基于遗传算法的风力机塔架最优化设计方法

探讨了遗传算法在风力机塔架结构优化设计中的应用.通过对经典遗传算法进行改进,建立了存在约束条件的遗传算法优化设计模型;考虑结构受力特点,给出了塔架体系在屈曲性能约束条件下的最优化设计方法.另外,针对遗传算法容易收敛到局部最优点的缺陷,改变各变量相应初始界限值,进行两次遗传算法操作运算,使工作效率提高,且结果更为精确.最后,对某风力机塔架进行在简化荷载作用下的最优化设计,得到了较满意的结果.     

Genetic algorithms development for multiobjective design optimization of compressor cascade

INTRODUCTIONTurbomaChinery,especiallycompressorcascade,optimumdesignpresentsagrandchallengetonumericaloptimization.Thegoalofcompressorcascadedesignistoproducethehighestpressurerisewiththelowesttotalpressurelossattheconstantflowcondition.Parameterofpr...     

Horizontal axis wind turbine systems: optimization using genetic algorithms

A method for the optimization of a grid‐connected wind turbine system is presented. The behaviour of the system components is coupled in a non‐linear way, and optimization must take into account technical and economical aspects of the complete system design. The annual electrical energy cost is estimated using a cost model for the wind turbine rotor, nacelle and tower and an energy output model based on the performance envelopes of the power coefficient of the rotor, C_P, on the Weibull parameters k and c and on the power law coefficient α of the wind profile. In this study the site is defined with these three parameters and the extreme wind speed V_max. The model parameters vary within a range of possible values. Other elements of the project (foundation, grid connection, financing cost, etc.) are taken into account through coefficients. The optimal values of the parameters are determined using genetic algorithms, which appear to be efficient for such a problem. These optimal values were found to be very different for a Mediterranean site and a northern European site using our numerical model. Optimal wind turbines at the Mediterranean sites considered in this article have an excellent profitability compared with reference northern European wind turbines. Most of the existing wind turbines appear to be well designed for northern European sites but not for Mediterranean sites. Copyright © 2001 John Wiley & Sons, Ltd.     

Aerodynamic Optimum Design of Transonic Turbine Cascades Using Genetic Algorithms

INTRoDUCTIoNInmodernturbomachinery,withtheincreasingstageload,thetransoniccascadesbecomemorewidelyused,sothedesignofhighperformancetransoniccas-cadesisacriticaJpracticalproblem.Performanceop-timizationofaerodynamicshapeplaysanimportantroleinthedesigntasksofttirbomachinery,andisanactiveresearchfield.Awidevarietyoftechniqueshavebeendeve1opedtofacethisprobleml1].FuIthermethodsbasedonartificialintelligence-expertsystemtechniqueshavealsobeenintroducedl2].Butthediffusionofauto-matedshapedesigni…     

Investigation of Internal Flow in Ultra—Highly Loaded Turbine Cascade by PIV Method

IntroductionSeveral investigations for highly loaded turbineblades have been tried in order to increase the turbineloading and the turbine inlet tempefature["']. Thehighly loaded tUrbine blades are able to reduce both thenumber of blades and the stages. Thus, the highly loadedturbine cascades can reduce the weight and theproduction cost of turbojet-engines. However, in order toachieve the high loading of the turbine blade, the highturning angle is necessmp. As the consequence, the strongt…     

Centrifugal compressor blade optimization based on uniform design and genetic algorithms

An optimization approach to centrifugal compressor blade design, incorporating uniform design method (UDM), computational fluid dynamics (CFD) analysis technique, regression analysis method and genetic algorithms (GA), is presented. UDM is employed to generate the geometric information of trial samples whose performance is evaluated by CFD technique. Then, function approximation of sample information is performed by regression analysis method. Finally, global optimization of the approximative function is obtained by genetic algorithms. Taking maximum isentropic efficiency as objective function, this optimization approach has been applied to the optimum design of a certain centrifugal compressor blades. The results, compared with those of the original one, show that isentropic efficiency of the optimized impeller has been improved which indicates the effectiveness of the proposed optimization approach. __________ Translated from Journal of Power Engineering, 2007, 27(5): 713–716 [译自: 动力工程]     

