共查询到17条相似文献,搜索用时 203 毫秒
1.
2.
3.
基于控制理论的气动设计方法作为一种基于梯度的优化方法,通过引入伴随系统计算目标函数的敏感性导数,大大降低设计成本.本文将基于控制理论的气动设计方法应用到透平叶栅的气动反问题中,应用Euler方程研究了二维叶栅的压力反设计问题,并讨论了该方法具体实施中的关键问题,包括采用非均匀B样条进行二维叶栅造型;应用Thompson时间相关边界条件理论进行伴随方程特征分析;研究伴随方程的数值求解方法,构造伴随方程的耗散通量.通过算例证明了该气动设计方法适用性好,速度快,可以大大节约计算成本. 相似文献
4.
基于离散伴随方法的透平叶栅反设计 总被引:1,自引:0,他引:1
研究构建了基于离散伴随方法的叶轮机械叶栅气动反设计系统,将离散伴随系统从无黏环境扩展到了黏性环境,编程实现了黏性离散伴随求解器;改善了叶栅参数化方式并重新编程实现了叶栅参数化程序,解决了叶栅参数化过程中叶栅尾缘附近区域型线波动的问题。利用该系统对某二维跨声速透平叶栅在给定叶型壁面目标压力分布的情况下,通过构造目标函数将叶栅反设计问题转化为气动优化设计问题,成功进行了气动压力反设计。结果证明本文建立的叶栅反设计系统能够有效进行压力反设计,验证了本文建立的基于离散伴随方法叶轮机械叶栅气动反设计方法的正确性与有效性。 相似文献
5.
6.
基于离散伴随方法的透平叶栅气动优化设计 总被引:1,自引:0,他引:1
本文研究并给出了基于离散伴随理论和自动微分技术构建离散伴随系统的方法、伴随系统的求解策略以及基于离散伴随方法的透平叶栅气动优化设计流程,建立了相应的优化设计系统。利用该优化系统在无黏环境下,以叶栅通道进出口的熵增率为目标函数、以叶栅通道内的质量流量为约束,对某二维跨音速透平叶栅进行了气动优化设计。与优化前相比,优化后透平叶栅进出口熵增率减少8.82%,质量流量变化幅度小于0.003%。优化结果表明,本文提出的优化系统能够有效改善透平叶栅的气动优化性能,验证了本文提出的基于离散伴随方法的透平叶栅气动优化设计方法的正确性与有效性。 相似文献
7.
8.
本文给出了一个模拟叶栅内准三维定常和非定常粘性流动的数值方法。对于定常流动,采用TVD Lax-Wendroff格式和代数湍流模型求解雷诺平均Navier-Stokes方程,使用当地时间步长和多网格技术使计算加速收敛到定常状态;对于非定常流动,使用双时间步长和全隐式离散,采用与求解定常流动相似的多网格方法求解隐式离散方程。文中给出了VKI透平叶栅内的定常流结果和1.5级透平叶栅内的非定常数值结果。 相似文献
9.
通常的叶轮机械三维反方法存在以下问题:与使用者的经验相关;难以考虑多叶排之间的气动匹配;不能保证取得最优解等。本文创新性地将反方法与伴随方法相结合,充分利用伴随方法的计算时间与优化变量个数无关的特性,以期克服反方法的诸多问题,建立三维自动化的优化设计体系。本文首先推导了反方法的中弧线生成方程;在此基础上得到的Euler方程的伴随方法及其边界条件,中弧线生成方程的伴随方程及其边界条件;进一步地,本文开发了相应的设计体系;最后本文以亚琛1-1/2涡轮级为算例验证了本方法的有效性。 相似文献
10.
11.
12.
13.
《Revue Generale de Thermique》1997,36(8):625-634
The design and optimization of turbine blades submitted to high-temperature flows require the prediction of aerodynamic and thermal flow characteristics. A computation method for aerothermal viscous flows has been developed. The method is based on a compressible boundary layer approach. Tests were performed on turbine blade configurations. These tests include most difficulties that can be encountered in reality: laminar-turbulent transition, separation bubbles, strong accelerations, shock waves. Predictions of the wall heat transfer prove to be satisfactory. 相似文献
14.
In this paper we address the time-reversed simulation of viscous flows by the lattice Boltzmann method (LB). The theoretical derivation of the reversed LB from the Boltzmann equation is detailed, and the method implemented for weakly compressible flows using the D2Q9 scheme. The implementation of boundary conditions is also discussed. The accuracy and stability are illustrated by four test cases, namely the propagation of an acoustic wave in a medium at rest and in an uniform mean flow, the Taylor–Green vortex decay and the vortex pair–wall collision. 相似文献
15.
For the purpose of structure vibration reduction, a structural topology optimization for minimizing frequency response is proposed based on the level set method. The objective of the present study is to minimize the frequency response at the specified points or surfaces on the structure with an excitation frequency or a frequency range, subject to the given amount of the material over the admissible design domain. The sensitivity analysis with respect to the structural boundaries is carried out, while the Extended finite element method (X-FEM) is employed for solving the state equation and the adjoint equation. The optimal structure with smooth boundaries is obtained by the level set evolution with advection velocity, derived from the sensitivity analysis and the optimization algorithm. A number of numerical examples, in the frameworks of two-dimension (2D) and three-dimension (3D), are presented to demonstrate the feasibility and effectiveness of the proposed approach. 相似文献
16.
This paper presents a theoretical analysis of vibration control technology of wind turbine blades made of piezoelectric intelligent structures. The design of the blade structure, which is made from piezoelectric material, is
approximately equivalent to a flat shell structure. The differential equations of piezoelectric shallow shells for vibration control are derived based on piezoelectric laminated shell theory. On this basis, wind turbine blades are
simplified as elastic piezoelectric laminated shells. We establish the electromechanical coupling system dynamic model of intelligent structures and the dynamic equation of composite piezoelectric flat shell structures by analyzing
simulations of active vibration control. Simulation results show that, under wind load, blade vibration is reduced upon applying the control voltage. 相似文献
17.
This paper presents the fundamentals of a continuous adjoint method and the applications of this method to the aerodynamic design optimization of both external and internal flows.General formulation of the continuous adjoint equations and the corresponding boundary conditions are derived.With the adjoint method,the complete gradient information needed in the design optimization can be obtained by solving the governing flow equations and the corresponding adjoint equations only once for each cost function,regardless of the number of design parameters.An inverse design of airfoil is firstly performed to study the accuracy of the adjoint gradient and the effectiveness of the adjoint method as an inverse design method.Then the method is used to perform a series of single and multiple point design optimization problems involving the drag reduction of airfoil,wing,and wing-body configuration,and the aerodynamic performance improvement of turbine and compressor blade rows.The results demonstrate that the continuous adjoint method can efficiently and significantly improve the aerodynamic performance of the design in a shape optimization problem. 相似文献