Investigation of Flow Physics of Vane Clocking Effects on Rotor Resonant Response

Abstract

Vane clocking is the circumferential indexing of adjacent vane rows with identical vane counts. Vane clocking affects tone noise propagation, performance, and forced response characteristics in compressors. Recent vane clocking experiments performed in the embedded stage of the Purdue 3-Stage Research Compressor showed significant differences in the rotor 2 resonant response depending on the clocking configuration of stator 1 and stator 2, as measured by a nonintrusive stress measurement system. This research is focused on computing the fluidstructure interaction observed in this experiment to gain further insight into the flow physics associated with vane clocking. AU3D, an implicit, unsteady, unstructured, compressible flow solver is used to compute the vane clocking effects on rotor 2 resonant response, and the results are compared with experimental data. While many have investigated vane clocking effects on unsteady blade loading, this is one of the few investigations focused on rotor resonance. Nomenclature CL = clocking configuration P o = total pressure R = rotor R C = total pressure ratio S = stator W C = corrected mass flow rate

Influence of Upstream and Downstream Compressor Stators on Rotor Exit Flow Field

“…Researchers have shown that vane clocking can have a large impact on the unsteady aerodynamic forcing function, primarily the chordwise gust, in an axial compressor [9]. Vane clocking effects on the embedded rotor's resonant response for a Campbell diagram crossing at the first torsion mode were measured with a tip timing system [10], and CFD predictions matched the measured cyclic trend of rotor response with vane clocking configuration, where the rotor tip deflection decreased by as much as 33% with vane clocking [11]. A 60% reduction in the stator force amplitude was measured in a rotor-stator-rotor large-scale, low-speed axial compressor by clocking the downstream rotor.…”

Reconstructing Compressor Non-Uniform Circumferential Flow Field From Spatially Undersampled Data—Part 1: Methodology and Sensitivity Analysis

“…In the study conducted by Choi et al [3], results showed 80% differences in the mean blade response at design loading and 168% differences in the mean blade response at high loading by varying the clocking of the upstream stator rows. A follow-up computational study performed by Salontay et al [4] showed that the variations in the blade response are caused by the changes in the phase between the rotor upstream vortical and downstream potential forcing functions.…”

Reconstructing Compressor Non-Uniform Circumferential Flow Field From Spatially Undersampled Data: Part 1 — Methodology and Sensitivity Analysis

“…In the study conducted by Choi et al [3], results showed 80% differences in the mean blade response at design loading and 168% differences in the mean blade response at high loading by varying the clocking of the upstream stator rows. A follow-up computational study performed by Salontay et al [4] showed that the variations in the blade response are caused by the changes in the phase between the rotor upstream vortical and downstream potential forcing functions.…”