变桨距风力机叶片的气动优化设计

首先利用Wilson方法进行叶片的外形初步设计,然后以设计攻角作为变量,以额定风速下功率系数最大为优化目标,建立了1 MW变桨距风力机叶片气动外形优化模型,采用遗传算法进行了优化再设计。通过对3叶片1 MW风力机进行的气动性能评价结果表明,优化后的风力机具有更好的气动性能,说明采用该优化方法进行变桨距风力机设计具有明显的优越性。     

Compact modeling approach using genetic algorithms for accurate thermal simulation

In this paper, we propose a technique that uses thermal measurement results for improved accuracy in thermal simulation of electronic apparatus. Because the modeling of the electronic components in such apparatus has hitherto been very poor, the thermal simulation results cannot achieve the required accuracy. To solve this problem, we first represent a component as a set of cubic blocks with equivalent thermal conductivity and contact thermal resistance values, and then identify these values by using the thermal measurement results for the component. We regard the identification of parameters as an optimization problem that involves minimizing the difference between the predicted and measured results. To solve the problem, we combine genetic algorithms and a thermal simulation tool. Our technique was successfully applied to the construction of an accurate thermal model, which we validated by using thermal measurement results. © 2000 Scripta Technica, Heat Trans Asian Res, 30(1): 28–39, 2001     

Using genetic algorithms for the determination of an heat transfer coefficient in three-phase inverse Stefan problem

In the paper, an example is presented of the application of a genetic algorithm to a design inverse Stefan problem. The problem consists in the reconstruction of the function which describes the heat transfer coefficient, where the positions of phase change moving interfaces are well-known. In numerical calculations, the Tikhonov regularization, a genetic algorithm and a generalized alternating phase truncation method were used. The featured examples of calculations show a very good approximation of the exact solution.     

船用增压锅炉烟气涡轮级叶栅三维湍流流动的数值模拟

以某船用增压锅炉涡轮增压机组烟气涡轮级为研究对象,采用三维数值模拟技术和“混合平面”方法传递级间参数,利用标准κ-ε双方程湍流模型和耦合隐式求解器,通过求解三维雷诺平均守恒Navier—Stokes方程,来模拟烟气涡轮级叶栅三维湍流流动。文中给出了烟气涡轮级叶栅出口静压、总压、速度以及总温和静温等各参数的变化规律,对于烟气涡轮叶栅气动优化设计具有一定的参考价值。     

Reliability design method for steam turbine blades

Based on theories of probability and statistics, and taking static stresses, dynamic stresses, endurance strength, safety ratios, vibration frequencies and exciting force frequencies of blades as random variables, a reliability design method for steam turbine blades is presented. The purport and calculation method for blade reliability are expounded. The distribution parameters of random variables are determined after analysis and numerical calculation of test data. The fatigue strength and the vibration design reliability of turbine blades are determined with the aid of a probabilistic design method and by interference models for stress distribution and strength distribution. Some blade reliability design calculation formulas for a dynamic stress design method, a safety ratio design method for fatigue strength, and a vibration reliability design method for the first and second types of tuned blades and a packet of blades on a disk connected closely, are given together with some practical examples. With these methods, the design reliability of steam turbine blades can be guaranteed in the design stage. This research may provide some scientific basis for reliability design of steam turbine blades. __________ Translated from Chinese Journal of Applied Mechanics, 2007, 24(3): 331–335 [译自: 应用力学学报]     

Experimental Studies on Heat Transfer in the Tip Gap of a Sectorial Turbine Cascade

ＥｘｐｅｒｉｍｅｎｔａｌＳｔｕｄｉｅｓｏｎＨｅａｔＴｒａｎｓｆｅｒｉｎｔｈｅＴｉｐＧａｐｏｆａＳｅｃｔｏｒｉａｌＴｕｒｂｉｎｅＣａｓｃａｄｅＥｘｐｅｒｉｍｅｎｔａｌＳｔｕｄｉｅｓｏｎＨｅａｔＴｒａｎｓｆｅｒｉｎｔｈｅＴｉｐＧａｐｏｆａＳｅｃｔｏｒｉａ...     

