Multidisciplinary optimization of a butterfly valve

A butterfly valve is a type of flow control device, typically used to regulate fluid flow. This paper proposes a new process to meet desired needs in valve design that is characterized by the complex configuration. First, the need is identified according to the valve user/company, and then the problem is defined with a characteristic function. Second, the initial model of valve is made, and then the initial analysis including fluid and/or structural analysis is carried out to predict the fluid and/or structural performance of the valve. Third, the optimization in the form of mathematical functions, which considers single or multiple objective and/or discipline, is handled. This part includes the design of computer experiment, approximation technique, topology optimization and sizing optimization. Finally, the validation experiment is conducted based on the optimum result to verify the accuracy of the optimization. An example is provided to confirm the availability of the process proposed here.     

遗传算法在流体机械优化设计中的应用

作为一种全新的随机优化方法 ,遗传算法已广泛地应用于透平机械设计的多个方面 ,例如遗传算法直接用于气动元件的形状优化设计 ,遗传算法与一定的计算流体动力学方法结合参与流场的分析和计算等等。本文是对遗传算法在流体机械优化设计方面应用的一个综述。     

Fluid-dynamic analysis and multi-objective design optimization of piezoelectric servo valves

This paper proposes an effective methodology for the fluid-dynamic design optimization of the main spool of a piezoelectric servo valve. The aim is to improve global performances of the piezoelectric servo valve by reducing the flow force acting on the main spool and the mass of the main spool. The main disturbance forces acting the main spool were analyzed. The steady-state flow force acting on the main spool was derived and the relationship between the flow force and the design parameters of the main spool was established. The design problem of the main spool was formulated mathematically as a multi-objective optimization problem. The minimum steady-state flow force and the minimum mass of main spool were considered as optimization objectives. The elitist non-dominated sorting genetic algorithm (NSGA-II) was applied and a set of Pareto-optimal solutions was calculated. The optimized results were analyzed and the final design parameters of the main spool were selected for the simulation analysis and experimental research. The computational fluid dynamics (CFD) simulation was employed to calculate the forces acting on the main spool. Simulation results show the flow force acting on the optimized main spool is significantly reduced. The unoptimized and optimized main spools were machined and experimental study was performed. Results show that the piezoelectric servo valve equipped with the optimized main spool has better response performance and dynamic bandwidth. The dynamic bandwidth is measured to 172 Hz under the amplitude attenuation of −3 dB. Compared with the piezoelectric servo valve with unoptimized main spool, the dynamic bandwidth of the piezoelectric servo valve with optimized main spool is increased by 26%.     

偏心蝶阀不同串联方式的流动阻力特性

应用数值计算软件对某偏心蝶阀进行了数值模拟,得出了其流场特性,其流动阻力特性与已知试验数据吻合较好,说明了数值模拟模型及方法的正确性.并且还从降低管路系统阻力损失的角度,对两个蝶阀串联布置时的流动状态进行了研究.结果表明,相邻偏心蝶阀不同的安装角度对其整体的阻力损失影响不大,可以根据现场实际要求灵活布置.该结论有一定的工程参考价值.     

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     

A hybrid of surrogate model and MIGA method for optimization and compensation of steady-state flow force on water hydraulic HSV

In this research, a hybrid of surrogate model and Multi-island genetic algorithm (MIGA) is proposed for optimization and compensation of steady-state flow force on water hydraulic high-speed on-off valve (HSV) driven by voice coil motor. Firstly, a dynamic model on the spool of HSV is established, and the effects of spool displacement, spool half-cone angle, valve stem diameter and inlet pressure on the steady-state flow force of HSV are analyzed through the CFD simulation. Secondly, a quadratic response surface model is set up based on design of experiment (DOE) to analyze interactions of key parameters on steady-state flow force. MIGA is proposed to optimise the structural parameters of HSV, and the optimization results are analyzed and verified by CFD simulations. Simulation results demonstrate that the steady-state flow force is reduced significantly. Finally, the steady-state flow force in the optimized structure of HSV is also verified experimentally. The experiment results exhibit that the optimized spool can compensate about 71% for the steady-state flow force, then reduce about 15% the energy consumption of HSV. This research will provide the guide for the design and engineering application of HSV.     

