时变磁场下径向电涡流阻尼器的动力特性

Dynamic Performance of a Radial Eddy Current Damper under Variable-time Magnetic Field

为了研究时变磁场和导体运动的组合效应对非旋转型径向电涡流阻尼器动力特性的影响,在一个径向电涡流阻尼器柔性转子系统上测量不同正弦激励磁场强度和频率条件下转子系统在恒速运行时的运动轨道以及在慢加速运动过程中的不平衡响应。结果说明正弦激励磁场的频率对径向电涡流阻尼器的动力特性有着显著的影响。随着正弦激励磁场频率的增大,径向电涡流阻尼器的减振能力迅速减小。对于给定的正弦激励磁场强度,存在着一个能够影响阻尼器特性的最大正弦激励磁场频率;而对于给定的正弦激励磁场频率,存在着一个能够影响阻尼器特性的最低正弦激励磁场强度。只要正弦激励磁场的频率小于最大正弦激励磁场频率或者正弦激励磁场的强度大于最低正弦激励磁场强度,径向电涡流阻尼器的特性同样可以用正弦激励磁场来控制,否则正弦激励磁场对径向电涡流阻尼器的特性几乎没有影响。按照转子动力学的观点,非时变磁场控制的径向电涡流阻尼器的动力特性优于时变磁场控制时的动力特性。

In order to study the combination effect of the variable-time magnetic field and the conductor motion on the dynamic behavior of a non-rotational radial eddy current damper, the rotor motion orbits at steady state rotational speeds and the rotor unbalance responses in the slowly accelerating operation at different sinusoidal magnetic flux densities and the magnetic field frequencies are experimentally studied on the flexible rotor system of a radial eddy current damper. It is shown that the frequency of sinusoidal magnetic field has a significant effect on the dynamic behavior of the radial eddy current damper. With the increase of frequency of sinusoidal magnetic field, the damping capability of radial eddy current damper decreases rapidly. There is a maximum frequency of sinusoidal magnetic field for a given magnetic field strength or a minimum strength of sinusoidal magnetic field for a given frequency of sinusoidal magnetic field to affect the dynamic behavior of the eddy current damper. If the frequency of sinusoidal magnetic field is less than the maximum frequency or the strength of sinusoidal magnetic field is over the minimum magnetic field strength, the dynamic behavior of the radial eddy current damper can also be controlled by application of an external sinusoidal magnetic field, otherwise the dynamic behavior of the radial eddy current damper is the same as that without exciting magnetic field. In the view of rotor dynamics, it is better to use invariable-time magnetic field instead of variable-time magnetic field to change the dynamic behavior of radial eddy current damper.