CAD技术在舰用燃气轮机设计中的应用

本文论述了计算机辅助设计(CAD)技术及其在舰用燃气轮机设计工作中应用的前景,并提出了舰用燃气轮机CAD 系统实现的方案和方法。     

An integrated approach for optimal design of micro gas turbine combustors

The present work presents an approach for the optimized design of small gas turbine combustors, that integrates a 0-D code, CFD analyses and an advanced game theory multi-objective optimization algorithm. The output of the 0-D code is a baseline design of the combustor, given the required fuel characteristics, the basic geometry (tubular or annular) and the combustion concept (i.e. lean premixed primary zone or diffusive processes). For the optimization of the baseline design a simplified parametric CAD/mesher model is then defined and submitted to a CFD code. Free parameters of the optimization process are position and size of the liner hole arrays, their total area and the shape of the exit duct, while different objectives are the minimization of NO_x emissions, pressure losses and combustor exit Pattern Factor. A 3D simulation of the optimized geometry completes the design procedure. As a first demonstrative example, the integrated design process was applied to a tubular combustion chamber with a lean premixed primary zone for a recuperative methane-fuelled small gas turbine of the 100 kW class.     

Calculation Error of Numerical Solution for a Boundary—Value Inverse Heat Conduction Problem

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Experimental Investigations of the Three—Dimensional Flow in a Large Deflection Turbine Cascade with Tip Clearance

INTRoDUCTI0NThetipleakaeflowisnowrecognizedasanimpor-tantsourceoflossesinbothcompressorsandturbines,asasourceofcoolingprobleminturbinesandasourceofinstabilityincomPressorsandfans.Manyturbo-maChinimPellersarenotshroudedandtheleakaeflowthroughthetipgaPofthebladeisanunavoidablefaCtorwhichdeterioratestheperformance.Den-tonandCumpsty[1]melltionedabouttwodistinctandequallyimportantaspects.tothetipclearanceflows.First,thereisareducti0ninthebladeforce,there-fore,theworkdone.Thisoccursbecausethe…     

Simulating novel gas turbine conditions for materials assessment: cascade design and operation

Integrated gasification combined cycles can incorporate pre-combustion carbon capture. High-H₂ syngas produces high H₂O levels after combustion, potentially accelerating gas turbine component damage. Determining materials systems’ suitability for this novel environment requires exposures in representative environments. Thus, an existing 0.7?MW burner rig was modified to generate the combustion environment and incorporate a cascade of 15 air-cooled turbine blades. Computational fluid dynamic calculations using blade dimensions and flow requirements supported the cascade design and determined blade placement within the gas flow. Trials of the modified unit have shown that a simulated combusted H₂-rich syngas composition was generated at gas temperatures ≤1440°C. A 1000?h exposure has been carried out with thermal barrier coated blades to demonstrate the operation of the unit.

This paper is part of a thematic issue on the 9th International Charles Parsons Turbine and Generator Conference. All papers have been revised and extended before publication in Materials Science and Technology.     

兆瓦风力发电机系统可靠性设计理论研究

在分析兆瓦风力发电机系统的基础上,提出了兆瓦风力发电机发电系统可靠度的基本概念及计算方法,建立了可靠度最优分配的数学模型及最优兆瓦风机发电系统可靠性设计的数学模型。     

Experimental Studies on The Mechanism and Control of Secondary Flow Losses in Turbine Cascades

This paper summarizes the results of the authors' 4 year experimental studies on the secondary flow losses in turbine cascades. Cascade wind tunnel experiments were carried out concerning the influence of aspect ratios, incidence, turning angles and outer endwall divergent angles in order to unveil the evolution mechanism of secondary flow losses in turbine cascades without end clearance. Some methods for controlling the secondary flows are investigated including the blade leaning, blade cambering, endwall convergence and leading edge extension at two ends of the blade.     

Design method of guide vane for Wells turbine

Guide vanes are installed in the Wells turbine in order to improve its efficiency, self-rotating characteristics and off design performance with stall. This work attempts to explain the role of these guide vanes on the basis of momentum theory. It is shown that the upstream vanes are more effective in enhancing efficiency than the downstream ones. A design method for guide vanes is suggested based on experimental data and potential theory. Experimental studies carried out by the author confirm the theory proposed.