共查询到16条相似文献,搜索用时 156 毫秒
1.
透平叶栅三维粘性气动反问题的控制理论方法 总被引:2,自引:0,他引:2
将基于控制理论的形状优化设计方法应用于粘性可压流动条件下的透平叶栅三维气动反设计,详细推导了三维N-S方程伴随系统的偏微分方程组及其各类边界条件.讨论了伴随系统的解的适定性条件,并由此给出应用N-S方程进行气动优化的目标函数的选取限制.研究了伴随方程的数值求解技术,给出敏感性导数的最终计算式,结合拟牛顿算法发展了三维透平叶栅粘性反问题的气动设计方法. 相似文献
2.
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
3.
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
4.
5.
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
6.
7.
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
8.
9.
10.
11.
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
12.
A new method for shape optimization for unsteady viscous flows is presented. It is based on the continuous adjoint approach using a time accurate method and is capable of handling both inverse and direct objective functions. The objective function is minimized or maximized subject to the satisfaction of flow equations. The shape of the body is parametrized via a Non-Uniform Rational B-Splines (NURBS) curve and is updated by using the gradients obtained from solving the flow and adjoint equations. A finite element method based on streamline-upwind Petrov/Galerkin (SUPG) and pressure stabilized Petrov/Galerkin (PSPG) stabilization techniques is used to solve both the flow and adjoint equations. The method has been implemented and tested for the design of airfoils, based on enhancing its time-averaged aerodynamic coefficients. Interesting shapes are obtained, especially when the objective is to produce high performance airfoils. The effect of the extent of the window of time integration of flow and adjoint equations on the design process is studied. It is found that when the window of time integration is insufficient, the gradients are most likely to be erroneous. 相似文献
13.
气动/几何约束条件下翼型优化设计的最优控制理论方法 总被引:1,自引:0,他引:1
基于最优控制理论原理和Navier-Stokes方程,研究了气动/几何约束条件下多设计变量的翼型气动优化设计问题.根据给定的目标函数表达形式,在计算坐标下详细推导了相应的共轭方程及边界条件,以及梯度方程的具体数学形式.通过合理数学变换,得到了物理空间上适应于CFD数值求解的共轭方程直观表达形式,并发展了有效数值求解目的.通过将流动方程、共轭方程、目标函数敏感性导数和优化算法相结合,发展了一种新的气动优化设计目的.相关设计算例表明该目的在设计理论、适用性以及时间费用等方面具有显著特色和优点,且设计结果更为可靠. 相似文献
14.
多级轴流压气机三维数值优化设计 总被引:1,自引:0,他引:1
开发了利用非均匀有理B样条对叶轮机械三维叶片进行参数化重构的叶片造型模块和提供多种优化方法的优化模块;集成上述模块以及自主开发的网格生成软件和流场求解软件,建立了压气机气动数值优化平台.在该平台上对某5级轴流压气机末级静子进行了气动数值优化设计,取得了良好的优化效果,压气机性能得到有效提高. 相似文献
15.
16.
We present a new approach for the computation of shape sensitivities using the discrete adjoint and flow-sensitivity methods on Cartesian meshes with general polyhedral cells (cut-cells) at the wall boundaries. By directly linearizing geometric constructors of the cut-cells, an efficient and robust computation of shape sensitivities is achieved for problems governed by the Euler equations. The accuracy of the linearization is verified by the use of a model problem with an exact solution. Verification studies show that the convergence rate of gradients is second-order for design variables that do not alter the boundary shape, and is reduced to first-order for shape design problems. The approach is applied to several three-dimensional problems, including inverse design and shape optimization of a re-entry capsule in hypersonic flow. The results show that reliable approximations of the gradient are obtained in all cases. The approach is well-suited for geometry control via computer-aided design, and is especially effective for conceptual design studies with complex geometry where fast turn-around time is required. 相似文献