Erweiterung der Steuerung eines Fan-Prüfstands um die Regelung aerodynamischer Betriebsgrößen zur Realisierung dynamischer Fuhrungsgrößenverläufe

Abstract

In order to carry out aeroacustical investigations on the noise generation of fans used in jet engines for the aviation industry, the German Aerospace Center (DLR) has developed a new test rig, named CRAFT (Counter Rotating Acousitc Fan Test Rig). In comparison to other test rigs, the CRAFT test rig has some special features, including two indenpendendly driven rotor-shafts and a high flexibility regarding configurations and instrumentation. Since its first commissioning, already several aeroacustical test series have been carried out. However, during these experiments the inputs of the test rig, such as rotor speed and the setting of a throttledevice for massflow control, have been operated manually in order to achieve or even hold an aerodynamic operating point of interest. According to this, only stationary operating points were possible and took a certain time to achieve. For future test series a control system is needed to compensate for disturabances at stationary operating points and dynamic changes in reduced rotor-speed and the massflow related flow coefficient have to be executed. In scope of this work a newly installed throttle device has been set up and integrated into the LabView operating software of the test rig. Furthermore a new part of the software has been devolped as a base for a control system and several modifications were made to the local control system of the electric drive, while only focoussing on the operation of one of the two shafts. In order to choose appropiate control loop structures and algorithms, a test series has been carried out, using a first stationary control, and providing data of the compressor-map of the stage, and the systems reactions to dynamic exitations with fast speed and throttle changes. The investigation of the obtained data showed a fast system reaction, with only a very small delay (around 100ms) between an input change and measuring of a stationary operarting point. Based on that information and the compressor map a simulink-model has been created and successfully validated. This model then has been used to simulate a control loop structure, showing its suitablilty in order to reach the set target of beeing able to follow dynamic reference trajectories in the form of reduced rotor speed and the flow coefficient.