Full text
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| Author(s): |
Douglas Jhon Ramos
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica |
| Defense date: | 2019-02-25 |
| Examining board members: |
Gregory Bregion Daniel;
Rodrigo Nicoletti;
Rogério Gonçalves dos Santos
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| Advisor: | Gregory Bregion Daniel |
| Abstract | |
This work aims to evaluate the influence of mass conservation effects of the hydrodynamic bearing on the dynamic response of the rotating system in which it is inserted. Thus, computational simulations were performed in order to evaluate the behavior of the bearing under static load and dynamic load conditions, to determine in which operational conditions of the rotating system the model with mass conservation become relevant for the analysis. The rotating system's model is constructed using the Finite Element Method (FEM), and the rotor is supported by hydrodynamic bearings, modeled by the Reynolds equation, whose solution was obtained through the Finite Volume Method (FVM). Two different approaches are used to model the bearing, the Gumbel condition being used for the analysis without cavitation and the Cavitation algorithm of Elrod for the analysis with cavitation. The first part of the analysis developed in this work refers to the static load condition, in which different cavitation models were compared (model of Gümbel (1914), Nowald et al. (2016), Ausas et al. (2007) and Elrod (1981)), in addition to the comparison between the locus of the model of Gümbel (1914) and Vijayaraghavan and Keith Jr. (1989). The second part of the analysis refers to the dynamic load condition, in which through nonlinear analysis, the bearing is inserted into the rotating system operating under different eccentricity ratios, unbalance levels, rotor asymmetry levels, rotational speed and the run-up condition. Through the simulations under the static load condition, it was observed that there are no significant differences between the model of Gümbel (1914) and Vijayaraghavan and Keith Jr. (1989). For the dynamic load condition, it was observed that the inclusion of mass conservation does not lead to significant changes in the dynamic response of the rotor under normal operating conditions. However, conditions near to the instability threshold show a significant difference in the dynamic response, since the model without mass conservation (Gümbel, 1914) reaches this limit before the model with mass conservation (Vijayaraghavan and Keith Jr., 1989) (AU) | |
| FAPESP's process: | 16/20975-4 - Effects of the cavitation in hydrodynamic bearings on the dynamic behavior of rotors |
| Grantee: | Douglas Jhon Ramos |
| Support Opportunities: | Scholarships in Brazil - Master |