MINIATURE ENGINEERING SYSTEMS GROUP DEVELOPMENT OF GAS FOIL BEARINGS FOR MINIATURIZED RTB CRYOCOOLER – PHASE III MATHEMATICAL MODELING AND ANALYSIS - II Presented by  K.V.Krishna Murty MMAE

Animated Journal Gas Foil Bearings

DIMENSIONS OF THE GAS FOIL BEARING Journal Bearing  Outer diameter = 43 mm Journal inner diameter = 33 mm Inner hollow cylinder thickness = 1 mm Inner hollow cylinder axial length = 7 mm Foil axial length = 5 mm Gap between inner hollow cylinder and shaft = 5 mm

DIMENSIONS OF THE GAS FOIL BEARING Thrust Bearing  Dimensioning is still in progress.

MISCELLANEOUS Both the bearings would be of ‘Split type’ so as to facilitate for easy mounting.  Both the bearings would be of ‘Split type’ so as to facilitate for easy mounting.  Two ‘Split-Type Journal Gas Foil Bearings’ would be mounted on the larger diameter portion of the shaft on either side of the motor and would be bearing the radial load.  Two ‘Split-Type Thrust Gas Foil Bearings’ would be mounted on the smaller diameter portion of the shaft on either side of the motor and would be bearing the axial load.

Split Gas Foil Bearings – courtesy MiTi.

Current work  The Mechanical and Thermal analyses Stiffness and Damping Heat Transfer Stiffness and Damping Heat Transfer are being continued using software. are being continued using software.  An efficient solver is currently being coded in MATLAB for solving for the displacements in a matrix in the analysis of ‘Critical Speed’.

Future work To start the fluid flow analysis.To start the fluid flow analysis. To work in close association with the ‘Tribological Group’ regarding coatings once the foil structure is finalized.To work in close association with the ‘Tribological Group’ regarding coatings once the foil structure is finalized. To move into the final phase of development i.e., to arrive at a detailed design for fabrication and testing.To move into the final phase of development i.e., to arrive at a detailed design for fabrication and testing.