Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Photographs of high temperature GFB rotordynamic test rig and bearings. T 1 ∼ T 10, T h, T out, T e, Tr DE and Tr FE represent locations of temperature measurement. Also shown a bearing sleeve with an axial slot to route a thermocouple installed at the bearing midspan (oblique view). Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Schematic view with dimensions (mm) of test rotor, cartridge heater, bearing support housing air feed enclosure. Noted locations of thermocouples for feed enclosure air temperature (T e ) and reference to control heater set temperature (T hs ). Flow paths of cooling air streams also shown. Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Photographs of test bump-type 1st generation gas foil bearing Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Test cases #1 and #2. T hs = 100 °C: free end bearing temperature rise (T 1 ∼ 4 − T amb ) versus air temperature rise in the enclosure (T e − T amb ). Arithmetic mean of (T 1 ∼ T 4 ) shown. Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Test cases #1 and #2. Heater set temperature 100 °C. No rotor spinning and rotor speed of 10, 20, and 30 krpm: recorded temperature difference of free end bearing sleeve OD above inlet cooling air temperature (T 1 ∼ 4 − T e ) versus cooling flow rate. Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Test Cases #1 and #2. Heater set temperature 100 °C. No rotor spinning and rotor speed of 10, 20, and 30 krpm: recorded temperature rise on (a) free end bearing sleeve OD (T 1 ∼ 4 − T amb ) and (b) free end rotor OD per unit cooling flow rate (L/min) versus cooling flow rate. Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Test case #3: FFTs of rotor responses at rotor drive end, vertical (DV) plane. Rotor speed = 10, 20 and 30 krpm. Cooling flow into bearings from ∼ 350 L/min to ∼ 50 L/min for each set rotor speed. Heater set temperature T hs = 65 °C. Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Test cases #4 (heater off) and #6 (T hs = 100 °C): waterfalls of rotor motion during decelerating from 30 krpm to rest. Heater off, cooling flow rate ∼ 350 L/min, deceleration = 16.7 Hz/s. Rotor drive end, vertical (DV) plane. Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Test cases #4 ∼ #6: rotor amplitudes of synchronous response. Slow roll compensation at 2 krpm. Cooling flow rate ∼ 350 L/min. Speed down ramp rate = 16.7 Hz/s. Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Prediction versus test data. Test case #2 (T hs = 100 °C): temperature of bearing sleeves (free and drive ends) versus cooling flow rate for operation at three shaft speeds. Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Prediction: Test case #2. Thin film temperature fields in free end bearing. T hs = 100 °C, rotor speed at 30 krpm. Cooling flow rate per each bearing 175 L/min. Cooling stream inlet temperature = 33 °C, rotor OD temperature = 80 °C uniform, T amb = 23 °C. Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Predicted free end FB direct and cross-coupled stiffnesses versus rotor speed. Whirl frequency equals rotor speed. Heater at T hs = 100 °C and increasing air cooling flow rates (per bearing). Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Predicted free end FB direct and cross-coupled damping coefficients versus rotor speed. Whirl frequency equals rotor speed. Heater at T hs = 100 °C and increasing air cooling flow rates (per bearing). Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Finite element model of test rotor supported on GFBs. Connecting rod and flexible coupling locate at drive end (left). Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Comparison of predicted and measured imbalance responses of test rotor supported on foil bearings. Test case #6. T hs = 100 °C. Cooling flow rate 350 L/min (into two bearings). Figure Legend:

Date of download: 6/2/2016 Copyright © ASME. All rights reserved. From: Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System J. Eng. Gas Turbines Power. 2012;134(10): doi: / Predicted heat convection coefficient of outer gap flow versus cooling flow rate (per each bearing). Test case #2 (T hs = 100 °C). Rotor speed of 10, 20, and 30 krpm. Free end bearing. Figure Legend: