GB991000A - High speed rotor systems - Google Patents

Abstract

991,000. Balancing shafts; vibration dampers. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Nov. 23, 1961 [Aug. 29, 1960], No. 29783/60. Headings F2S and F2U. An elongate high-speed rotor system comprises two concentric tubular rotors of differing whirl critcal speeds which are connected for rotation at the same speed and the annular clearance between which is such that at their critical speeds the rotors engage. The engagement between the rotors causes the whirl set up in the rotor which is at critical speed to collapse before the amplitude of its deflection exceeds an acceptable value. The whirl critical speed is proportional to where R is radius of rotor, 1 is length of rotor between supports, E is Youngs modulus for the rotor material and P is the density of the material. In Fig. 1 the two tubular rotors 11, 12 are of substantially different radii, the rotors being connected at their ends by rings 13 and supported by resiliently mounted gas bearings 15. Rings 14 arranged on the rotor 11 at antinodal positions engage the rotor 12 under whirl conditions. In another construction, Fig. 2, the two rotors 21, 22 are not of significantly different radii and are connected at their ends by thin rings 23. The two rotors are given different values of E by forming circumferential grooves 26 on the rotor 21, the rotors engaging one another at antinodal positions under whirl conditions. In a further construction, Fig. 3, the rotors 31, 32 are made of different length by making the inner rotor 31 in two sections 31a, 31b connected at their ends to the rotor 32 by thin rings 33, 38. The sections 31a, 31b are connected by a resilient coupling 37. In a fourth embodiment (not shown) the two rotors are made of materials having different densities.