基于CFX的大口径蝶阀的流场分析及结构优化

青海尕曲水电站大口径三偏心主控蝶阀在小开度工况下振动强烈,本文利用其二维图纸建立了蝶阀在不同开度下的流道模型,并利用CFX软件对其流场进行了数值模拟。数值分析结果表明:5%~30%开度区间内蝶阀下游的涡街现象强烈。同时,对蝶板结构进行了优化,优化前后分析结果对比表明:改进后蝶阀流场的涡街效应明显减弱,有效预防涡街共振的发生,为以后大型蝶阀的设计提供了参考。     

偏心蝶阀水力特性的数值模拟与分析

运用计算流体力学 (CFD)方法对一种偏心蝶阀的水力特性进行数值模拟计算 ,获得了流道内详细的三维流场参数分布以及蝶阀的压降、流量与水动力矩的水力特性曲线。从计算出的三维流场可以清楚地掌握影响阀门工作的重要因素 ,如各种开度下阀后的流动分离状态 ,以及蝶板上压力低于汽化点从而易发生气蚀的部位等 ,而水力特性曲线则可直接提供设计参数     

Geometric optimization and performance analysis of radial MR valve using Taguchi orthogonal experiment method

Aiming at the problems of increasing external dimensions and deteriorating key performance indicators in the design process of magnetorheological (MR) valve by using structural optimization method, a geometric optimization design methodology for the optimal design of a MR valve structure under specific volume constraints is proposed in this article. The optimization methodology couples the finite element model (FEM) constructed in COMSOL software with the Taguchi orthogonal experiment and response surface technology to build an approximate response surface function for the identified independent variables. Suitable optimization algorithms are then utilized to determine the optimal geometry of the MR valve, thereby maximizing the valve performance. Firstly, a radial MR valve with a single excitation coil was presented, and its structure and working principle were also elaborated. A mathematical model of the pressure drop was derived on the basis of the Bingham-Papanastasiou non-Newtonian constitutive model of MR fluid and the magnetic circuit had been analyzed with the FE analysis methodology. Then, a second-order response surface model (RSM) had been fitted for the magnetic flux density in the radial flow channel and spool region of the radial MR valve based on the Taguchi orthogonal experimental design. The fitted model was a function of the four independent variables of the radial MR valve, and the accuracy of the developed response surface function over the entire design space had also been estimated. Meanwhile, predictions made by the RSM and FE models were evaluated by analysis of variance and it was exhibited that the RSM model’s results agree with FE result fairly. Subsequently, the geometric optimization problem had been formulated for the constructed RSM exploiting the genetic algorithm to find the global optimum geometrical parameters of the radial MR valve. Furthermore, the experimental test rig was setup to explore the pressure drop and the response time characteristics of the initial and optimal radial MR valve as well as the dynamic performance of the MR valve controlled cylinder system under different excitation conditions. The experimental results show that under the applied current of 2 A, the pressure drop and adjustable coefficient of the optimal radial MR valve observably increased with values of 3.15 MPa and 5.40, respectively, when compared to 2.11 MPa and 4.22 of their respective initial values. Also, at the applied current of 1.25 A, the damping force of the MR valve controlled cylinder system enlarged by 46 %, with its optimal value being 3.65 kN and initial value as 2.50 kN, which was an excellent verification of the correctness of the RSM and the effectiveness of the optimal design.

     

T型管流场混合多相流与欧拉多相流模型的数值研究

以计算流体动力学(CFD)的多相流数值计算理论及方法为基础,对处于复杂工况的T型管连接装置腔内流场进行了数值模拟分析,采用标准湍流模型和标准壁面函数对T型管接头内部流场进行了数值模拟;同时以混合模型求得的解作为用欧拉多相流模型的初始条件,采用欧拉多相湍流模型进行了对T型管接头内部流场数值计算.最后对两种模型计算得到的T型管接头内部流场的压力场、速度场及气相的体积分数(VOF)分布进行了对比分析.计算结果将指导的结构优化设计及失效分析.     

