NEW TEST FACILITY
Fan Test Facility
The Gas Turbine Research Establishment (GTRE), Bangalore, installed a fan test facility for evaluating the performance of fans in axial compressors of aeroengines. The test section in this facility is supplied with air, drawn through bell mouth and orifice plate via an in-let throttle valve which controls the air flow. The throttle valve is followed by Plenum chamber where the air flow gets streamlined before entering into test section. The distortion of flow pattern at the inlet of fan is simulated in this facility using screens. The only distortion is the disturbances created in the fan-inlet during flight. When there is no distortion, the fan characteristics are called clean. The air is collected by collector-box and exhaust to atmosphere through exhaust ducts and valves. Downstream valves are used for flow control/back pressure variation and surge relief. All valves are low pressure loss and quick response time type. The rig is driven by 1-2 kw thyristor-controlled electric motors. Rig instrumentation consists of equipment for the measurement of vibration, lubrication oil pressure and temperature, blade vibration sensors, and clearance and pressure fluctuations by case-mounted pick ups. Total pressure, temperature, wall static pressure and temperatures, fast response pressure sensors, wedge static probes, and non-nulling 3-5 hole flow angle sensors have also been used in this rig. Air flow rate is measured by calibrated plate or venturi. Rotating speed is measured by magnetic pick-ups. Flow pattern fine details are captured by laser velocimetry or holographic techniques. The high speed data acquisition system in the rig is backed up by a multichannel tape recorder. Stall and vibration warning is done with the help of PC monitors.