Thermal turbomachinery is a key technology in contemporary energy conversion systems, whether stationary or mobile. Modern machines work with novel energy sources and are often flexible in a wide range of operation. By systematically investigating selected areas, we produce research results that we incorporate into the development of current and future generations of turbomachinery. For this purpose, we use complex simulation tools, some of which were developed in-house, as well as test facilities with relevant operating parameters.
In the research area of aeromechanics, we are concerned with the interaction between structure and flow, which can lead to externally excited or self-excited vibrations. This research area is strongly interdisciplinary and combines the fields of structural dynamics, aerodynamics, thermodynamics and materials science.
Vibrations of turbomachinery components are undesirable, as they can lead to damage due to material fatigue or overload. Reliable turbomachinery operates as vibration-free as possible over the entire operating range. The challenge of calculating aeromechanically induced vibration amplitudes in a reliable manner is enormous. We use highly accurate and efficient simulation tools for this purpose, which have been validated using measurement data from relevant test cases.
Steam Turbines and Wet Steam
In the research area steam turbines and wet steam, we investigate flows in steam turbines, starting at single-phase conditions and high pressures up to two-phase flows at the cold end and at pressures of a few millibars.
The wet steam flow that occurs due to the two phases comes from spontaneous condensation of supercooled steam and leads to both additional losses and subsequent phenomena such as droplet deposition and erosion, which can be damaging to the structure. We have the necessary simulation tools, relevant experimental equipment and in-house developed measurement technology to explore the field of wet steam flow and to gain important knowledge for the design.
In the field of radial turbomachinery, phenomena are investigated which are characteristic of this type of machine - in contrast to axial turbomachinery. Radial turbomachines are used where robustness and power density play an important role. For example, radial compressors and radial turbines are used in small and medium-sized turbochargers.
We have unique test rigs on which we can measure individual radial machine components as well as entire turbochargers. Our measurement range for turbochargers extends from smaller automotive engines to large commercial vehicle applications.
In the field of diffuser flows, we investigate decelerated flows, such as those that can occur at the outlet of turbines or compressors. Diffusors play an important role here, since on the one hand they contribute to increasing the overall efficiency of plants, and on the other hand they represent the boundary condition for the last turbomachinery stage and thus influence its operation.
The flow in diffusers is very complex and characterized by vortices, detached regions and strong gradients. Reliable simulation results can only be obtained through correspondingly careful calculations, which we achieve using measurement data from specially designed validation test rigs.