长寿可靠型连杆式切断蝶阀设计研究开发

长寿可靠型连杆式切断蝶阀是一种长寿、可靠、安全、高效的中高温气体切断蝶阀,在高炉炼铁系统中用作煤气、空气或烟气管道的切断阀门,应用范围越来越广泛,逐步取代了笨重的闸阀。主要介绍了长寿可靠型连杆式切断蝶阀新的设计理念和结构优化设计方案,对蝶阀四杆机构运动轨迹进行了研究分析,提出了密封补偿机理研究分析理论,优化了密封副设计和材质选择。还介绍了长寿可靠型连杆式切断蝶阀寿命试验及其结果,为连杆式切断蝶阀的工作状况、实际性能等各方面的研究提供了试验数据支撑,对阀门结构优化设计提供了依据。寿命试验对比测量了纳米材料复合电镀自润滑轴套与普通铜基自润滑轴套磨损量,为深入研究长寿可靠型连杆式切断蝶阀长寿安全可靠免维护性能提供了试验条件和技术支撑。     

液力变矩器叶栅系统三维优化设计方法研究

为实现液力变矩器叶栅系统的完全三维设计及其优化,开发了一套包含束流初值搜索、循环圆与叶形的参数化设计、网格划分、流场分析、试验设计和优化算法在内的三维优化设计系统,并且为各环节开发了相应设计工具。快速的束流初值遗传算法搜索为三维多目标优化提供合理初值;循环圆设计工具可以快速灵活地给出平面分布和几何约束,而后叶形设计分别为泵轮、涡轮和导轮叶片指定叶片角度和加厚形式,空间三维叶片设计整合前面设计结果生成叶片空间姿态,同时在整个叶片成型过程中完全采用参数驱动的形式;为对各个参数对传动性能的影响有准确反映,对设计结果进行了自动的网格划分和数值分析,并将分析结果反馈给优化设计环节以及后续相关部件的有限元分析环节;优化设计采用试验设计与全局优化算法相结合以提高设计的稳健性,加速收敛。通过对D400型液力变矩器的三维优化,得到了一组新的优化叶片,传动特性得到提高、同时减少了设计用时和优化迭代次数,表明叶栅的三维优化设计系统是开发新型性能优良液力变矩器的更为有效和准确的工具。     

Flow analysis of a switching valve with innovative poppet head geometry by means of CFD method

The article presents an analysis of flow through a differential switching valve installed inside a throttle-check valve block. The valve is mounted in a sandwich type arrangement together with a control valve according to ISO 4401 standard. This type of block arrangement is popular and commonly used in hydraulic drive systems. The development of a typical throttle-check valve using a differential switching valve makes it possible to add a secondary fluid stream and thus increase the inflow rate to an actuator, which is particularly important in fixed-delivery pump systems. Due to the limited range of valve dimensions and the need to adapt flow paths to connection ports, channels of complex geometry are made inside the valve block. Therefore, the main aim of the work was to properly profile geometry of the differential switching valve spool in order to obtain a smooth opening in the entire displacement range. A 3D model of flow paths was built and CFD analysis was carried out. The obtained results of numerical simulations have been confirmed experimentally on a test bench. The CFD analysis allowed values of velocity and pressure profiles as well as axial flow force acting on the spool to be determined. The proposed new shapes of the spool head geometry significantly increase the spool head operating range. Although flow rate in the initial phase of switching valve opening was reduced, the amplitude of fluid flow fluctuations also decreased.     

直角截止阀噪声特性分析及优化设计

针对直角截止阀振动噪声较大的实际问题,建立了某型号直角截止阀的流场结构,并利用CFD数值计算方法对其在不同开度下的压力、速度和湍流动能进行了计算。计算结果显示,直角截止阀在阀口位置具有明显的空化现象和湍流噪声,且阀口开度越小,噪声问题越明显。针对该问题,对直角截止阀的阀芯、阀座和回油腔流道结构进行了低噪声优化设计和计算分析。计算结果表明,优化后的新型直角截止阀与原阀相比,空化系数减小了10%以上、湍流噪声降低了20 dB以上,具有良好的低噪声性能。     

Investigation of the mechanical behavior of a flexible solid metal seal for a cryogenic butterfly valve

Seat tightness at the fully shut position should be a consideration in the development of a butterfly valve for use in a liquefied natural gas (LNG) vessel. A flexible solid metal seal offers sufficient tightness of the butterfly valve and meets the specifications for cryogenic temperature. In the present study, characteristics for a cryogenic butterfly valve, such as the flow coefficient and the pressure loss coefficient, were estimated by numerical fluid analysis carried out to simulate 3-D flow and to study performance as it was affected by the opening angles of the valve disc. A design criterion to ensure the seat tightness of the butterfly valve at the fully shut position was proposed, in which the contact pressure between the metal seal and the valve disc would be compared with the fluid pressure. Numerical structural analysis showed that the contact pressure can be calculated by simulation of the frictional contact behavior on the surface of the metal seal and the valve disc. As a result, an adequate flexibility of the metal seal and the valve disc was required in order to accomplish a contact pressure that would be high enough to satisfy the seat tightness requirement. Under cryogenic temperature, thermal shrinkage caused the metal seal to adhere closely to the valve disc periphery at both sides and raised the contact pressure to a relatively high value, though there was no contact across a small area at the center position, which is susceptible to leakage. An additional displacement of the metal seal and the valve disc appeared at an operating fluid pressure of 6.9 bar and produced sufficient contact pressure at the no-contact area. This was verified by experimental leakage tests performed at room and cryogenic temperatures.     

