

A thermal design method for the performance optimization of multi-stream plate-fin heat exchangers

An optimization design method based on field synergy principle is developed for Multi-stream plate-fin heat exchangers (MPHEs) with a segmented differential model. The heat exchanger is divided into a number of sub-exchangers along the main stream, and each sub-exchanger consists of N passages along the height of the exchanger. Compared with the traditional heat exchanger design, this method allows temperature and pressure fields to be obtained via coupling calculation with consideration of variable physical properties and the axial heat loss of the heat exchanger. Finally, the heat exchanger is optimally designed using a temperature-difference uniformity optimization factor based on field synergy principle. This design model can provide an accurate temperature field and pressure field, because the stream properties are determined by the mean temperature and pressure of each local sub-exchanger. Optimum results indicate that the temperature distribution on the cross section of the heat exchanger is relatively uniform and that the temperature difference of heat transfer for each stream is always a small value. These characteristics prove the feasibility and effectiveness of this design model. In this paper, a case of five stream plate-fin heat exchangers for an ethylene plant is designed under a practical cold box operating condition with the proposed model, the structure and heat transfer of which are optimally determined. The design model and optimization method proposed in this work can provide theoretical and technical support to the optimization design of MPHEs.

     

上海光源前端高热负载挡光器的结构设计与优化

为了有效处理上海光源前端挡光器接收的高热负载,研究了挡光器的结构设计及其优化方法。选用高导热性、高强度的GlidCop AL-15制造挡光器吸收体,采用直接水冷和掠入射结构提高其热缓释能力。以对流换热系数和压力降为评价指标,选用佩图克方程和达尔西-韦斯巴赫方程优化冷却水路,通过热分析得到了不同参数下挡光器的温度和热应力分析结果,从而确定了挡光器的结构设计优化参数。优化后挡光器的水路直径为6mm,水路到光照面的距离为9mm,光照面接线处圆角≥2mm,且水路与光束方向基本平行。与初始结构相比,优化后挡光器的最高整体温度和最高冷却壁温度分别下降约8%和1/4,最大等效应力降低了1/2左右,完全满足上海光源前端部件的设计要求。目前,应用优化参数设计的挡光器已应用于上海光源实际工程中。     

Journal bearing design using multiobjective genetic algorithm and axiomatic design approaches

This paper describes the optimum design methodology for improving operating characteristics of fluid-film steadily loaded journal bearings. This methodology consists of (1) a simplified closed form solution to accelerate the computation, (2) finite difference mass conserving algorithm for accurate prediction of lubricant flow and power loss, (3) Pareto optimal concept to avoid subjective decision on priority of objective functions, (4) a genetic algorithm to deal with multimodal nature of hydrodynamic-bearing and develop a Pareto optimal front, (5) fitness sharing to maintain genetic diversity of the population used in genetic algorithm, and (6) axiomatic design to provide inside of objective functions and design variables. In the optimum design of journal bearings, the design variables such as radial clearance, length to diameter ratio, groove geometry, oil viscosity and supply pressure are used to simultaneously minimize oil flow and power loss. A step-by-step procedure, graphs and tables are presented to demonstrate the concept and effectiveness of suggested design methodology.     

人工神经网络在结构优化设计中的应用

将有限元法与人工神经网络相结合,利用人工神经网络的非线性映射能力,训练一个可以预测不同输入参数时的结构应力或位移等信息的人工神经网络,使其可以方便地代入到优化设计程序中,其中重点介绍的是人工神经网络的教师样本构造问题。用一实例详细说明了方法的使用过程,结果表明了这种方法的有效性。     

Optimum design of short journal bearings by enhanced artificial life optimization algorithm

This paper presents an optimum design of high-speed short journal bearing using an enhanced artificial life algorithm (EALA) to compute the solutions of optimization problem. The proposed hybrid EALA algorithm is a synthesis of an artificial life algorithm (ALA) and the random tabu search method (R-tabu method) to solve some demerits of the ALA. The emergence is the most important feature of the artificial life which is the result of dynamic interaction among the individuals consisting of the system and is not found in an individual. The artificial life optimization algorithm is a stochastic searching algorithm using the feature of artificial life. The feature of R-tabu method, which prevents converging to the local minimum, is combined with the ALA. One of the features of the R-tabu method is to divide any given searching region into several sub-steps. As the result of the combination of the two methods, the EALA not only converges faster than the ALA, but also can lead to a more accurate solution. In addition, this algorithm can also find all global optimum solutions. We applied the hybrid algorithm to the optimum design of a short journal bearing. The optimized results were compared with those of ALA and successive quadratic programming, and identified the reliability and usefulness of the hybrid algorithm.     

A new method based on LPP and NSGA-II for multiobjective robust collaborative optimization

The multiobjective robust collaborative optimization framework consists of optimization both at the system and autonomous subsystem levels. Linear physical programming is used in the system level optimization, which avoids the difficulty in choosing the multidimensional Pareto set. The non-dominated sorting genetic algorithm (NSGA-II) is used in the subsystem optimization with physical objectives. The interdisciplinary incompatibility function and physical objectives have different priority levels. At the first priority level, the best individual should be in the feasible region of the subsystem. At the second priority level, the interdisciplinary incompatibility function of the best individual should be no more than the feasibility threshold. The physical objectives are improved after the achievement of the above levels. A method for producing initial population with feasibility and diversity is proposed to improve the calculation efficiency and accuracy of the subsystem optimization at the first priority level. A method for setting dynamic feasibility threshold is proposed for the non-dominated sorting to help the physical objectives to obtain better solutions at the second priority level. Finally, the results of the speed reducer show that the presented method is efficient.