Near-wake measurement in a rotor/stator axial compressor using slanted hot-wire technique

Abstract

Three-dimensional near-wake structure behind a rotor was measured using slanted hot-wire technique in a large-scale, low-speed, rotor/stator axial compressor. Unsteady flow interaction between blade rows was varied by setting the axial gap between rows at 10% and 30% of rotor chord. Results show that stronger flow interactions between blade rows, or closer axial gap, produce more pronounced time variation within the rotor wake. All parameters measured three component velocities, yaw and pitch anglesvaried strongly within the wake, and are quantified. List of symbolsC airfoil chord (same for all blades) u a , u F , u r axial, tangential and radius components of velocity in compressor Coordinates V b blade velocity at mid-span W rotor relative velocity

Wake Vorticity Decay and Blade Response in an Axial Compressor With Varying Axial Gap

“…Comparison of wake %tonicity between analytical solution and that discretized using central difference with dix=diy=2.9% wake width. Hsu and Wo (1997) provides details on velocity measurement using the slanted hot-wire technique, with an overall accuracy of +1-3% in magnitude and +/-2 degree in flow angles. The hot-wire was located at the stator mid-pitch circumferential direction and was traversed axially, as will be discussed below.…”

Investigation of Stator Wake Variability in Single Stage Axial-Compressor

“…Nicole L. Key [10] etc have brought out some experimental studies of the variation orderliness of the rotor wake in a three stages axial-compressor, especially analyzed the influence of the rows interaction on the rotor wake flow under the designed and high-load operation conditions. S. T. Hsu [11] etc have measured the rotor wake flow of a single stage axial-compressor including inlet guide vane, and studied the variation of the wake configuration along with the adjustment of the axial gap between the rotor and stator rows, under the designed and high-load operation conditions respectively. The above two research works all indicate that the variation of the operation conditions and rows interaction play a very important role of the wake configuration transformation.…”