NEW TEST FACILITY
Multistage Axial Compressor Test Facility
A Multistage Axial Compressor Test Facility has been installed at the Gas Turbine Research Establishment (GTRE), Bangalore. It consists of two power turbines driven by exhaust gas of an Avon engine. The two power turbine shafts are coupled through a high speed step-up gear box to obtain a single output shaft power of 80 kW (max) at the maximum speed of 15,000 rpm. To overcome the limitation on the available motive power, inlet throttling is resorted. Air from the atmosphere enters the test compressor through an inlet bellmouth and passes through a variable gate valve, throttling plates, flow straightner and settling chamber and exhausts through the collector box and exhaust ducting. Blockage at the outlet is varied through two butterfly valves and a surge relief valve.
Air mass flow is measured through an orifice plate located below the bellmouth. Total pressure and temperature recording at inlet and outlet of the compressor gives the overall pressure and temperature ratio. Rotor blade vibration is measured through a system which measures the instantaneous velocity of each rotor blade by employing casing transducer like capacitance or optical pickup. The modulation due to the rotor blade vibration is extracted from this signal through appropriate electronics. The capacitance transducer in turn measures the tip clearance between rotor blade and the casing. The pressure and the temperature are recorded with a scanni valve that is interfaced to data acquisition systems for processing the data into engineering units to generate performance plots and tables.