Coupling of hydrodynamics and FEM with the CADFEM Extension Tribo-X inside Ansys for simulation and optimization of journal bearing shafts.
Tribo-X inside Ansys – efficient simulation of hydrodynamic journal bearings
Whether calculating bearing coefficients, bearing deformations, mixed frictions or cavitation – with Tribo-X inside Ansys, the behavior of journal bearing shafts is comprehensively represented in all its complexity. Determining the optimal dimensioning of bearings and rotors takes no time at all with Tribo-X and can be visualized directly on the CAD model in Ansys Mechanical.
Highlights at a glance
- Complete integration of journal bearing with Tribo-X in Ansys Workbench
- Short run times despite the high level of detail
- Taking into account elastic deformations of the bearing (EHD) and their effects on the gap geometry
- Complete representation of the Stribeck curve by taking surface roughnesses into account
- Identification of speed- and load-dependent bearing coefficients for further rotor dynamics analyses
- Simple execution of parameter studies though full parametric workflow
Dr. Paul Lethbridge
Entwicklungsingenieur, ANDRITZ AG
For our applications mainly water lubricated hydrodynamic plain bearings are used. These are often show a turbulent flow in the lubrication gap of the bearing. Therefore, it is important for us to consider such phenomena in the plain bearing simulation. What I particularly like about Tribo-X inside ANSYS is the simple usability and the short response time for a plain bearing analysis. Thus, we are able to calculate different operating conditions in order to represent reality as much as possible.
Geschäftsführer, MET Motoren- und Energietechnik GmbH
Tribo-X has proven to be a practical tool for fast and efficient plain bearing simulation and optimization. We have already successfully applied it to bearings for large turbines, diesel engines and micropumps. By analyzing the pressure and lubrication film distribution, we can obtain an overview of the characteristics of the bearing with regard to its application and various operating points within a short time. Effects such as the elasticity of the bearing design or roughness effects can be integrated very easily. More complex questions such as the change of equilibrium states in bearing ovality could be analyzed. The software is very helpful for us in the evaluation of practically relevant details such as grooves or scrapings.
Tribo-X inside Ansys in Detail
Tribo-X inside Ansys – calculation of hydrodynamic journal bearings under variable operating conditions
The load capacity and service life of hydrodynamic journal bearings is determined by the optimal dimensioning of shaft, bearing and bearing housing. With Tribo-X inside Ansys, fast parameter studies can be carried out in minutes, or even seconds, in order to adapt the bearing design to the different applications.
- Simple and efficient simulation of the journal bearings with Tribo-X
- Higher level of detail of the CAD model with realistic visualization
- User-friendly navigation thanks to simple workflow
- Determination of own journal bearing coefficients for the rotor dynamics analysis
“Linear Rotor Dynamics” add-on module
With this module, the speed-dependent stiffness and damping coefficients of a journal bearing can be precisely calculated.
The vibration behavior of journal bearing rotors is influenced by the stiffness and damping properties of the bearing. The bearing properties depend heavily on the speed and operating load and contribute significantly to stable operation of the rotor. With this module, bearing coefficients can be determined for every operating mode and used for the subsequent rotor dynamics analysis in Ansys.
„Thermo“ Add-on module
With this module, the influence of temperature on the operating behavior of the plain bearing can be taken into account
Depending on the operating point, the temperature in the bearing also changes. This leads to locally varying viscosities of the lubricant and significantly influences the bearing behavior of the plain bearing. In addition to dimensioning, the bearing design also plays an important role in dissipating the heat generated. With the module, the temperature influence in the plain bearing is comprehensively taken into account and thus enables optimum thermal management.
“Mixed Friction” add-on module
With this module, a hydrodynamic bearing analysis can be carried out, taking into account the surface roughnesses of bearing and shaft.
There is no such thing as “smooth” surfaces in practice. Instead, hydrodynamic journal bearings go through the mixed friction area during start-up and shut-down processes, high loads and low viscosity. In this transition area, the surface roughness of bearing and shaft play an important role. With this module, the roughness is fully taken into account, which allows complete calculation of the Stribeck curve.
Seminars related to Tribo-X inside Ansys
These seminars aim at simulation engineers and designers who, as part of their product development work, are responsible for designing hydrodynamic journal bearings or determining speed-dependent bearing coefficients for assessing the vibration behavior of rotors.
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