Publications by Jürg Alexander Schiffmann

Dimensionless Group-Driven Ensemble Neural Networks for Robust Design Optimisation in Engineering

Jürg Alexander Schiffmann, Soheyl Massoudi

This work aims to develop a scalable surrogate modelling framework for robust multidisciplinary design optimisation (RMDO) in complex engineering systems. Focusing on gas-bearing supported rotors, it addresses the need to maintain system performance under ...

Oxford University Press (OUP)2025

Experimentally validated pre-design maps and performance estimation methods for small-scale turbopumps for organic rankine cycles

Jürg Alexander Schiffmann, Sajjad Zakeralhoseini

The organic Rankine cycle (ORC) system is considered a promising technology to exploit thermodynamic potential of waste heat. Small-scale ORC applications, including both vehicular applications and stationary power plants, would greatly benefit from more c ...

Global Power and Propulsion Society2025

DARTS-NETGAB: Design Automation and Real-Time Simulation Using Neural Network Ensembles for Turbocompressors on Gas-Bearings

Jürg Alexander Schiffmann, Soheyl Massoudi

DARTS-NETGAB is a unified framework for real-time simulation and automated design of gas-bearing supported turbocompressors, facilitating efficient transition from optimization to manufacturable designs. The framework integrates ensemble artificial neural ...

ASME International2025

Robust design optimization of gas-lubricated herringbone grooved journal bearings: Surrogate modeling and experimental validation

Jürg Alexander Schiffmann, Soheyl Massoudi

This study experimentally validates robust designs for herringbone grooved journal bearings (HGJBs) in micro-turbocompressors, addressing manufacturing deviations that lead to rotor instabilities. Experiments on a Pelton-driven rotor system focused on maxi ...

2025

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 ...

2023

DARTS-NETGAB: DESIGN AUTOMATION AND REAL-TIME SIMULATION USING NEURAL NETWORKS ENSEMBLES FOR TURBOCOMPRESSORS ON GAS-BEARINGS

Jürg Alexander Schiffmann, Soheyl Massoudi

In the domain of engineering design, where efficiency in simulation and precision in modeling are paramount, this study introduces DARTS-NETGAB, a pioneering platform uniquely designed for real-time simulation and automated design. Specifically tailored fo ...

American Society of Mechanical Engineers (ASME)2024

A High-Temperature, High-Speed, Oil-Free Syngas Compressor for Small-Scale Combined Heat and Power

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

For low-emission, small-scale combined heat and power generation, integrating a biomass gasifier with a downstream solid oxide fuel cell system is very promising due to their similar operating conditions in terms of temperatures and pressures. This match a ...

American Society of Mechanical Engineers2024

Small-scale turbopumps for waste heat recovery applications based on an organic Rankine cycle, modeling, analytical and experimental investigations

Jürg Alexander Schiffmann, Sajjad Zakeralhoseini

The organic Rankine cycle (ORC) system is considered a promising technology to exploit thermodynamic potential of waste heat. The weight and size of standard pumps can penalize the benefits of installing an ORC system on vehicles. Small-scale ORC applicati ...

EUS Editorial Universidad de Sevilla2024

A High-Temperature, High-Speed, Oil-Free Syngas Compressor for Small-Scale Combined Heat and Power

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

For low-emission, small-scale combined heat and power generation, integrating a biomass gasifier with a downstream solid oxide fuel cell system is very promising due to their similar operating conditions in terms of temperatures and pressures. This match a ...

2024

PARATURBOCAD: AUTOMATED PARAMETRIC GEOMETRY CONSTRUCTION FOR GAS-BEARING SUPPORTED TURBOCOMPRESSOR DESIGN WITH PYTHON

Jürg Alexander Schiffmann, Soheyl Massoudi

This research introduces an automated methodology for visualizing gas-bearing supported turbocompressor designs utilizing CadQuery 2, a scripting Computer-Aided Design (CAD) platform. This innovative approach simplifies the traditional design process, whic ...

American Society of Mechanical Engineers (ASME)2024

A High-Speed, High-Temperature, Micro-Cantilever Steam Turbine for Hot Syngas Compression in Small-Scale Combined Heat and Power

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

Coupling a biomass gasifier with a solid oxide fuel cell system through a high-temperature syngas compressor holds great promise to achieve low-emission, small-scale combined heat and power, since it reduces the number of heat exchangers and increases the ...

ASME International2024

An Integrated Approach to Designing Robust Gas-Bearing Supported Turbocompressors through Surrogate Modeling and Constrained All-At-Once Multi-Objective Optimization

Jürg Alexander Schiffmann, Cyril Picard, Soheyl Massoudi

This research introduces an innovative framework to engineering design to tackle the challenges of robustness against manufacturing deviations and holistic optimization simultaneously in a multi-disciplinary, multi-subsystems context. The methodology is ba ...

ASME International2024

A High-Speed, High-Temperature Micro-Cantilever Steam Turbine for Hot Syngas Compression in Small-Scale Combined Heat and Power

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

Coupling a biomass gasifier with a solid oxide fuel cell system through a high-temperature syngas compressor holds great promise to achieve low-emission, small-scale combined heat and power, since it reduces the number of heat exchangers and increases the ...

American Society of Mechanical Engineers2024

NMPC in Haptic Shared Control Steering: Optimizing Vehicle Motion

Jürg Alexander Schiffmann

As vehicles become more automated in the pursuit of comfort and safety, the human-machine interface must adapt to accommodate the intent of both driver and automation. The concept of haptic shared control steering allows lateral control of the vehicle to b ...

Elsevier B.V.2024

The Haptic Link Enabling Driver-Automation Teaming

Robert Fuchs, Jürg Alexander Schiffmann, Tomohiro Nakade

Over-reliance on the automation of transportation systems is understood to be the cause of new types of accidents. In this paper, the automated driving system is augmented with control methods enabling driver intervention without its full deactivation. The ...

IEEE2024

The influence of splitter blades and meridional profiles on the performance of small-scale turbopumps for ORC applications; analysis, neural network modeling and optimization

Jürg Alexander Schiffmann, Sajjad Zakeralhoseini

This work presents the influence of splitters on the performance of small-scale turbopumps for organic Rankine cycle applications numerically. Different design parameters, such as impeller diameter at the outlet, number of blades, blade angle at the traili ...

2023

Towards a real-time capable hybrid-twin for gas-bearing supported high-speed turbocompressors

Jürg Alexander Schiffmann, Luis Eric Olmedo Ocampo

A hybrid-twin for gas-bearing supported, high-speed turbocompressor is suggested to be an aide to increase the operational reliability and to provide valuable insights to improve its design. The bearing clearances of a few micrometers imply that excessive ...

2023

Brine-to-water heat pump test system for small-scale oil-free turbo compressors

Jürg Alexander Schiffmann

Hermetic, small-scale turbo compressors supported on gas-lubricated bearings and driven by high-speed electric motors represent a promising technology to increase the efficiency of domestic heat pumps and air conditioners. Moreover, thanks to the oil-free ...

Int Inst Refrigeration2023

Design and experimental investigation of a herringbone grooved gas bearing supported turbocharger

Jürg Alexander Schiffmann, Wanhui Liu

The design of an oil free turbocharger supported on herringbone grooved gas bearing was formulated as a multi-objective problem, which was solved by coupling a reduced order parametric model for gas bearing supported rotors with an evolutionary algorithm. ...

2023

An Integrated Approach to Designing Robust Turbocompressors on Gas Bearings Through Surrogate Modeling and Constrained Multi-Objective Optimization

Jürg Alexander Schiffmann, Cyril Picard, Soheyl Massoudi

Designing turbocompressors is a complex and challenging task, as it involves balancing conflicting objectives such as efficiency, stability, and robustness against manufacturing deviations. This paper proposes an integrated design methodology for turbocomp ...

ASME Amer Soc Mechanical Engineers2023