“…Figure 1.Sketches of five typical vibration patterns often observed in TC run-ups. 6,13 Figure 2.Geometries of plain cylindrical and three-lobe FRBs: (a) a plain cylindrical FRB; (b) a three-lobe FRB. Note that both inner and outer clearances are enlarged to show details.…”
Section: Introductionmentioning
confidence: 99%
“…The nonlinear behaviours of TC rotor supported by plain cylindrical FRBs have been extensively discussed in previous literature. [1][2][3][4][5][6][7][8][9][10][11][12][13] Depending on the geometry of the TC rotor and on dimensions of the individual FRBs, five different patterns of nonlinear vibrations are often observed in TC run-ups, which are shown in Figure 1. Individual components present in the patterns can be briefly described as: (i) the synchronous (Syn, due to rotor imbalance); (ii) the 1 subsynchronous (Sub1, oil whirl/whip in the inner oil films excite the gyroscopic conical forward mode); (iii) the 2 subsynchronous (Sub2, oil whirl/whip in the inner oil films excite the gyroscopic translational forward mode); (iv) the 3 subsynchronous (Sub3, oil whirl/ whip in the outer oil films excite the gyroscopic conical forward mode); (v) total instability (TI, both inner and outer films are unstable).…”
Section: Introductionmentioning
confidence: 99%
“…Sketches of five typical vibration patterns often observed in TC run-ups. 6,13 based on the finite difference method (FDM) or the FEM are often used. The numerical methods are accurate, but they have large computational expenses, especially in the case of complex systems with more fluid films, a flexible rotor with a quite large number of degrees of freedom (DOF) and the demand of repeated calculations for parametric studies.…”
Floating-ring bearings are widely used in automotive turbocharger machinery because of their robustness, low cost and their suitability under extreme rotation speeds. This type of bearings, however, can become a source of noise due to oil whirl/whip instability. The stabilizing effect of lobed bearing shape is known in the literature, which encourages the researchers to substitute plain cylindrical full floating bearings with lobed geometries in their outer and inner clearances to prevent the rotor-bearing system from developing oil whirl/whip instability or to reduce its amplitude of response when oil whirl/whip instability takes place. In this study, a novel concept of a floating-ring bearing with three-lobed clearances in its inner and outer films is modelled. In order to perform transient simulations, a very time-efficient approximate solution for the Reynolds equation to the geometry of three-lobed bearings is presented. Using the run-up simulation method, the nonlinear dynamic behaviours of a real turbocharger rotor supported by the novel concept of three-lobed floating-ring bearings are systematically investigated. The newly obtained results show that the sub-synchronous vibrations can be thoroughly suppressed with high preload factor at the cost of a moderate increase in the synchronous vibrations. Hence, the three-lobed floating-ring bearings design is an attractive alternative to plain cylindrical floating-ring bearings for automotive turbocharger applications.
“…Figure 1.Sketches of five typical vibration patterns often observed in TC run-ups. 6,13 Figure 2.Geometries of plain cylindrical and three-lobe FRBs: (a) a plain cylindrical FRB; (b) a three-lobe FRB. Note that both inner and outer clearances are enlarged to show details.…”
Section: Introductionmentioning
confidence: 99%
“…The nonlinear behaviours of TC rotor supported by plain cylindrical FRBs have been extensively discussed in previous literature. [1][2][3][4][5][6][7][8][9][10][11][12][13] Depending on the geometry of the TC rotor and on dimensions of the individual FRBs, five different patterns of nonlinear vibrations are often observed in TC run-ups, which are shown in Figure 1. Individual components present in the patterns can be briefly described as: (i) the synchronous (Syn, due to rotor imbalance); (ii) the 1 subsynchronous (Sub1, oil whirl/whip in the inner oil films excite the gyroscopic conical forward mode); (iii) the 2 subsynchronous (Sub2, oil whirl/whip in the inner oil films excite the gyroscopic translational forward mode); (iv) the 3 subsynchronous (Sub3, oil whirl/ whip in the outer oil films excite the gyroscopic conical forward mode); (v) total instability (TI, both inner and outer films are unstable).…”
Section: Introductionmentioning
confidence: 99%
“…Sketches of five typical vibration patterns often observed in TC run-ups. 6,13 based on the finite difference method (FDM) or the FEM are often used. The numerical methods are accurate, but they have large computational expenses, especially in the case of complex systems with more fluid films, a flexible rotor with a quite large number of degrees of freedom (DOF) and the demand of repeated calculations for parametric studies.…”
Floating-ring bearings are widely used in automotive turbocharger machinery because of their robustness, low cost and their suitability under extreme rotation speeds. This type of bearings, however, can become a source of noise due to oil whirl/whip instability. The stabilizing effect of lobed bearing shape is known in the literature, which encourages the researchers to substitute plain cylindrical full floating bearings with lobed geometries in their outer and inner clearances to prevent the rotor-bearing system from developing oil whirl/whip instability or to reduce its amplitude of response when oil whirl/whip instability takes place. In this study, a novel concept of a floating-ring bearing with three-lobed clearances in its inner and outer films is modelled. In order to perform transient simulations, a very time-efficient approximate solution for the Reynolds equation to the geometry of three-lobed bearings is presented. Using the run-up simulation method, the nonlinear dynamic behaviours of a real turbocharger rotor supported by the novel concept of three-lobed floating-ring bearings are systematically investigated. The newly obtained results show that the sub-synchronous vibrations can be thoroughly suppressed with high preload factor at the cost of a moderate increase in the synchronous vibrations. Hence, the three-lobed floating-ring bearings design is an attractive alternative to plain cylindrical floating-ring bearings for automotive turbocharger applications.
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