CRC 1029 - TurbIn

Shockless Explosion Combustion
Shockless Explosion Combustion

Gas turbines provide about one fifth of the world wide power demand, with an upwards trend. Numerous efforts have been spent to achieve optimal efficiency. Still, only overall efficiencies of ca. 40% have been reached.

To cross this frontier is this project's goal. Its holistic view of the machine and the collaboration of numerous disciplines is what makes CRC 1029 stand out. The CRC is predominantly settled at Technische Universität Berlin.

One of our research interests is to replace the classical turbine's constant-pressure combustion with a more efficient constant-volume combustion. Contrary to a CI engine, a gas turbine has no contained combustion chamber; a different means to prevent the combusting gas from expansion must therefore be invoked. A dynamic approximation to this mode of operation can be achieved through detonative combustion. The strong pressure waves associated with detonations do however lead to short life spans and high maintenance efforts. An alternative is the controlled, homogeneous auto-ignition of the fuel.

At Freie Universität we are investigating the theoretical requirements for this mode of operation. We aim to identify the characteristic quantities and to develop a reduced process model. In close collaboration with the Institut für Strömungsmechanik und Technische Akustik at Technische Universität Berlin and the Institut für Technische Verbrennung at RWTH Aachen and using our results, we constantly improve the estimates and requirements on the fuel and on a planned demonstrator.

The process' simulation is the second focus of our research at Freie Universität. To correctly simulate the auto-ignition, detailed chemical kinetics must be coupled with the compressible gas equations. Close to auto-ignition temperature, these equations are very stiff, so their simulation is a numerical challenge. We tailor a specialized algorithm.