Moving from the current energy system mainly based on fossil fuels towards a more comprehensive use of renewable sources will take several decades. During this time and especially with the perspective of phasing out nuclear energy, a substantial proportion of electricity generation will continue to come from conventional technologies. Technological development in this area still offers considerable options for efficiency gains and emission reductions.
Specific objectives of the "combustion and gas turbine technologies" research field involve reliability, emissions, efficiency and profitability. The area covers both basic and applied issues of modern gas turbines and combustion technology. One aspect of the scientific work will facilitate the development of models, systems and measurement techniques for the best use of combustors and turbine systems. Particular emphasis lies in the creation of reliable system expertise for efficient and flexible-fuel power plant technology and, longer-term, the realisation of a hybrid power plant. These objectives are anchored in five different areas:
Work on reducing pollution focuses on the reduction of NOx emissions and soot. The aim of low emission combustion processes is the improvement of the physical and chemical models and their integration into "calculation codes" (namely, the DLR THETA code, commercial and customer codes). Kinetic reaction investigations are made in shock-wave tubes, laser-spectroscopic measurements are applied to generic combustion systems and testing installations to simulate technically relevant flame conditions (CBC-S).
Alternative fuels such as syngases and biogases are gaining in importance. A fundamental objective in this field is the study of the properties of these fuels. Without this knowledge, the technical use of these fuels is not possible. This includes studying the formation of pollutants in high pressure conditions. We use experimental techniques such as shock-wave tubes, laser spectroscopy and also probe measuring techniques. The resulting data is integrated into numerical models of combustion simulation.
Modern stationary gas turbines use lean premixed combustion as a means to reduce emissions. However, temporary instabilities can occur and cause vibrations in the combustion chamber. Methods of laser measurement technology and numerical simulation help to study these conditions and their impact on the gas turbine system.
Studies of flows and heat transfer are essential for the development of gas turbines. In this context, the development of measurement techniques and methods of numerical simulation is of great importance. In the field of turbines, profile aerodynamics and cooling are studied; aided by the development of automated optimisation methods for 3D geometrical design. Laser spectroscopy techniques allow the measurement of components and areas within the combustion chamber during actual operation. The data obtained serve as input to the modelling of the gas turbine system (TRACE).
Hybrid power plants:
The coupling of microgas turbines and fuel cells to a hybrid power plant is a promising model for a low-pollution and highly efficient power plant. In Stuttgart, a laboratory for the project hybrid power plant using a micro-turbine and fuel cell test was set up and is being used jointly by the Institute of Combustion Technology (VT) and the Institute of Technical Thermodynamics (TT). Special funds of the HGF enabled the constitution of a virtual institute and thus the incorporation of the Stuttgart University into the project. The objective of energy research at DLR in this area is to become a technology leader.