A plain journal bearing is spontaneously unstable above a critical speed and loses much of its load carrying capacity when subjected to a load rotating at about half the speed of the shaft. The almost axially symmetric flow in a compressor can break down at low flow into a rotating pattern of stall cells but only the special case of a single propagating stall cell gives rise to a mechanical cou...

Based on the three-dimensional elliptic governing equations and the throttle model, an unsteady numerical simulation of rotating stall is undertaken in the case of G4-73 type centrifugal fan and the correctness of simulation results is verified by experiments. In this study a new rotating stall inception criterion is put forward, that the inlet flow or outlet back pressure fluctuations graduall...

April 10-15, 2016 Abstract A whole-annulus unsteady numerical simulation is carried out to investigate the mechanism of the rotating stall in a 1.5-stage low-speed axial-compressor. By comparing the experimental and numerical results, the numerical results are validated. The numerical simulation captures the most features of the rotating stall of the 1.5-stage compressor observed from the exper...

Ever increasing demand of higher pressure ratio of aero-engine compressors has always been hindered by two distinct aerodynamic instabilities. The first known as surge is; large one dimensional periodic mass flow fluctuation through the compressor, which involves the entire pumping system including compressor, ducting, plenum and throttle. The second is the rotating stall which can be character...

Results of a high-speed 10-stage axial-flow compressor test involving overall compressor and individual stage performance while stalling and operating in quasi-steady rotating stall are described. Test procedures and data acquisition methods used to obtain the dynamic stalling and quasi-steady in-stall data are explained. Unstalled and in-stall time-averaged data obtained from the compressor op...

A numerical technique capable of simulating blade-scale compression system ow instabilities over times scales spanning tens of rotor revolutions is presented. Simulations of stall inception, growth to fully-developed rotating stall, and evidence for hysteresis, secondary instabilities, and other nonlinear phenomena are presented. Signal processing techniques for ow asymmetry characterization ar...

The unstable flow with rotating-stall-like (RS) effects in a rotor-cascade of an axial compressor was numerically investigated. The RS was captured with the reduction in mass flow rate and increasing of exit static pressure with respect to design operating condition of the single rotor. The oscillatory velocity traces during the stall propagation showed that the RS vortices repeat periodically,...

The unstable flow with rotating-stall-like (RS) effects in a rotor-cascade of an axialcompressor was numerically investigated. The RS was captured with the reduction in mass flow rateand increasing of exit static pressure with respect to design operating condition of the single rotor.The oscillatory velocity traces during the stall propagation showed that the RS vortices repeatperiodically, and...