The efficient computation of the nonlinear dynamic response of a foil-air bearing rotor system
The efficient computation of the nonlinear dynamic response of a foil-air bearing rotor system
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DOI：
10.1016/j.jsv.2014.03.001
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发表时间：
2014-07-21
影响因子：
4.7
通讯作者：
Pham, H. M.
中科院分区：
文献类型：
--
作者：
Bonello, P.;Pham, H. M.
箔片空气轴承（FAB）使无油润滑成为可能。然而，其潜在的引入不良的非线性效应，需要一个可靠的手段来计算动态响应。迄今为止，通过简化来减轻计算负担，这些简化损害了转子、气膜和翼型结构之间动态相互作用的真实性质，从而引入了显著误差的可能性。这项研究的整体新颖的贡献是发展有效的算法，同时解决状态方程。使用两种替代变换提取方程：（i）有限差分（FD）;和（ii）一种新的任意阶Galerkin约简（GR），它不使用网格，大大减少了状态变量的数量。一个矢量化的配方有利于解决方案，在两种可选的方式：（i）在时域中的任意响应通过隐式积分使用现成的例程;和（ii）在频域中的自激周期响应的直接计算通过一种新的谐波平衡（HB）方法。GR和FD交叉验证的时域模拟，确认GR显着减少了计算时间。仿真还交叉验证了应用于参考FD模型的时域和频域解决方案，并证明了HB正确适应结构阻尼的独特能力。(C)2014爱思唯尔有限公司版权所有。
The foil-air bearing (FAB) enables the emergence of oil-free turbomachinery. However, its potential to introduce undesirable nonlinear effects necessitates a reliable means for calculating the dynamic response. The computational burden has hitherto been alleviated by simplifications that compromised the true nature of the dynamic interaction between the rotor, air film and foil structure, introducing the potential for significant error. The overall novel contribution of this research is the development of efficient algorithms for the simultaneous solution of the state equations. The equations are extracted using two alternative transformations: (i) Finite Difference (FD); and (ii) a novel arbitrary-order Galerkin Reduction (GR) which does not use a grid, considerably reducing the number of state variables. A vectorized formulation facilitates the solution in two alternative ways: (i) in the time domain for arbitrary response via implicit integration using readily available routines; and (ii) in the frequency domain for the direct computation of self-excited periodic response via a novel Harmonic Balance (HB) method. GR and FD are cross-verified by time domain simulations which confirm that GR significantly reduces the computation time. Simulations also cross-verify the time and frequency domain solutions applied to the reference FD model and demonstrate the unique ability of HB to correctly accommodate structural damping. (C) 2014 Elsevier Ltd. All rights reserved.