ABSTRACT
The ways in which rotor and stator interact is the subject of this chapter which begins with a discussion of bearings. The main focus is on oil journal bearings and rolling element bearings but other types are also discussed. Interaction through the working fluid is then discussed and the study is focused on a large centrifugal pump. This is appropriate as it conveys dense fluids with a relatively light rotor which is consequently influenced by the fluid. It is shown that the effects of the fluid can be very substantial. Attention is then focused on actual contact between rotor and stator. This can take two quite distinct forms: slow extended contact, often leading to heat generation, and rapid impact and rebound. The former leads to the Newkirk effect which is discussed in some detail, while the impact/rebound scenario is simulated giving some impression of the parameters involved. Whilst extensive studies have been made in this field, only rarely will adequate date be available to fully assess the situation. A related, yet distinct, phenomenon, the Morton effect, is outlined. The chapter ends with an estimation of the harmonics introduced into the vibration signal by rotor/stator contact under a range of conditions.
