• Project duration:
  10/2019 - 09/2022
• Funding:
  BMWi, MAN Energy Solution SE
• Funding code:
  03EE5013M
• Researcher:
  Federico Lo Presti, M. Sc.
• Project partner:
  MAN Energy Solution SE

Flexible operation of gas and steam turbines, for example connected to chemical energy storage systems (power-to-X, power-to-gas or power-to-liquid), requires reliable predictability of the dynamic behavior of the machines, especially during rapid load changes (start-stop cycles with shortened start-up times) and in case of unavoidable changes in the composition of locally available fuels.
The physical effects, such as thermoacoustic oscillations in the combustion chamber or inhomogeneous, transient thermal loads on the turbine blades that occur during predominantly transient operation, influence both the service life of the machines and their efficiency, which usually deviates considerably from the optimum value.
Transient operating conditions have a macroscopic effect on the topological development of the flow fields in the respective components (in the combustion chamber, for example, due to the transient heat release, in the turbine due to the increased instabilities of the boundary layers), which in turn massively influence the turbulent mixing processes at the interfaces between components (as in the case of the inlet to the high-pressure turbine, on the surface of the cooled blades and in the secondary spaces). The development and optimization of turbomachinery for the energy transition is increasingly supported by numerical fluid mechanics (CFD) analyses. Numerical modeling of the turbulent fields realized in turbomachinery requires, in principle, spectral separation of the characteristic length and time scales of turbulent flow as well as complete resolution of all degrees of freedom.
The research activities envisaged in the joint project address different, complementary scientific and technological issues relevant to the operation of turbomachinery in the innovative energy conversion systems. The overall objective of subproject 4.7 is to develop a hybrid modeling approach for numerical simulations of the unsteady, inhomogeneous flows in gas turbine components, taking into account the varying flow conditions (in terms of Mach and Reynolds numbers) as well as the properties of the medium during rapid load changes and, in particular, shortened start-up times. The knowledge gained from these numerical experiments will form the basis for the hybrid models that will support the optimization processes.