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Jürg Alexander Schiffmann

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Publications associées (112)

Readiness evaluation of SOFC-MGT hybrid systems with carbon capture for distributed combined heat and power

Jürg Alexander Schiffmann, Jan Van Herle, Michele Gaffuri, Victoria Xu Hong He

The aggravation of climate change calls for the timely development and implementation of highly efficient, renewable, zero- or negative-emission energy solutions with high technological readiness and feasibility levels. Solid oxide fuel cells (SOFC) consti ...

Elsevier2023

Haptics based multi-level collaborative steering control for automated driving

Robert Fuchs, Jürg Alexander Schiffmann, Hannes Bleuler, Tomohiro Nakade

Increasing the capability of automated driving vehicles is motivated by environmental, productivity, and traffic safety benefits. But over-reliance on the automation system is known to cause accidents. The role of the driver cannot be underestimated as it ...

2023

Parametric Reduced Order Model of a Gas Bearings Supported Rotor

Jürg Alexander Schiffmann, Fabio Nobile, Dimitri Maurice Goutaudier

Gas bearings use pressurized gas as a lubricant to support and guide rotating machinery. These bearings have a number of advantages over traditional lubricated bearings, including higher efficiency in a variety of applications and reduced maintenance requi ...

Amer Soc Mechanical Engineers2023

Robust Design of Herringbone Grooved Journal Bearings using Multi-Objective Optimization with Artificial Neural Networks

Jürg Alexander Schiffmann, Soheyl Massoudi

Herringbone grooved journal bearings (HGJBs) are widely used in micro-turbocompressor applications due to their high load-carrying capacity, low friction, and oil-free solution. However, the performance of these bearings is sensitive to manufacturing devia ...

2023

Thermal management for gas lubricated, high-speed turbomachinery

Jürg Alexander Schiffmann, Luis Eric Olmedo Ocampo, Wei Liu, Wanhui Liu

High-speed turbomachinery is commonly designed to achieve high power densities. Limited space for active cooling results in a challenging thermal management. A thermal modeling approach leveraging modern declarative programming capabilities is presented, y ...

2023

Design, computational and experimental investigation of a small-scale turbopump for organic Rankine cycle systems

Jürg Alexander Schiffmann, Sajjad Zakeralhoseini

The hydraulic design, computational analysis, and experimental investigations of a high-speed small-scale turbopump for mobile waste heat recovery applications based on organic Rankine cycle systems are presented in this paper. Such applications demand hig ...

Elsevier2023

Robust Design of Herringbone Grooved Journal Bearings using Multi-Objective Optimization with Artificial Neural Networks

Jürg Alexander Schiffmann, Soheyl Massoudi

Amer Soc Mechanical Engineers2023

A new method to interpolate POD reduced bases-Application to the parametric model order reduction of a gas bearings supported rotor

Jürg Alexander Schiffmann, Fabio Nobile, Dimitri Maurice Goutaudier

The proper orthogonal decomposition (POD) is successfully employed in a variety of projection-based methods for parametric model order reduction (pMOR) of large dynamical systems. It extracts the most energetic modes describing the dynamics of a system fro ...

Wiley2023

Dated: Guidelines for Creating Synthetic Datasets for Engineering Design Applications

Jürg Alexander Schiffmann, Cyril Picard, Faez Ahmed

Exploiting the recent advancements in artificial intelligence, showcased by ChatGPT and DALL-E, in real-world applications necessitates vast, domain-specific, and publicly accessible datasets. Unfortunately, the scarcity of such datasets poses a significan ...

Amer Soc Mechanical Engineers2023

Unstable tilting motion of flexibly supported gas bearing bushings

Jürg Alexander Schiffmann, Philipp Kaspar Bättig

This paper presents measurements of the motion amplitudes from flexibly supported Herringbone Grooved Journal Bearing bushings. Measurements taken in four locations on the flexibly supported bearing bushing enable the distinction between the radial and the ...

2022

Experimental Investigation of Enhanced Grooves for Herringbone Grooved Journal Bearings

Jürg Alexander Schiffmann, Patrick Hubert Wagner, Philipp Kaspar Bättig

This paper presents the results of a theoretical and experimental investigation of the potential of enhanced groove geometries to increase the bearing clearance of a Herringbone Grooved Journal Bearing (HGJB) supported rotor. The theoretical study investig ...

2022

Adiabatic two-phase pressure drop of carbon dioxide in different channel orientations

Jürg Alexander Schiffmann, Rémi Revellin, David Schmid

Adiabatic pressure drop measurements of two-phase Carbon Dioxide (CO2) have been carried out in horizontal, vertical upward and downward direction with a dedicated test facility at the European Organization for Nuclear Research (CERN). A database of more t ...

2022

Heat transfer of flow boiling carbon dioxide in vertical upward direction

Jürg Alexander Schiffmann, Rémi Revellin, David Schmid

Heat transfer measurements of flow boiling Carbon Dioxide (CO2) in vertical upward direction have been carried out with a dedicated test facility at the European Organization for Nuclear Research (CERN). The experiments have been conducted in a vertical up ...

2022

Efficient steam generation in industry - Combined heat pump cycle with mechanical vapor recompression

Jürg Alexander Schiffmann, Luis Eric Olmedo Ocampo

Replacing fossil fuels with alternative energy sources for steam production in industry can help fulfill the targets towards a more sustainable energy landscape. In this work, a high-temperature heat pump and a gas-bearing supported turbocompressor are com ...

Int Inst Refrigeration2022

Analysis and modeling of the tip leakage flow on the performance of small-scale turbopumps for ORC applications

Jürg Alexander Schiffmann, Sajjad Zakeralhoseini

In this paper, the influence of tip clearance on the performance of small-scale turbopumps is studied numerically on extensive parameter ranges suitable for organic Rankine cycle applications. A novel and fully parameterized design model is developed and u ...

2022

Which professional skills do students learn in engineering team-based projects?

Jürg Alexander Schiffmann, Cyril Picard, Roland John Tormey, Cécile Hardebolle

Engineering accreditation bodies express a strong consensus that in addition to technical and scientific skills, engineering education also needs to promote the development of professional skills. In general, team-based projects are considered to be valuab ...

2022

Flow pattern observations and flow pattern map for adiabatic two-phase flow of carbon dioxide in vertical upward and downward direction

Jürg Alexander Schiffmann, Rémi Revellin, David Schmid

A test facility to investigate flow pattern transitions of vertical two-phase flow of CO2 has been built within the scope of the high-luminosity detector upgrades at the European Organization for Nuclear Research (CERN). Adiabatic flow pattern observations ...

2022

Robust design using multiobjective optimisation and artificial neural networks with application to a heat pump radial compressor

Jürg Alexander Schiffmann, Cyril Picard, Soheyl Massoudi

Although robustness is an important consideration to guarantee the performance of designs under deviation, systems are often engineered by evaluating their performance exclusively at nominal conditions. Robustness is sometimes evaluated a posteriori throug ...

2022

Experimental and numerical investigation of the unbalance behavior of rigid rotors supported by spiral-grooved gas journal bearings

Jürg Alexander Schiffmann, Elia Iseli

The forced response of rigid rotors, supported by herringbone-grooved gas journal bearings are investigated numerically and experimentally. The rotor configurations are varied by using end cylinders, attached at both sides of the shaft. Three rotors with d ...

ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD2022

Stability 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 ...

2021

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