Microwave Measurements from Benchtop Test Rig

Transcription

1 Microwave Measurements from Benchtop Test Rig Standards Michael Platt John Jagodnik Jeremy Weiss Certification Education & Training Publishing Conferences & Exhibits

2 Presenter Michael Platt Currently a Principal Engineer at Mechanical Solutions Managing several blade measurement projects for AFRL and NASA. Has been active in blade tip timing measurements since the late 80 s. Previously worked in dynamics analysis and test at Textron Lycoming (now Honeywell) and continued at Concepts ETI. 2

3 Outline Microwave Sensor Background Benchtop Rig Testing Flat plate blades Electric motor Air jet excitation Fan Rig Testing Swept blade shape Electric motor Magnetic excitation Sensor Development Form factor Temperature 3

4 Background Development and validation for microwave sensor Casing mounted sensor, with wide field of view Data stream is a continuous signal Use FFT to get blade mode identification Enables a hybrid tip timing system Enhance existing tip timing systems Use deflection data from time of arrival sensors Use frequency data from microwave sensors SBIR funding for sensor development and validation RF and shaker labs Spin pit and benchtop spin rigs Leading to hot section engine test in 1Q 2013

5 Hybrid Tip Timing System 5

6 Outline Microwave Sensor Background Benchtop Rig Testing Flat plate blades Electric motor Air jet excitation Fan Rig Testing Swept blade shape Electric motor Magnetic excitation Sensor Development Form factor Temperature 6

7 Rig Testing Setup Flat plate blades with zero blade angle Electric motor with open loop control 10,000 rpm top speed 7

8 Frequency & Order Domain Frequency Domain Data acquisition is done at constant number of points / second Spectra plotted versus time for speed excursions Spectra plotted versus speed for a single accel or decel Order Domain Data is re-sampled at constant number of points / revolution Y-axis of waterfall plot becomes order instead of frequency Spectra plotted versus time or speed, same as frequency domain 8

9 Order Spectrogram horizontal cursors define order tracking band, plotted at top order vs. time spectrogram vertical cursors define time tracking band, plotted at right 9

10 Sweep 6 Accel and decel Air jets on, max flow Radial probe orientation 10

11 Radar Order Response Sweep 6

12 Blade Deflection Response - Sweep 6

13 Blade Deflection Response - Sweep 6

14 Blade Deflection Response - Sweep 6

15 Deflection & Radar Response Sweep 6 Blade displacement from tip timing 3E amplitude from radar 15

16 Sweep 5 Accel to top speed, through 1 st bending peak Air jets on, max flow Decel to 1 st bending crossing with 3E Small speed excursions to max out the response 16

17 Radar Order Response Sweep 5

18 Blade Deflection Response Sweep 5 18

19 Blade Deflection Response Sweep 5 Blade displacement from tip timing 19

20 Deflection & Radar Response Sweep 5 Blade displacement from tip timing 3E amplitude from radar 20

21 Outline Microwave Sensor Background Benchtop Rig Testing Flat plate blades Electric motor Air jet excitation Fan Rig Testing Swept blade shape Electric motor Magnetic excitation Sensor Development Form factor Temperature 21

22 Fan Test Rig 5-blade fan stage Direct mount to electric motor DC electromagnets for excitation Portable design 22

23 Blade Deflection Response 23

24 Radar Spectrogram 24

25 Deflection and Radar Response 25

26 Outline Microwave Sensor Background Benchtop Rig Testing Flat plate blades Electric motor Air jet excitation Fan Rig Testing Swept blade shape Electric motor Magnetic excitation Sensor Development Form factor Temperature 26

27 Sensor Evolution 1. Prototype developed by BAE Systems Originally developed for FOD detection Showed some signal content from blade pass 10 GHz, 3 long, dia, 350º F 2. Gunn multiplexer and waveguide system Transmit and receive through the same antenna Better resolution from higher power (5 mw) and higher frequency (24 GHz) 25 GHz, 3 long, 1 dia, 250º F 27

28 Sensor Evolution 3. Material selection, packaging, and miniaturization Solid dielectric waveguide Separate sensor and electronics 25 GHz, 2 long, 0. 5 dia., threaded O.D. FCC conformity for intentional radiator 4. High temperature, specialized form factors SiO2 dielectric, high temperature steel Improved impedance matching High temperature cable, 1500 º F 25 GHz sensor, 8 mm dia, 2000º F 28

29 Conclusion Mode identification is at the core of tip timing systems Test planning, probe count and placement Tip timing data analysis Microwave sensor fills this technology gap well Validation a key part of the sensor development Extensive rig and spin pit testing Upcoming engine testing (compressor and turbine) Continuous sensor improvements Smaller, cheaper, better S/N ratio Custom form factors to adapt to specific geometry High temperature capability