Within the research programs at the Institute for Thermal Turbomachinery and Machine Dynamics in 1995 work started at Graz University of Technology to design and build a transonic test turbine facility.In November 1999 the turbine test facility was run for the first time. This facility is driven by the existing compressor station of 3 MW power and allows testing of transonic gas turbine stages in full flow similarity. The test stand gives access of conventional pressure and temperature probes as well as of optical measurement devices such as Laser-Doppler-Velocimetry (LDV) and Particle-Image-Velocimetry (PIV) systems. Changing demands from research projects forced to several modifications. Since the commissioning more than 100 test runs with three different transonic turbine stages were performed. Measurement data were collected during an overall testing time of about 160 hours.

Pressurized air delivered by a separate electrically driven compressor station of 3 MW power is fed to the turbine stage to be tested. The test turbine drives the brake compressor shown at right. The pressurized air from the brake compressor can be added to the air from the compressor station in a mixing chamber. The air from the compressor station may be cooled to about 50 °C, whereas the temperature of the brake compressor air depends on the pressure ratio.  The exhaust air from the turbine normally flows through an exhaust line directly to the silencers in the exhaust tower. Optionally a suction blower driven by a 750 kW helicopter engine may be inserted into the exhaust line to reduce the turbine back pressure and thus increase the turbine overall pressure ratio.

View of the brake compressor and the turbine mixing chamber ( Full size, 78 kB)	Flow scheme of the facility (Full size, 42 kB)	Flow inside the turbine (Full size, 53 kB)	View of turbine rotor  (Full size, 35 kB)
View of turbine stage  (Full size, 36 kB)	Instrumentation for PIV measurement  (Full size, 48 kB)	Control and monitoring station of the test facility  (Full size, 85 kB)

• Continuously operating cold flow test facility in open cycle
• Use of a compressor as brake for enhancing mass flow
• Wide adjustable speed range of the test rig with the first bending mode of the two shafts below 7000 rpm and the second bending mode sufficiently higher than the maximum speed of 11550 rpm
• Stable tilting pad bearings also at the turbine shaft
• Overhung-type turbine shaft for easy disk assembly
• All casing parts horizontally split for easy maintenance (except diffuser inserts)
• Modular design for quick modification of test setup
• Possible cooling air flow supply of blades and cavity
• Test section with high flexibility of meridional path [mm]:
• Stage inlet adapters starting at inner diameter D_i = 360 and outer diameter D_out = 620
• Test section inserts maximum diameter D = 800
• Diffuser insert flanges D_i  = 720
• Test section length L = 406
• Diffuser length L_Diff = 620
• Test turbine stage operational limits:
• Inlet pressure max. 4.6 bar (5 bar)
• Inlet temperature max. 185°C
• Outlet pressure 0.97 without or 0.80 bar with suction blower operation
• Maximum mass flow: 9.5 kg/s without and about 20 kg/s with air of brake  compressor
• Maximum speed 11550 rpm
• GHH brake compressor:
• Nominal speed 11175 rpm
• Nominal outlet temperature 229°C
• Maximum coupling power 2.5 MW at -15° IGV position

If you are interested in more details of our transonic test turbine, please download description_turbine.pdf (631 kB)

Publications to our transonic test turbine for download

• Erhard, J., 2000, "Design, Construction and Commissioning of a Transonic Test-Turbine Facility", PhD thesis at Graz University of Technology, Austria ( pdf, 13 MB)
• Erhard, J., Gehrer, A., 2000, "Design and Construction of a Transonic Test-Turbine Facility", Proc. ASME International Gas Turbine and Aeroengine Congress, Munich, Germany, paper 2000-GT-0480 (pdf, 2075 kB)
• Neumayer, F., 2001, "Time-Resolved Simulation of the Operational Behaviour of a Test Turbine Facility", Proc. of the 4th European Conference on Turbomachinery, Firenze, Italy, Paper-No. ATI-CST-044/01 (pdf, 690 kB)
• Neumayer, F., Kulhanek, G., Pirker, H.-P., Jericha, H., Seyr, A., Sanz, W., 2001, "Operational Behavior of a Complex Transonic Test Turbine Facility", to be presented at ASME International Gas Turbine and Aeroengine Congress, New Orleans, USA (pdf, 367 kB)
• Seyr, A., Kulhanek, G., Neumayer, F., Rossi, E., Sanz, W., 2001, "Performance Measurement of the Second Stage of a Transonic Turbine", to be presented at ASME International Gas Turbine and Aeroengine Congress, New Orleans, USA (pdf, 3207 kB)