0
Research Papers: Fundamental Issues and Canonical Flows

Active Control of Flow Separation in a Radial Blower

[+] Author and Article Information
David Greenblatt, Guy Arzuan

Faculty of Mechanical Engineering, Technion–Israel Institute of Technology, Haifa 32000, Israel

J. Fluids Eng 132(5), 051202 (Apr 28, 2010) (6 pages) doi:10.1115/1.4001446 History: Received October 20, 2009; Revised March 04, 2010; Published April 28, 2010; Online April 28, 2010

An experimental investigation was undertaken as a proof-of-concept study for active separation control in a radial blower. Acoustic perturbations were introduced into the impeller housing of a small radial blower with fully stalled blades. Increases in the plenum pressure of 35% were achieved and, based on tuft-based flow visualization, it was concluded that the pressure increases were brought about due to excitation and deflection of the leading-edge separated shear layer. Within the parameter range considered here, the optimum dimensionless control frequencies were found to be O(0.5), irrespective of the blade orientation or number of blades. Moreover, the maximum pressure rise was achieved with an investment of only 2% of the fan input power. Backward bladed impeller blades exhibited slightly larger increases in pressure coefficients when compared with their forward bladed counterparts. The dependence of blower performance on reduced frequency was remarkably similar to that seen on flat plate airfoils at similar Reynolds numbers under periodic excitation.

FIGURES IN THIS ARTICLE
<>
Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 8

Flat plate airfoil flow visualization for the baseline case and two reduced excitation frequencies (flow from right to left). Perturbations are supplied by plasma-based actuators at the airfoil leading-edge (8). (a) Baseline, (b) F+=0.42, and (c) F+=2.1.

Grahic Jump Location
Figure 9

Individual frames of high speed photographs of the impeller leading-edge region. Tuft number 3, the furthest inboard, is highlighted. Phases 1 to 4 correspond to the four rows. Left hand column is the baseline (uncontrolled) case; right hand column is the controlled case.

Grahic Jump Location
Figure 10

Individual frames of high speed photographs of the impeller leading-edge region. Tuft number 3, the furthest inboard, is highlighted in on the right; opposite blade: tuft number 1, closest to the tip, highlighted in the left. Phases 5 to 8 correspond to the four rows. Left hand column is the baseline (uncontrolled) case; right hand column is the controlled case.

Grahic Jump Location
Figure 7

Flat plate airfoil lift data as a function of reduced excitation frequency. Perturbations are supplied by plasma-based actuators at the airfoil leading-edge (8). α represents the airfoil angle of attack.

Grahic Jump Location
Figure 6

Pressure coefficient rise as a function of reduced frequency for the backward-bladed and forward bladed impellers at 2760 rpm

Grahic Jump Location
Figure 5

Pressure coefficient rise as a function of reduced frequency for the backward-bladed impeller at two different fan speeds

Grahic Jump Location
Figure 4

Change in the plenum pressure coefficient as a function of the relative actuator excitation power input Ẇe/Ẇb for a forward bladed impeller; rotational speed=2760 rpm. Uncontrolled Cp=1.74.

Grahic Jump Location
Figure 3

Change in the plenum pressure coefficient as a function of the relative actuator excitation power input Ẇe/Ẇb for a backward-bladed impeller; rotational speed=2760 rpm. Uncontrolled Cp=2.1.

Grahic Jump Location
Figure 2

A schematic of the experimental setup, showing the blower, plenum, and speaker

Grahic Jump Location
Figure 1

The four-bladed impeller configuration shown installed in the blower housing

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In