Akademik Veri Yönetim Sistemi
Proceedings of the 2nd Biennial European Joint Conference on Engineering Systems Design and Analysis. Part 1 (of 8), London, Kanada, 4 - 07 Temmuz 1994, cilt.64, ss.643-650
The linear superposition method (Powell, 1964) estimates the stability of externally pressurized (EP) air journal bearings with remarkable accuracy. In part-I (Uneeb et al., 1994), the steady state characteristics were presented using the superposition method. In this paper, the system response in the case of synchronous whirl is studied by using this approach and in addition, an estimate of the onset of self-excited whirl is made. The dynamic results are presented for translatory whirl of a rotor supported by two EP air journal bearings. For high clearances, the superposition theory makes use of a constant stiffness over the speed range of interest and predicts the dynamic response of the rotor. The results obtained by using an incompressible flow analysis on a finite bearing show good correspondence with the available experimental results of Tully (1966). The infinite width compressible flow solution gives a damped response which is 30% less near the resonant peak than the response predicted by incompressible finite width solution for similar conditions. Much of the discrepancy is attributed to the difference in lengths of the models.