Session: 40-03 Compressor Flow and Interaction Effects

Submission Number: 179361

The Effect of Wake Reduced Frequency on Separated Flow Transition Over a Simulated Axial Compressor Blade Under Low Reynolds Number Flow 

The effect of unsteady wake interactions with flow in downstream blade passages has been studied widely in axial turbines but has received less attention in axial compressors, perhaps due to the reduced loading conditions within compressor stages. The interaction between upstream generated wakes and the blade boundary layer under adverse pressure gradient conditions is the subject of this paper. The flow over the suction surface of axial compressor blades is typically subject to adverse pressure gradients and undergo separated flow transition when operating at low Reynolds number conditions. The separation region causes larger losses through momentum deficit and therefore a reduction in overall efficiency. The upstream wakes influence the transition process of the temporarily supressed separation region. The specific effect of Reduced frequency is studied here by performing a parametric analysis at a Reynolds number of 210,000. Three reduced frequencies, 0.64,1.28 and 2.56, are explored in this study. The spatial and temporal development of the flow field is described via data obtained using Particle Image Velocimetry. For each case, six equally spaced time-snapshots within the wake-cycle are used to illustrate the influence of the wake-boundary layer interaction and convection speeds. The paper goes on to describe the interaction of the convective features with the separation region and the ability of the latter to re-establish following the wake induced suppression under the different reduced frequency conditions.

Presenting Author: Thomas Irps University of Sussex

Presenting Author Biography: Thomas Irps is a final year postgraduate research student at the Thermo-Fluid Mechanics Research Centre at the University of Sussex.

Authors:

Thomas Irps University of Sussex
Vasudevan Kanjirakkad University of Sussex