Numerical and experimental research of stall inception on subsonic axial-flow compressor rotor

Abstract

Three-dimensional flow simulation and blade tip high-response static pressure measurements were performed on an isolated subsonic compressor rotor to gain more insight into the stall inception mechanism of the compressors. The Navier—Stokes solver, EURANUS, was used for computation. The steady-state flow solution was achieved at the convergence of a four-stage explicit Runge—Kutta integration scheme. The time-dependent calculation was implemented in the implicit dual time stepping scheme, which allowed for the solution of a steady-state problem at each physical time step. The high-response static pressure was measured using five Kulite sensors installed on the casing. The data acquisition frequency was 100 kHz. The recorded data were later analysed using wavelet analysis method. Correlating the simulation result and the measurement result, it was shown that as the compressor was approaching the near stall (NS) condition, the tip leakage vortex dissipation and shedding became violent. The shedding or dissipated flow structures would consequently scatter around the blade tip passage, which formed the initial onset of stall disturbances. These scattered vortexes would finally lead to compressor stall as they hit and merge with each other into low-frequency disturbance of significant size and energy. A stall pre-alarming method based on the monitoring of the low-frequency spectrum power at the NS condition was also suggested by this study.

Computer-Aided Solution to the Vibrational Effect of Instabilities in Gas Turbine Compressors

“…1) Lu, et al [3] and Okada et al [4] presented a draft on "Stall Inception in Axial Flow Compressor". A comprehensive measurement and theoretical analyses was used to determine which of the two types of instabilities (rotating stall or surge) would occur in a particular situation.…”

Study on Rotating Stall of Multistage Compressor Using Wavelets

“…3D unsteady Reynolds-averaged Navier-Stokes (URANS) methods have been successfully applied to simulation of rotating stall phenomenon in compressors [3]~ [12], and most of the studies concentrated on rotors or single-stage compressors. It is pointed by Wu [12] that, flow characteristics of rotating stall in single-row environment are different from that in multi-row environment.…”

Topological characterization of vortex structures on a transonic compressor stator during the stalling process

“…It had been found that if the rotor tip clearance is small stall inception occurs at the hub, but at clearances typical for a multistage compressor the inception is at the tip. 9 The tip leakage vortex breakdown and shedding became violent, 10 which was the major characteristic in the compressor flow-field, 11–13 and it was the principal factor of flow instability. 14,15 The main reasons for compressor stall are the flow separation and the large range of the low-energy flow that occur at the tip of the rotor blade near the stall point.…”