连杆蝶阀的流场分析

以往的连杆蝶阀设计,无法确定介质对阀门过流件的压强及受力,影响了蝶阀的设计。针对这一现状,文中采用COSMOSFloworks软件对国内某重工集团的DN1800蝶阀进行了流场分析,依据运动轨迹对不同开度时阀板的平均压强、压差和受力等数据进行了提取,描述了阀板开启过程中流体流动的全貌。分析结果表明,阀板在刚开启时受力最大,为230731N,过流件的强度分析及液压缸的选型应按此工况进行;全开时,阀板受到向上的力为18504N,此力是阀板过开的动力源。     

基于CFD的离心压缩机整级性能优化设计

本文采用CFD技术研究离心压缩机整级性能优化设计方法.首先用一元理论进行初始设计,应用全三维流场分析的方法分析叶轮、扩压器以及回流器叶片参数变化对压缩机性能的影响.在此基础上,对主要几何参数进行了优化设计.研究结果表明;通过在压缩机运行过程中调节扩压器叶片的角度,可以使压缩机的最大效率和工况范围均得到改善.对于本模型的压缩机,效率可提高3％以上.优化设计后压缩机整级气动性能得到明显改善.     

Application of rapid prototyping and computational fluid dynamics in the development of water flow regulating valves

Water flow regulating valves are widely used in instant water heaters to vary the rate of water flow. The water flow regulation from the valve has to be linear so that the temperature at the outlet is uniform. The shapes of valve trim affect the flow rate and have to be confirmed before releasing the designs for manufacture. In this project, the flow rate regulating characteristics were improved for a flow regulating valve with the application of rapid prototyping (RP) and computational fluid dynamics (CFD). In the development of flow regulating valves, precise, functional prototypes were required. Design concepts of three valve trim designs were evaluated applying different RP techniques and CFD analysis. Prototypes from different RP systems were used as functional models. Over the product development cycle, RP and CFD analysis stages played an important role particularly in the design selection stage. Finally, comparisons of RP samples from various RP processes and the results of CFD analysis were made on the flow rate and flow regulation. Based on these comparisons, the best design was chosen for manufacture of the valves.     

基于近似模型的高速列车头型多目标优化设计

为改善高速列车气动性能,建立一套高效的多目标气动优化设计方法,对流线型头型进行多目标气动优化设计。建立高速列车流线型头型三维参数化模型,并提取5个优化设计变量;为减少优化设计时间,利用最优拉丁超立方设计方法在优化设计空间中进行均匀采样,利用计算流体力学方法获得对应于各个采样点的气动载荷,利用Kriging代理模型构建优化设计变量和气动载荷之间的近似模型;利用多体系统动力学方法计算气动载荷作用下的高速列车轮重减载率;以气动阻力和轮重减载率为优化目标,利用多目标遗传算法NSGA-II对高速列车流线型头型进行多目标优化。优化设计变量和优化目标均呈现收敛的趋势,采用Kriging近似模型优化计算的Pareto前沿与采用CFD（Computational fluid dynamics,CFD）优化计算的Pareto前沿较为接近。优化后高速列车的气动阻力最多可降低3.27%,轮重减载率最多可降低1.44%,气动阻力最优的头型与轮重减载率最优的头型的主要差异在于中部辅助控制线的变化,前者向内凹,后者则向外凸。     

某超高压电磁球阀流场特性分析

目前高速高压是液压系统的发展方向之一,其中液压元件的超高压化在提升液压系统功重比的同时,也会带来一系列新的问题。针对某超高压电磁球阀流量及阀芯受力情况难以测量的问题,建立物理模型,采用CFD方法对电磁阀开启过程进行仿真。通过流场的有限元分析,得到阀芯所受液压力、流量随阀口开度的变化曲线及压力、速度变化云图,进一步分析了阀口流量饱和特性,并结合分析结果对电磁球阀流道结构的进一步优化设计提出理论支持。