Brief description
More environmentally friendly flying is playing an increasingly important role in the public eye and is part of research worldwide. With the Flightpath 2050 targets, there is a concrete effort to reduce the environmental impact of aviation. In this context, the fuel cell is seen as a promising concept for the future.
As part of the doctoral thesis, the potential of a fuel cell hybrid drive for aviation was investigated. Various degrees of hybridization and flight missions were examined and evaluated in a multidisciplinary manner. The aim was to identify for which area of application and for which class of aircraft a fuel cell drive makes sense.
Project objectives
- Determination of the potential of a fuel cell (hybrid) drive for aviation
- Investigation of the mutual influences on the design of the fuel cell (hybrid) drive and the aircraft
- Identification of the optimum area of application for a fuel cell drive in aviation
Project partner: MTU Aero Engines
Researcher: Jonas Schroeter
Brief description
In this project, the new concept of so-called “hybrid blades” was developed and numerically tested. The hybrid blades should be used in the area of highly loaded axial compressor stages, in which conventional blade geometries can no longer guarantee efficient pressure build-up. The hybrid blade concept is a further development of the tandem blade, which eliminates the weak points of the lossy end-wall flow of tandems. The hybrid blades are used both as stators and as rotors in the chair's low-speed axial compressor “FRANCC” and tested numerically.
Project goals
- Development of a fully automated process chain for the design of hybrid blades.
- 3D optimization of hybrid blades with the aim of efficiently extending the operating range of the axial compressor.
- Gaining new insights into the secondary effects of the flow within the compressor stage using different hybrid rotors and hybrid stators.
- Derivation of design guidelines for hybrid blades.
Project partner: None
Researcher: Jannik Eckel
Brief description
The development of an aircraft engine is a complex and interdisciplinary process. The need for faster and more precise predictions means that a large number of dependencies must already be taken into account in the preliminary design phase. With the help of simplified and generalized physical laws, a method can be developed that achieves the desired level of detail in the design of the preliminary design phase. The mechanical design is an important step in the process and provides an initial component design layout based on parametric studies. Further disciplines can complement the results with an assessment of structural strength, a component-based weight estimate and an initial assessment of the component's service life. The great advantage of these methods is their flexibility, making it easier to develop new concepts independently of the knowledge-based designs. This project focused on the axial compressors and their interdependencies. For each main component of the compressor (blades, vanes, discs, casing), this project developed methods to parameterize the topology and developed structural aspects such as stresses, mechanical and manufacturing limits, low and high cycle fatigue, creep, disc burst and casing containment.
Project goals
- Development of multidisciplinary mechanical design methods for axial compressors
- Investigation of the impact of mechanical preliminary design methods during the preliminary design phase
Project partner: MTU Aero Engines AG
Reseacher: Ioannis Zaimis
Brief description
In times of strongly fluctuating feed-in of renewable electricity into the electrical grid, the need for control energy available at short notice is growing, which is why the use of agile gas turbine plants is becoming increasingly important. In order to achieve a fast start-up of the plant, it must be kept at aerodynamic partial load, which correlates with a reduction in process temperatures, pressures and geometric adjustments (e.g. guide vane adjustment). The changed conditions compared to the Aerodynamic Design Point (ADP) lead to the development of so-called “real geometry effects” in the annular channel (gaps, steps, edges, blade misalignment). The qualitative and quantitative assessment of these phenomena and their influence on turbine performance is the subject of current research.
Project objective
- Identification of decisive aerodynamic disturbance mechanisms on the performance of a highly loaded axial compressor
- Sensitivity study and potential analysis of desensitizing measures for a more robust compressor design
Project partners: Federal Ministry of Economics and Climate Protection, Rolls-Royce Deutschland Ltd & Co KG
Author: Jannik Petermann
Brief description
In order to reduce the environmental impact and improve the overall efficiency of an aircraft engine, thermal efficiency must be increased. The geared turbofan concept investigated by SAFRAN Aircraft Engines as part of CS2 aims to develop an extremely high efficiency engine architecture and ground test demonstrator in which increasing the core engine pressure ratio improves the thermal efficiency of the engine. However, a further increase in the core engine pressure ratio inevitably leads to a reduction in the size and cross-section of the core engine, which poses new challenges for the HPC design, especially for the rear compressor stages. Since the clearances between the rotor tips and the stator seals are absolutely limited to avoid friction, a reduction in blade height leads to larger relative blade clearances, which result in increased secondary flow phenomena, including stronger vortices at the blade tips, leakage flows at the shroud and increased boundary layer growth in the endwall regions.
These adverse aerodynamic effects impair the operating behavior (stall margin) and the aerodynamic performance (efficiency). To overcome the detrimental effects of pronounced leakage flows at the rotor tip, casing treatments (CT) are usually carried out. While CTs are known to enhance the flow in the rotor tip region, they usually result in a radial realignment of the flow and weaken the downstream compressor flow at lower span heights. This phenomenon will be particularly pronounced in the compact rear stages of future HPCs with high pressure ratios and low blade heights, and significantly increases the risk of premature stalling of the compressor due to weaker flow in the lower span region. To address these aerodynamic challenges, General Electric Deutschland (GEDE) is researching innovative HPC technologies including an advanced 3D blade design for HPC rear stages as part of the CS2 Joint Undertaking.
Project objectives
- To develop compressor flow treatment technologies that enhance full span flow, improve stability in a multi-stage compressor environment and maximize the potential of CT technology.
- The provision of a compressor test rig enabling validation of the HPC backstage technologies developed by GEDE and TUM-LTF, including detailed quantification of HPC performance and operability under representative engine conditions.
The development and application of advanced unsteady pressure and temperature measurements that enable time-accurate entropy estimation and thus provide a detailed understanding of the flow physics and aerodynamic loss mechanisms within the developed HPC backstage concept.
Project partner: GE
Project team: Christian Köhler, Christian Schäffer