Long-term use for DLR
This research group helps to secure and augment the traditionally good position of DLR in the field of diagnostic techniques. Since DLR strives to organise its activities in the framework of large projects and with the help of third party funding, the possibilities to test and develop new measurement techniques for fluid flows are diminishing. Being able to provide and handle unique diagnostic tools is often the decisive factor to successfully acquire contract work and to perform new kinds of experiments. Thus, the Helmholtz-University Young Investigators Group offers an ideal opportunity to test several promising, innovative ideas of great interest to the DLR, which could not be pursued otherwise. If the development is successful, it will enrich the measurement portfolio of DLR, since the technological know-how will be transferred in the course of the project.
Short- and mid-term use for DLR
The group is located in close vicinity to the DLR-Division for Engine Acoustics (Former Division for Turbulence Research), which specialises in different kinds of acoustic research. Therefore, the section will have considerable interest in the development of a new type of microphone, especially since the section does not cover the field of microphone development yet, but has to rely on commercially available products. The microphones will be tested in a model combustor of DLR in Berlin and will subsequently be applied to combustion test rigs of DLR-Cologne, to provide new insights into the generation mechanisms of combustion oscillations.
The FRS-project will be an important support to a current DFG-project on combustion noise: The DLR Section of Turbulence Research plans to experimentally verify and quantify entropy noise. Because of the difficulties in detecting entropy waves this task proved to be more complex than expected. The FSR technique will hopefully help to overcome these difficulties and to deliver the promised results.
The first practical task of the TGS-technique will be to measure temperature distributions in the DLR cascade and compressor test rigs in Cologne. The ability to non-intrusively measure the temperature in compressors or turbines will be unique; and will strengthen the position of DLR in acquiring third-party funding.
In return, the Institute of Propulsion Technology will support the Helmholtz-University Young Investigators Group with expensive optical equipment and with its know-how in laser measurement techniques as well as with its experience in acoustics and combustion research. The institute will supply special lasers for TGS and FSR, iodine cells and all electronic devices necessary for laser frequency control, and will furthermore help to construct and build the optical fibres for the microphones.