Development of novel turbo compressors for light gases
As part of a research project with CERN, novel methods and technologies are being investigated for the development of an energy- and cost-efficient cryogenic cycle for the Future Circular Collider (FCC), focusing on the limitations and possibilities of centrifugal compressor technology for operation with light gases. To this end, a closed-loop turbocompressor test rig was developed and commissioned at ITSM. This test rig consists of an ultra-high speed turbocompressor directly driven by a high power density motor and supported by gas bearings. The test stand has been designed to operate with air as well as with a whole range of nelium mixtures, i.e. from pure neon to pure helium. The performance of various compressor stages including shrouded and open impellers have been validated experimentally after a numerical optimisation of their aerodynamic performance. In addition, the coolant flowing through the engine at high power density provides the opportunity to study diabatic compression at different boundary conditions.
Robust Design of nozzle rings for radial turbines
The deposition of combustion residues in the nozzle ring can cause resonance excitation of rotor blades, which can lead to fatigue fracture. These externally excited blade vibrations are investigated numerically using detailed and simplified 3D flow simulations. The focus is on taking into account the fact that many different contamination patterns occur in reality, all of which can cause a different vibration excitation.
Novel stator concept for radial turbines
A novel concept for controlling the radial turbine of an exhaust gas turbocharger is being developed at ITSM. This concept, known as Multiple Exhaust Duct with Source Adjustment (MEDUSA), allows the operating point of the turbine to be controlled by partial admission of the rotor.The MEDUSA stator is divided into several segments around its circumference. When the mass flow is low, the inflow to individual segments can be closed, thus keeping the inflow to the turbine wheel in the open channels within the optimum range. Compared to conventional control systems, the required mechanics are mechanically very simple and therefore more robust.