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

Nicole L Key

doi:10.1155/2014/392352

Abstract

Measurements acquired at the rotor exit plane illuminate the interaction of the rotor with the upstream vane row and the downstream vane row. The relative phase of the upstream and downstream vane rows is adjusted using vane clocking so that the effect of the upstream propagating potential field from the downstream stator can be distinguished from the effects associated with the wakes shed from the upstream stator. Unsteady absolute flow angle information shows that the downstream potential field causes the absolute flow angle to increase in the vicinity of the downstream stator leading edge. The presence of Stator 1 wake is also detected at this measurement plane using unsteady total pressure data. The rotor wakes are measured at different circumferential locations across the vane passage, and the influence of Stator 1 wake on the suction side of the rotor wake is evident. Also, the influence of the downstream stator is detected on the pressure side of the rotor wake for a particular clocking configuration. Understanding the role of the surrounding vane rows on rotor wake development will lead to improved comparison between experimental data and results from computational models.

Highlights

The inherently unsteady turbomachinery flow field resulting from the presence of stationary vane rows and rotating blade rows gives rise to blade row interactions that affect performance and unsteady forcing that can lead to high cycle fatigue
While vane clocking does not impact the time-averaged rotor performance, as documented in [17], the current paper presents rotor exit data acquired for these two clocking configurations to show how the surrounding stators impact the rotor flow field
Experiments were performed in a three-stage compressor to understand the effect of both the upstream vane and the downstream vane rows on the embedded rotor performance

Summary

Introduction

The inherently unsteady turbomachinery flow field resulting from the presence of stationary vane rows and rotating blade rows gives rise to blade row interactions that affect performance and unsteady forcing that can lead to high cycle fatigue. Researchers have shown that vane clocking can impact stage loss and efficiency by changing the amount of interaction the upstream vane wakes have with the downstream vane boundary layer [5,6,7,8]. In this research, clocking is used to isolate the flow field effects associated with the downstream vane potential field This change in phase of the potential fields between the upstream and the downstream vane rows can affect the unsteady forces acting on a rotor. The high resolution of data in the pitchwise direction is not commonly found in the literature, and this paper is one of the few that are able to look at how the vane potential field affects rotor wake shape, which has important implications as the forcing function to the downstream vane row. 0.26 0.46 0.35 0.45 0.33 0.44 0.31 number (abs) (rel) (abs) (rel) (abs) (rel) (abs) for developing and validating models utilized in multistage compressor calculations

Experimental Approach

Rotor Exit Flow Field

Rotor Wakes

Findings

Conclusions