Numerical and experimental investigation on dynamic performance of bump foil journal bearing based o

来源 :中国航空学报(英文版) | 被引量 : 0次 | 上传用户:zzm0901
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Widespread usage of bump-type foil journal bearing (BFJB) in oil-free micro-turbomachinery requires accurate predictions of dynamic performance characteristics, although it remains a challenging issue because BFJB reflects nonlinear both structurally and aerodynamically. This paper presented a simple experimental method to semi-directly obtain the minimum film thick-ness and dynamic stiffness of BFJB using the journal orbit. Numerical calculations and simulations are conducted to validate the experimental method. The micro-deformation and interaction of var-ious foils are taken into consideration to improve the model precision. The results from the numer-ical model regarding the BFJB dynamic characteristics are compared with the experimental results coming from a dedicated test rig, which shows that the experimental results fluctuate obviously and agree not well with the numerical results at the start stage due to the presence of dry friction at that time, nevertheless, they show fantastic agreement as soon as a gas film is gradually generated to sep-arate the shaft from the top foil. Therefore, the proposed experimental method is effective to predict film thickness and dynamic characteristics during the period from the lift-off time to the land-off time. The dynamic characteristics, along with the journal orbits also can be used to rapidly predict the dynamics behavior of rotor-bearing systems.
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