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Publications associées (36)
Nonlinear study on a rigid rotor supported by herringbone grooved gas bearings: Theory and validation
Jürg Alexander Schiffmann, Patrick Hubert Wagner, Philipp Kaspar Bättig, Wanhui Liu
The nonlinear behavior of a rigid rotor supported by herringbone grooved journal gas bearings (HGJBs) was investigated in this study. The two-dimensional narrow groove theory (2D-NGT) was adopted to model the HGJBs. A set of integrated rotor-bearing state ...
2021Stability and Unbalance Analysis of Rigid Rotors Supported by Spiral Groove Bearings: Comparison of Different Approaches
Jürg Alexander Schiffmann, Elia Iseli
The dynamic behavior of spiral-grooved gas bearing supported four degrees-of-freedom (DOF) rotors is investigated by means of linearized bearing force coefficients and full time-integrated transient analysis. The transient method consists of a state-space ...
2021Lane changing and lane choice in a congested urban environment
The goal of this thesis is to analyze lane changes and lane choice in a congested urban envi- ronment. This is possible thanks to the pNEUMA dataset, a new trac dataset resulting from a eld experiment with 10 drones ying over the central district of Athen ...
2021Theoretical and Experimental Investigation of a Small-scale, High-speed, and Oil-free Radial Anode Off-gas Recirculation Fan for Solid Oxide Fuel Cell Systems
Jan Van Herle, Jürg Alexander Schiffmann, Patrick Hubert Wagner
The Laboratory for Applied Mechanical Design (LAMD) designed, manufactured, and experimentally tested a novel recirculation fan for a 10 kWe solid oxide fuel cell (SOFC). The fan uses oil-free bearings, more specifically herringbone-grooved journal and spi ...
2020Advanced design methods and non-ideal gas lubrication applied to aerodynamic bearings
Clean and energy-efficient turbomachinery are playing an increasingly important role in the decarbonization of heating systems, waste heat recovery and transportation, as the use of small-scale heat pumping and fuel cells spreads. Such machines typically e ...
EPFL2020Pressure Profile Measurements within The Gas Film of Journal Foil Bearings Using An Instrumented Rotor with Telemetry
Jürg Alexander Schiffmann, Karim Magdi Zakaria Abdelrahman Shalash
Foil bearings are strong candidates to support oil-free turbomachinery. Although foil bearings are a widely used technology, models describing their behavior are not validated using the film pressure, which is the fundamental variable of any fluid film bea ...
2020Design of Load-Bearing Systems for Open-Ended Downstream Reuse
This paper discusses the design of load-bearing systems for buildings with regard to their current lack of open-ended reusability. The reason for dismantling load-bearing systems today tends to be less related to material degradation than to a loss of func ...
2019Flexible support and enhanced groove geometries for gas lubricated bearings
Gas lubricated Herringbone-Grooved Journal Bearings (HGJB) are a promising solution to support high-speed rotors in oil-free turbo-machinery due to their compactness, relatively low losses, no need for lubrication and low wear.
Gas lubricated bearings, how ...
EPFL2019An Instrumented High-Speed Rotor With Embedded Telemetry For The Continuous Spatial Pressure Profile Measurement In Gas Lubricated Bearings: A Proof Of Concept
Jürg Alexander Schiffmann, Karim Magdi Zakaria Abdelrahman Shalash
Gas lubricated bearings are capable of supporting high speed rotors with satisfactory load capacities. Pressure is one of the constitutional quantities governing the flow field in gas lubricated bearings. Knowledge of the pressure is of principal importanc ...
Amer Soc Mechanical Engineers2019Pressure Profile Measurements Within The Gas Film Of Journal Foil Bearings Using An Instrumented Rotor With Telemetry
Jürg Alexander Schiffmann, Karim Magdi Zakaria Abdelrahman Shalash
Foil bearings are strong candidates to support oil -free turbomachinery. Although foil bearings are a widely used technology, models describing their behavior are not validated using the film pressure, which is the fundamental variable of any fluid film be ...
Amer Soc Mechanical Engineers2019