Numerical Study on the Influence of Gas Foil Thrust Bearings on the Vibrational Behavior

2018 ◽  
pp. 97-115
Author(s):  
Tomasz Pronobis ◽  
Alexander Ramin ◽  
Robert Liebich
Keyword(s):  
Numerical Study ◽  
Thrust Bearings ◽  
Vibrational Behavior

scholarly journals Numerical Analysis of Lift Generation in a Radial Segmented Gas Seal

2019 ◽  
Author(s):  
Mihai Arghir ◽  
Samia Dahite
Keyword(s):  
Numerical Analysis ◽  
Lift Force ◽  
Previous Analysis ◽  
Numerical Study ◽  
Rotor Speed ◽  
Rotating Shaft ◽  
Annular Ring ◽  
Thrust Bearings ◽  
Unsteady Problem ◽  
Face Seals

Abstract A radial segmented seal is composed of three or six carbon segments that are assembled by a circumferential (garter) spring that presses them against the rotor. Assembled, they take the form of an annular ring. Each segment has several pads that generate a radial lift force depending on the rotor speed. There are many ways of creating effective lift forces. For example, a pocket on the pad creates a lift force because each pad will act as a Rayleigh step bearing. A groove on the rotating shaft will also create a radial lift force on the pad. However, this latter lift force will be unsteady. The aim of the present work is the numerical study of the lift created by a grooved rotor on a pad. Due to the very small operating radial clearances of radial segmented seals (less than 10 μm), the problem can be simplified by analyzing a single pad and a grooved runner. Previous analysis of gas face seals or thrust bearings always considered grooved pads and a smooth runner, even when the runner was grooved. The peculiarity of this study, which is the first of its kind, is considering the unsteady problem of the moving runner grooves. The analysis was performed for a single pad of a radial segmented seal operating with air.

Numerical Study on the Improvement of the Hydrodynamic Behavior of Parallel Bearings by Surface Texturing

2012 ◽  
Author(s):  
Andrei Gherca ◽  
Patrick Maspeyrot ◽  
Mohamed Hajjam ◽  
Aurelian Fatu
Keyword(s):  
Review Paper ◽  
Numerical Study ◽  
Experimental Studies ◽  
Surface Texturing ◽  
Mechanical Seals ◽  
Hydrodynamic Behavior ◽  
Surface Textures ◽  
Thrust Bearings ◽  
Lubricated Contacts ◽  
Cavitation Phenomenon

Numerous experimental studies have already established the fact that surface texturing can successfully improve the hydrodynamic performances of lubricated contacts. In a 2005 review paper, Etsion [1] offered a synthesis of these works and showed that surface texturing can benefit a large variety of tribological applications such as mechanical seals, thrust bearings or piston rings. However, the physical interpretation of the effects induced by textures still represents a subject of debate within the tribological community. The earliest investigation with regard to surface textures dates back to the 1960’s and is attributed to Hamilton et al. [2]. The authors reported that the cavitation phenomenon induced by small irregularities is essential, as it allows high film pressures to overbalance low film pressures due to an antisymmetric pressure distribution.

scholarly journals Experiment and Numerical Study of Wear in Cross Roller Thrust Bearings

Lubricants ◽  
2015 ◽  
Vol 3 (2) ◽  
pp. 447-458 ◽  
Author(s):  
So Hwang ◽  
Na Lee ◽  
Naksoo Kim
Keyword(s):  
Numerical Study ◽  
Thrust Bearings

Numerical study of the low-frequency atomic dynamics in a Lennard-Jones glass

1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,
Keyword(s):  
Numerical Study ◽  
Low Frequency ◽  
Lennard Jones

Numerical simulation of the tree higro-thermal response in forest fire environment

2020 ◽  
pp. 57-65
Author(s):  
Eusébio Conceiçã ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Jorge Raposo ◽  
Domingos Xavier Viegas ◽  
...  
Keyword(s):  
Forest Fire ◽  
Numerical Study ◽  
Thermal Response ◽  
View Factor ◽  
Tree Model ◽  
Pine Tree ◽  
Surface Temperatures ◽  
Fire Environment ◽  
Fire Front ◽  
Heat Exchanges

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.

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