On the Numerical Simulation of Nonlinear Transient Behavior of Compliant Air Foil Bearings
On the Numerical Simulation of Nonlinear Transient Behavior of Compliant Air Foil Bearings
复制标题
柔性空气箔片轴承非线性瞬态行为的数值模拟
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
I. Santos
中科院分区：
文献类型：
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作者：
J. S. Larsen;Bo Bjerregaard Nielsen;I. Santos
摘要柔性空气箔轴承（AFB）具有低摩擦和不需要外部润滑系统的特点，在高速机器的发展中具有根本的重要性，从而实现了更环保的设计。然而，由这种类型的轴承支撑的转子由于低水平的阻尼而对不平衡和非线性不稳定性更敏感。由AFB支撑的转子的瞬态非线性行为要求求解可压缩流体的雷诺方程，该方程与顶部/凸起箔片表面的顺应性以及该复杂柔性结构的部件之间的摩擦力相耦合。旋翼与空燃比相互作用的非线性瞬态仿真仍然是一个具有挑战性和非常耗时的任务。在假设压力随时间的变化dp/dt可忽略的特定情况下，可以相对安全地进行用于预测转子轴承瞬态行为的时间模拟，并且没有数值不稳定性问题。然而，处理非线性问题的精确和正确的方法是考虑压力随时间的变化，即dp/dt。在这个框架中，本文给出了一个原始的贡献，通过实施一种方法，在文献中提出的，其中的压力在时间上的变化dp/dt包括作为状态空间变量域的一部分。它被扩展到模拟工业AFB的瞬态和非线性行为，由三个独立的部分建成，并耦合到一个刚性转子中使用的西门子压缩机。一个有效的有限元模型先前开发的，用于离散化的压力场和箔顺应性结构。理论结果进行了验证，对文献和长期dp/dt的重要性仔细阐明。重点对转子-轴承系统的瞬态非线性行为进行了参数研究，并讨论了所提出的方法的效率，突出了优点和缺点。
Abstract Compliant Air Foil Bearings (AFB) have fundamental importance in the development of high speed machines due to low friction and no need of an external lubrication system, leading to a more environmental-friendly design. Nevertheless, rotors supported by such a type of bearing are more sensitive to unbalance and nonlinear instabilities due to low level of damping. The transient nonlinear behaviour of rotors supported by AFBs demands the solution of the Reynolds equation for compressible fluid coupled to the compliance of top/bump foil surfaces and the friction between parts of this complex flexible structure. The nonlinear transient simulation of rotors interacting with AFB is still a challenge and a very time-consuming task. In the particular case of assuming the variation of pressure in time dp/dt negligible, time simulations for predicting rotor-bearing transient behaviour can be carried out relatively safely and without numerical instability problems. Nevertheless, a precise and correct way of dealing with the nonlinear problem is taking into consideration the variation of pressure in time, i.e. dp/dt. In this framework, this paper gives an original contribution by implementing a method, as proposed in the literature, in which the variation of pressure in time dp/dt is included as part of the state space variable domain. It is extended to simulate the transient and nonlinear behaviour of an industrial AFB, built by three independent segments and coupled to a rigid rotor as used in a Siemens compressor. An efficient finite element model previously developed, is used for the discretisation of the pressure field and foil compliant structure. The theoretical results are validated against the literature and the importance of the term dp/dt is carefully elucidated. A parameter study with focus on the transient nonlinear behavior of the rotor-bearing system is carried out and the efficiency of the method presented is discussed, highlighting advantages and drawbacks.
箔空气轴承转子系统非线性动力学计算的有效技术
DOI：
10.1115/gt2013-94389
发表时间：
2013
期刊：
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影响因子：
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作者：
Pham H
通讯作者：
Pham H