G AS F OIL B EARINGS FOR T URBO AND S UPER C HARGERS Luis San Andrs - PowerPoint PPT Presentation

New Proposal May 2016 Year I G AS F OIL B EARINGS FOR T URBO AND S UPER C HARGERS Luis San Andrés Wonbae Jung M.S. student Mast-Childs Chair Professor

Justification Gas Foil Bearings (GFBs) • A bump type foil bearing(BFB) comprises of one or more bump foil strip layers (under-spring) and a top foil, both elements secured into a bearing cartridge. • BFBs are prone to show low frequency whirl motions due mainly to the hardening characteristic of the under-spring structure. Figure 1. The first generation bump-type gas foil bearing [1] Turbochargers for passenger vehicles operate under stringent conditions. Measurements of BFB performance at a high speed and under a high temperature will provide a road to design BFBs applicable to automotive turbochargers and electrical superchargers. 2

Background Figure 2. Measurements of temperatures on the rotor surface and bearing cartridges. Rotor amplitudes of synchronous response [2] • The rotor and bearings survived numerous start up-shutdown events, and steady speed operation for several hours, with added imbalance masses as large as 360 mg (u=22.6 µm) at 50 krpm speed and 200 ºC heater temperature (~ max. 100 ºC at the rotor OD). • With an abundant cooling flow rate (160 LPM), the performance of the test bearings is not significantly affected by increasing rotor temperatures. 3

2016 proposal to TRC 1. Modify test rig for operation at a high temperature (~250ºC) by inserting an electric cartridge heater into the hollow shaft. 2. Conduct static load tests to ~70 krpm to evaluate the drag friction of various material coatings deposited on the top foil of a first generation BFB. 3. Deliver dynamic loads (max. 100N) by using the e-shakers system to identify BFB rotordynamic force coefficients while operating at a constant speed (60 krpm) and with shaft temperature increasing to 250ºC at intervals of 50ºC . 4

Objective of research The results of the research will characterize quantitatively the life and endurance of various coatings applicable to high temperature gas bearings. In subsequent years, the research will continue to develop inexpensive foil bearings, radial and thrust, ready for deployment into oil-free turbocharges and electric super-chargers, for example. Benefits : increased reliability and alleviate NVH issues. 5

TRC Budget 2016-2017 Year I Year I Support for graduate student (20 h/week) x $ 2,300 x 12 $ 27,600 months Fringe benefits (2.7%) and medical insurance ($360 /month) $ 5,065 Tuition three semesters ($ 400 credit hour x 24 h/year) $ 9,600 Supplies and instrumentation (insulating cover) $ 2,700 $ 44,965 The TAMU foil bearing program is well known for its innovative models and procedures. BFBs offer commercial potential. 6

Questions (?) Learn more at http://rotorlab.tamu.edu 7

Reference [1] Ryu, K., 2011, “Effect of Cooling Flow on the Operation of a Hot Rotor- Gas Foil Bearing System,” Ph.D Thesis, Texas A&M University, College Station, TX. [2] Chirathadam, T.A., 2012, “Metal Mesh Foil Bearings: Prediction and Measurement of Static and Dynamic Performance Characteristics,” Ph.D Dissertation, Texas A&M University, College Station, TX. [3] Sim, K., Lee, Y.B., 2014, “Identification of the dynamic performance of a gas foil journal bearing operating at high temperatures,” Journal of Mechanical Science and Technology, Vol 28, Issue 1, pp43-51 8