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Publications associées (28)

Time scales of dynamic stall development on a vertical-axis wind turbine blade

Karen Ann J Mulleners, Sébastien Le Fouest, Daniel Marie Fernex

Vertical-axis wind turbines are excellent candidates to diversify wind energy technology, but their aerodynamic complexity limits industrial deployment. To improve the efficiency and lifespan of vertical-axis wind turbines, we desire data-driven models and ...

2023

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

Jürg Alexander Schiffmann, Soheyl Massoudi, Cyril Picard

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

Information-Driven Gas Distribution Mapping for Autonomous Mobile Robots

Alcherio Martinoli, Faezeh Rahbar, Chiara Ercolani

The ability to sense airborne pollutants with mobile robots provides a valuable asset for domains such as industrial safety and environmental monitoring. Oftentimes, this involves detecting how certain gases are spread out in the environment, commonly refe ...

MDPI2023

Real-time optimization of load sharing for gas compressors in the presence of uncertainty

Dominique Bonvin, Timm Faulwasser, Alejandro Gabriel Marchetti, Predrag Milosavljevic

This paper investigates the problem of load-sharing optimization of gas compressors in the presence of uncertainty. The objective is to operate a set of compressor units in an energy-efficient way, while at the same time meeting a varying load demand. The ...

ELSEVIER SCI LTD2020

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

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 ...

2020

Theoretical and Experimental Investigation of a 34 Watt Radial-Inflow Steam Turbine with Partial-Admission

Jan Van Herle, Jürg Alexander Schiffmann, Patrick Hubert Wagner

A micro steam turbine with a tip diameter of 15 mm was designed and experimentally characterized. At the nominal mass flow rate and total-to-total pressure ratio of 2.3 kg/h and 2, respectively, the turbine yields a power of 34 W and a total-to-static isen ...

2021

Theoretical and Experimental Investigation of a 34 Watt Radial-Inflow Steam Turbine with Partial-Admission

Jan Van Herle, Jürg Alexander Schiffmann, Patrick Hubert Wagner

A micro steam turbine with a tip diameter of 15mm was designed and experimentally characterized. At the nominal mass flow rate and total-to-total pressure ratio of 2.3 kgh-1 and 2, respectively, the turbine yields a power of 34W and a total-to-static isent ...

2021

Variable speed operation of centrifugal pumps running as turbines. Experimental investigation

François Avellan, João Nuno Gomes Borga Delgado

Pumps running as turbines are pointed out as a cost-effective solution for energy recovery in pressurised water supply systems. However, these hydraulic machines feature low efﬁciency under variable discharge operation due to the lack of an inlet ﬂow contr ...

Pergamon-Elsevier Science Ltd2019

Potential and Challenges of ORC driven Heat Pumps Based on Gas Bearing Supported Turbomachinery

Violette Mounier

Electrically Driven Heat Pumps (EDHPs) have been identified as a key technology to reduce the energy consumption in the domestic space heating sector. However, since EDHPs require electrical power, they face issues related to network overload at peak-time, ...

EPFL2018

Small, High-Speed, Oil-Free Radial Turbo-compressors for Cooling Applications: Refrigerant Selection

Jürg Alexander Schiffmann

Emerging energy-efficient, oil-free radial centrifugal compressors seem promising for small to mid-capacity air conditioning and refrigeration applications. Compressor design must balance trade-offs among impeller diameter, bearing type, and refrigerant se ...

2018

Real-Time Optimization of Interconnected Systems via Modifier Adaptation, with Application to Gas-Compressor Stations

Predrag Milosavljevic

The process industries are characterized by a large number of continuously operating plants, for which optimal operation is of economic and ecological importance. Many industrial systems can be regarded as an arrangement of several subsystems, where outp ...

EPFL2018

The Role of Impeller Outflow Conditions on the Performance of Vaned Diffusers

Jürg Alexander Schiffmann

Highly loaded impellers, typically used in turbocharger and gas turbine applications, exhaust an unsteady, transonic flow that is nonuniform across the span and pitch and swirling at angles approaching tangential. With the exception of the flow angle, conf ...

American Society of Mechanical Engineers2017

ORC Driven Heat Pump Running on Gas Bearings for Domestic Applications: Proof of Concept and Thermo-Economic Improvement Potential

Jürg Alexander Schiffmann, Violette Mounier

ORC driven Heat Pumps (HP-ORC) offer a promising technology of thermally driven heat pumps (TDHPs) for domestic applications. Recently, a 40 kW HP-ORC unit based on gas supported turbomachinery has been investigated in which the ORC radial turbine drives t ...

2017

Large Eddy Simulation of the Rotating Stall in a Pump-Turbine Operated in Pumping Mode at a Part-Load Condition

François Avellan, Olivier Pacot

The investigation of the rotating stall phenomenon appearing in the HYDRODYNA pump-turbine reduced scale model is carried out by performing a large-scale large eddy simulation (LES) computation using a mesh featuring approximately 85 x 10(6) elements. The ...

American Society of Mechanical Engineers2016

Experimental investigation of a two-stage oil-free domestic Air/Water heat pump prototype powered by an oil-free high-speed twin-stage radial compressor rotating on gas bearings

Daniel Favrat, Jürg Alexander Schiffmann, Jean-Baptiste Carré

Domestic heat pumps have been identified as a key-technology to decrease the energy consumption of the domestic sector, which represents 29% of the world final energy consumption. Space & water heating represent more than two third of the domestic sector e ...

2016

Modeling and Experimental Investigation of an Oil-Free Microcompressor-Turbine Unit for an Organic Rankine Cycle Driven Heat Pump

Jürg Alexander Schiffmann, Jonathan Demierre, Antonio Rubino

Domestic heating and cooling will more and more have to rely on heat pumps (HPs) in order to support a more rational use of primary energy consumption. The HP market is mainly dominated by electrically driven vapor compression cycles and by thermally drive ...

American Society of Mechanical Engineers2015

Mind the gap - tip leakage vortex in axial turbines

Mohamed Farhat, Matthieu Dreyer

The tendency of designing large Kaplan turbines with a continuous increase of output power is bringing to the front the cavitation erosion issue. Due to the flow in the gap between the runner and the discharge ring, axial turbine blades may develop the so ...

IOP Publishing2014

Fluid-Structure Coupling Effects on the Dynamic Response of Pump-Turbine Guide Vanes

Steven Roth

Hydraulic pump-turbines are subject to a high periodic excitation due to the Rotor-Stator Interaction, RSI. Basically, the RSI is caused by the impeller blade passage in the wake of the guide vanes in generating mode, or upstream from the guide vanes in pu ...

EPFL2012

Prototype of a thermally driven heat pump based on integrated Organic Rankine Cycles (ORC)

Daniel Favrat, Samuel Henchoz, Jonathan Demierre

The concept studied in this work is a low power ORC-ORC heat pump system (providing about 20 kW heat at the condenser) and that is composed of an ORC power cycle driving a reversed ORC heat pump cycle, both cycles using the same fluid. The centrifugal comp ...

2012

Hydrodynamics of a Pump-Turbine Operating at Off-Design Conditions in Generating Mode

Vlad Hasmatuchi

Modern pump-turbines are subject to frequent switching between the pumping and generating modes with extended operation under off-design conditions. Depending on the specific speed of the pump-turbine, the discharge-speed as well as torque-speed generating ...

EPFL2012