Blisk (one piece turbomachine combining blade and rotor disk in one piece) is a design concept that offers the potential of improving the efficiency of the turbomachine and reducing maintenance because of the elimination of the requirement to join blades to the disk.
The BliDes HDV project examined both production technologies and simulation methods. A tandem rotor and stator were developed to a complete tandem turbine stage. The design possibilities of Casing treatments were applied for improved Blisk performance. A Blisk was tested up to a temperature of 650°C, compared to previously attained temperatures of 500°C. Production processes for compressor Blisk forgings were developed and demonstrated material properties that fully complied with the materials requirements.
The aim of the BliDes HDV project is to make this technology accessible for practical use. For this reason, a real usage of a blisk will be simulated, including phenomena of air flow, tension and temperature. Risks regarding pipe and flutter should be minimized. A usage until 650°C should be possible. For the first time, it will be possible to use blisks in the rear parts of high-pressure compressors.
Further, there will be a development of the supply chain: Forgings for Blisks using fewer raw materials and providing better features. Thanks to the reduction of the necessary safety buffer, the advantages in weight can be exploited.
The project is divided into four different work packages. Each division is responsible for a certain aspect.
- WP1: Simulate the forge of a titanium raw material. Introduction of the new material DA718, which is resistant to high temperatures.
- WP2: Amongst other things, a protective layer against erosion in a high temperature environment is developed.
- WP3: An innovative ventilation system is introduced.
- WP4: Experiments and calculations towards flow phenomena
The work packages were divided again into sub-work packages.
Each work package achieved some positive results. In conclusion there are improvements in source materials, a higher resistance to high temperatures, a more precise forecast towards working temperature and an analysis in flow phenomena.
Findings of the study are published by a final report (German only), which is available online via the Technical Information Library (TIB) of the Hannover University: