0
TECHNICAL PAPERS

Active Flow Control in Circular and Transitioning S-duct Diffusers

[+] Author and Article Information
A. M. Pradeep

Department of Aerospace Engineering, Indian Institute of Technology, Bombay, 400 076, Indiaampradeep@aero.iitb.ac.in

R. K. Sullerey

Department of Aerospace Engineering, Indian Institute of Technology, Kanpur, 208 016, Indiasuller@iitk.ac.in

J. Fluids Eng 128(6), 1192-1203 (May 05, 2006) (12 pages) doi:10.1115/1.2353263 History: Received February 24, 2006; Revised May 05, 2006

Performance enhancement of three-dimensional S-duct diffusers by secondary flow and separation control using vortex generator jets is the objective of the current experimental investigation. Two different diffuser geometries namely, a circular diffuser and a rectangular—to—circular transitioning diffuser were studied. The experiments were performed in uniform inflow conditions at a Reynolds number of 7.8×105 and the performance evaluation of the diffusers was carried out in terms of static pressure recovery and quality (flow uniformity) of the exit flow. Detailed measurements that included total pressure, velocity distribution, surface static pressure, skin friction, and boundary layer measurements were taken and these results are presented here in terms of static pressure rise, distortion coefficient, total pressure loss coefficient, and the transverse velocity vectors at the duct exit. The use of vortex generator jets resulted in around 26% in total pressure loss and about 22% decrease in flow distortion coefficients in the circular and transitioning diffusers. The mass flow rate of the air injected through the VGJ was about 0.1% of the mass flow rate of the main flow for secondary flow control and about 0.06% of the main flow for separation control. The physical mechanism of the flow control devices used has been explored. The structure of the vortices generated by the control methods are presented in the form of smoke visualization images. The method of flow control used here is perceived to have applications in turbomachinery like turbines and compressors.

Copyright © 2006 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

(a) Circular diffuser geometry. (b) Rectangular-to-circular transitioning diffuser geometry.

Grahic Jump Location
Figure 2

(a) Vortex generator jet geometry and flow arrangement. (b) Definition of coordinate system and vortex generator jet angles.

Grahic Jump Location
Figure 3

Active control circuit

Grahic Jump Location
Figure 4

(a) Wall static distribution along the inner and outer walls of the circular diffuser. (b) Wall static distribution along the inner and outer walls of the transitioning diffuser.

Grahic Jump Location
Figure 5

Total pressure loss coefficient contours at the exit of (a) bare circular diffuser (b) diffuser with VGJ

Grahic Jump Location
Figure 6

Total pressure loss coefficient contours at the exit of (a) bare transitioning diffuser (b) diffuser with VGJ

Grahic Jump Location
Figure 7

Transverse velocity vectors at the exit of (a) bare circular diffuser (b) diffuser with VGJ

Grahic Jump Location
Figure 8

Transverse velocity vectors at the exit of (a) bare transitioning diffuser (b) diffuser with VGJ

Grahic Jump Location
Figure 9

(a) Wall static pressure distribution along the inner and outer walls of the circular diffuser. (b) Wall static pressure distribution along the inner and outer walls of the transitioning diffuser.

Grahic Jump Location
Figure 10

(a) Skin friction distribution along the inner and outer walls of the circular diffuser. (b) Skin friction distribution along the inner and outer walls of the transitioning diffuser.

Grahic Jump Location
Figure 11

Total pressure loss coefficient contours at circular diffuser exit (a) bare diffuser (b) with continuous jets (c) with active feedback control

Grahic Jump Location
Figure 12

Total pressure loss coefficient contours at transitioning diffuser exit (a) bare diffuser (b) with continuous jets (c) with active feedback control

Grahic Jump Location
Figure 13

Structure of vortices at downstream locations (a) 10 jet diameters (b) 20 jet diameters, and (c) 30 jet diameters

Grahic Jump Location
Figure 14

Schematic of the structure of the vortices generated by a VGJ

Grahic Jump Location
Figure 15

Structure of vortices at downstream locations (a) 30 jet diameters (b) 90 jet diameters, and (c) 120 jet diameters from the VGJ

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