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Publications associées (30)

Theoretical and Experimental Investigation of a Small-scale, High-speed, and Oil-free Radial Anode Off-gas Recirculation Fan for Solid Oxide Fuel Cell Systems

Jürg Alexander Schiffmann, Jan Van Herle, 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 ...

2020

Advanced design methods and non-ideal gas lubrication applied to aerodynamic bearings

Eliott Philippe Guenat

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 ...

EPFL2020

Can regional railway become emission-free with recently announced vehicles? - A case study of Bavaria

Michel Bierlaire, Nikola Obrenovic, Florian Mueller

Significant shares of regional passenger railway still rely on pollutive diesel vehicles. Alstom, Bombardier, Siemens, and Stadler have reacted and recently announced Battery Electric and Fuel Cell Electric Vehicles (BEVs and FCEVs). In this paper, we anal ...

2020

Pressure 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 ...

2020

Experimental Assessment of a 3D-Printed Stainless Steel Gas Foil Bearing

Jürg Alexander Schiffmann, Karim Magdi Zakaria Abdelrahman Shalash

Gas foil bearings (GFBs) are a key enabling technology for high-speed turbomachinery. The manufacturing of GFBs relies mainly on sheet metal forming techniques in order to conceive the compliant structure (e.g., bump foil) and the top foil. Such techniques ...

2020

An 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

Pressure is one of the constitutional quantities governing the flow field in gas lubricated bearings. Knowledge of the pressure is of principal importance in the fundamental understanding of such bearings and for the calibration of reduced order models. Th ...

2020

A Review of Grooved Dynamic Gas Bearings

Jürg Alexander Schiffmann, Eliott Philippe Guenat, Lili Gu

This paper offers an extensive review of publications dealing with the modeling, the design and the experimental investigation of grooved dynamic gas lubricated bearings. Recent years have witnessed a rise in small-scale and high-speed turbomachinery appli ...

2020

Scale limitations of gas bearing supported turbocompressors for vapor compression cycles

Jürg Alexander Schiffmann

An analysis of single-stage centrifugal compressors supported on dynamic, gas lubricated bearings for driving vapor compression cycles suggests that the maximum feasible compressor power is limited, primarily by the bearing load capacity, in the range from ...

2020

Flexure Pivot Oscillators for Mechanical Watches

Etienne Frédéric Gabriel Thalmann

It appears that the concerted efforts of the watchmaking industry are leading towards a limit in mechanical watch accuracy. The general consensus in horology is that the time base's quality factor, a dimensionless number that characterizes the oscillator d ...

EPFL2020

Reliable Frequency Regulation through Vehicle-to-Grid: Encoding Legislation with Robust Constraints

François Richard Vuille, Dirk Lauinger, Daniel Kuhn

Problem definition: Vehicle-to-grid increases the low utilization rate of privately owned electric vehicles by making their batteries available to electricity grids. We formulate a robust optimization problem that maximizes a vehicle owner’s expected profi ...

2024