Numerical and Experimental Analyses of the Dynamic Characteristics of Journal Bearings With Square Dimples
Numerical and Experimental Analyses of the Dynamic Characteristics of Journal Bearings With Square Dimples
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DOI：
10.1115/1.4037151
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发表时间：
2018
影响因子：
2.5
通讯作者：
Hiroyuki Yamada;H. Taura;S. Kaneko
中科院分区：
文献类型：
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作者：
Hiroyuki Yamada;H. Taura;S. Kaneko
许多先前的数值研究已经研究了表面纹理对滑动轴承静态特性的影响，包括其承载能力和摩擦力矩。一般来说，滑动轴承的动态特性也很重要，因为它们是预测由滑动轴承支撑的实际转子振动行为的基本因素。然而，表面织构对这些动态特性的影响尚未通过数值或实验分析进行研究。因此，在本研究中，对纹理滑动轴承的动态特性进行了分析，例如它们的油膜动态系数和轴承支撑的稳定阈值轴转速。采用考虑惯性效应和能量损失的模型进行了数值分析；该模型与我们之前研究的静态特性实验结果吻合较好。采用均匀方窝纹理滑动轴承，采用正弦激励法进行了动态试验，验证了数值分析结果与实验结果的一致性，验证了数值分析的有效性。这些结果表明，在相同的工作条件下，纹理化对动力系数的主要影响是产生比光滑表面的常规交叉耦合刚度系数绝对值更低的刚度系数。纹理滑动轴承支撑转子的线性稳定阈值轴速高于光滑轴承，这主要是由于交叉耦合刚度系数的降低。这种趋势在高雷诺数操作条件和具有大量韧窝的纹理轴承中变得更加明显。
Numerous previous numerical studies have investigated the effect of surface texturing upon the static characteristics of journal bearings, including their load-carrying capacity and friction torque. In general, the dynamic characteristics of journal bearings are also important, since they are essential factors in predicting the vibration behavior of actual rotors supported by journal bearings. However, the effects of surface texture upon these dynamic characteristics have not been investigated through either numerical or experimental analysis. Thus, in the present study, such analyses were conducted to investigate the dynamic characteristics of textured journal bearings, such as their dynamic coefficients of oil film and the stability-threshold shaft speed supported by the bearings. Numerical analysis was done using a model that included inertial effects and energy loss; this model agreed well with experimental results concerning static characteristics from our previous study. Dynamic testing based on a sinusoidal-excitation method was also performed using textured journal bearings with uniform square dimples to verify the numerical results, which agreed qualitatively with those of experiment, confirming the validity of the numerical analysis. These results suggest that under the same operating conditions, the main effect of texturing upon the dynamic coefficients is to yield the cross-coupled stiffness coefficients with lower absolute values than the conventional ones with a smooth surface. The linear stability-threshold shaft speed of the rotor supported by the textured journal bearings became higher than that of a smooth bearing, mainly due to the reduction of cross-coupled stiffness coefficients. This tendency became more pronounced for high Reynolds number operating conditions and textured bearings with a large number of dimples.