TURMA - Turbine test bench
A new test bench dedicated to turbine development and understanding. Test rig for two stage turbine, co or contrarotative turbines.
This new test bench (working since 2008) is dedicated to turbine development and understanding.
An understanding of the HP-LP turbine interaction is a major goal in the future years. The development of unsteady viscous codes involves experimentally identifying as completely as possible the different features of the flow. In order to validate these codes it is necessary to build accurate and comprehensive data bases.
New technologies and new concept need also to be assessed: reduction of the number of blades and wheels as well as counter-rotating stages. In the 1990's, no test benches existed for two-stages turbines where the high pressure stage is followed by a low pressure stage.
CHARACTERISTICS OF THE BENCH
|HP turbine||BP turbine|
|Maximal power||0.75 MW||2 MW|
|Maximal torque||3130 Nm||2730 Nm|
|Maximal speed||12,500 rpm||9,000 rpm|
Without assembling the major engine components (compressor, combustion chamber and turbine), it is extremely difficult to reproduce experimentally in a test bench the real operating conditions of a high pressure turbine. However for aerodynamic studies less severe conditions are sufficient. The pressure of inlet air is limited to 4 bar. The temperature of reserved air is 450 K, which requires the use of a heater of 2.2 MW.
The maximum mass flow is 11 kg/s, supplied by two of three 9 bar air compressors of the CMA. The pressure ratio of the two stages is such that the discharge is at a pressure lower than the atmospheric pressure, which requires the extraction of the air by means of a compressor of 2.5 MW. The bench can accommodate a range of models corresponding to present or future designs having actual size or slightly sub-scale. The energy supplied by the turbines is absorbed by hydraulic brakes, with the following characteristics:
- Steady measurements = 64 analog channels, 15 bits A/D converter, analog lowpass filtering with a bandwidth from 10hz to 2500 Hz. Digital lowpass filtering with a bandwidth from .5hz to 10 Hz. Steady accuracy ±1 mV, resolution 0.6mV.
- On request, unsteady measurements = 64 analog channels at 100 kHz per channel. 12 bits A/D converter, digital lowpass filtering with a bandwidth from 0 to 20 kHz (if necessary the number of channels can be increased).
- Steady pressures = 416 channels (by 98Rk PSI®, system 9816)range +/-5psi and +/-15psi).