Experimental Stability Studies of the Herringbone-Grooved Gas-Lubricated Journal Bearing

Experimental studies were conducted on six rotors, 1 1/2 in. dia by 12 1/4 in. long operating in ambient air to high compressibility numbers. Herringbone-groove geometries and clearances were varied to determine their effect on half-frequency whirl (HFW). All rotors were operated vertically and without any applied radial load. Results show that half-frequency-whirl onset is very sensitive to radial clearance. Limited test results indicate that a fully grooved bearing is more stable than a partially grooved one, other parameters being equal. Generally fair agreement between theory and experiment was achieved for predicting HFW onset speeds.