Publication
The Role of Impeller Outflow Conditions on the Performance of Vaned Diffusers
Publications associées (54)
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 ...
2023Aerodynamic study of a Hyperloop pod equipped with compressor to overcome the Kantrowitz limit
This paper describes an investigation of the aerodynamic performance of a Hyperloop pod equipped with an axial compressor using CFD simulation. The compressor is expected to reduce the drag if the operational speed of the pod exceeds the Kantrowitz Limit ( ...
2021The Role of Reynolds Number Effect and Tip Leakage in Compressor Geometry Scaling at Low Turbulent Reynolds Numbers
Jürg Alexander Schiffmann, Markus Diehl, Christoph Schreiber
In compressor design, a convenient way to save time is to scale an existing geometry to required specifications, rather than developing a new design. The approach works well when scaling compressors of similar size at high Reynolds numbers but becomes more ...
2020Analysis of Spiral-Grooved Gas Journal Bearings by the Narrow-Groove Theory and the Finite Element Method At Large Eccentricities
Jürg Alexander Schiffmann, Eliott Philippe Guenat, Elia Iseli
A finite groove approach (FGA), based on the finite element method (FEM), is used for analyzing the static and dynamic behavior of spiral-grooved aerodynamic journal bearings at different eccentricities, number of grooves, and compressibility numbers. The ...
2020Unsteady Flow Numerical Simulations on Internal Energy Dissipation for a Low-Head Centrifugal Pump at Part-Load Operating Conditions
François Avellan, Xiaoran Zhao
Dredge pumps are usually operated at part-load conditions, in which the low-solidity centrifugal impeller could experience large internal energy dissipation, related to flow separation and vortices. In this study, SST k- and SAS-SST turbulence models were ...
2019Comparative study between Cubic and Ellipsoidal Fokker-Planck kinetic models
Motivated by improving the performance of particle-based Monte-Carlo simulations in the transitional regime, Fokker–Planck kinetic models have been devised and studied as approximations of the Boltzmann collision operator. By generalizing the linear drift ...
2019Spatially Sampled Pressure Profile Measurements in Externally Pressurized Gas Journal Bearings
Jürg Alexander Schiffmann, Eliott Philippe Guenat, Karim Magdi Zakaria Abdelrahman Shalash
Externally pressurized gas journal bearings (EPGJB) are widely adopted to support high speed rotors. This paper presents novel experimental benchmark test data which enables EPGJB model validation. Axial and circumferential pressure profile measurements ar ...
2018ORC 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 ...
2017Flow control of weakly non-parallel flows: application to trailing vortices
François Gallaire, Giacomo Valerio Iungo, Francesco Viola, Erica Pezzica
A general formulation is proposed to control the integral amplification factor of harmonic disturbances in weakly non-parallel amplifier flows. The sensitivity of the local spatial stability spectrum to a base-flow modification is first determined, general ...
Cambridge Univ Press2017Rapid Production of Submicron Drug Substance Particles by Supersonic Spray Drying
Many newly developed active pharmaceutical ingredients (APIs) are poorly soluble in water and thus have a dissolution-limited bioavailability. The bioavailability of Biopharmaceutical Classification System (BCS) class II APIs increases if they dissolve fas ...
Amer Chemical Soc2017