0
Research Papers: Gas Turbines: Turbomachinery

Temperature Ratio Effects on Bluff-Body Wake Dynamics Using Large Eddy Simulation and Proper Orthogonal Decomposition

[+] Author and Article Information
Ryan Blanchard

Virginia Polytechnic Institute
and State University,
100S Randolph Hall,
Blacksburg, VA 24061
e-mail: rpberlin@vt.edu

Wing Ng

Virginia Polytechnic Institute
and State University,
100S Randolph Hall,
Blacksburg, VA 24061
e-mail: wng@vt.edu

Uri Vandsburger

Virginia Polytechnic Institute
and State University,
100S Randolph Hall,
Blacksburg, VA 24061
e-mail: uri@vt.edu

1Corresponding author.

Contributed by the Turbomachinery Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received October 11, 2014; final manuscript received November 23, 2014; published online June 2, 2015. Editor: David Wisler.

J. Eng. Gas Turbines Power 137(12), 122601 (Jun 02, 2015) (10 pages) Paper No: GTP-14-1576; doi: 10.1115/1.4030383 History: Received October 11, 2014

In this article, we describe the use of proper orthogonal decomposition (POD) to investigate how the dominant wake structures of a bluff-body-stabilized turbulent premixed flame are affected by the heat released by the flame itself. The investigation uses a validated large eddy simulation (LES) to simulate the dynamics of the bluff-body's wake (Blanchard et al., 2014, “Simulating Bluff-Body Flameholders: On the Use of Proper Orthogonal Decomposition for Wake Dynamics Validation,” ASME J. Eng. Gas Turbines Power, 136(12), p. 122603; Blanchard et al., 2014, “Simulating Bluff-Body Flameholders: On the Use of Proper Orthogonal Decomposition for Combustion Dynamics Validation,” ASME J. Eng. Gas Turbines Power, 136(12), p. 121504). The numerical simulations allow the effect of heat release, shown as the ratio of the burned to unburned temperatures, to be varied independently from the Damköhler number. Five simulations are reported with varying fractions of the heat release ranging from 0% to 100% of the value of the baseline experiment. The results indicate similar trends reported qualitatively by others, but by using POD to isolate the dominant heat release modes of each simulation, the decomposed data can clearly show how the previously reported flow structures transition from asymmetric shedding in the case of zero heat-release to a much weaker, but fully symmetric shedding mode in the case of full heat release with a much more elongated and stable wake.

Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Transparent view of CAD model of the test section showing the locations of the three windows relative to the vee-gutter flameholder. Flow direction is left to right.

Grahic Jump Location
Fig. 2

Transparent view of CAD model of the test section showing the locations of the three windows relative to the vee-gutter flameholder and the PIV laser sheet. Flow direction is left-to-right.

Grahic Jump Location
Fig. 3

Isometric view of dimensions of the domain used in the LES models based on the width of the flameholder w = 3.05 cm and an included angle of 70 deg

Grahic Jump Location
Fig. 4

Plan view dimensions of the domain used in LES models

Grahic Jump Location
Fig. 5

Illustration of flame's heat release imaged to simulate the line-of-sight integrated chemiluminescence imaged in the experiment

Grahic Jump Location
Fig. 6

X- and Y-locations of sampling points used for interrogating the velocity and heat release quantities in the flow. Also shown are the locations of the vee-gutter flameholder and the side window relative to the sampling grid and coordinate axes.

Grahic Jump Location
Fig. 7

Plot of time-averaged streamwise velocity profiles of the nonreacting condition at two locations downstream of the vee-gutter, x/w = 2.2 (left) and x/w = 3.8 (right)

Grahic Jump Location
Fig. 8

Time-averaged chemiluminescence contours of the measured (left) and simulated (right) flames. Contours have arbitrary units.

Grahic Jump Location
Fig. 9

RMS contours of chemiluminescence contours of the measured (left) and simulated (right) flames. Contours have arbitrary units.

Grahic Jump Location
Fig. 10

Time-averaged u-velocity contours for the five conditions studied showing a clear pattern of wake-elongation with increasing heat release

Grahic Jump Location
Fig. 11

Time-averaged line-of-sight reaction rate contours showing how the flame sheets' coalescence point moves farther downstream with increasing heat release until the two sheets finally remain separate permanently for the extreme case corresponding to the stoichiometric equivalence ratio

Grahic Jump Location
Fig. 12

Comparison of the first POD modes of u-velocity (left) and v-velocity (right) between the PIV measurements (top) and LES (bottom)

Grahic Jump Location
Fig. 13

Comparison between the first POD mode of line-of-sight chemiluminescence as measured in the experiment (top) and as simulated numerically (bottom)

Grahic Jump Location
Fig. 14

U-velocity contours of the first POD mode normalized by the bulk velocity

Grahic Jump Location
Fig. 15

V-velocity contours of the first POD mode normalized by the bulk velocity

Grahic Jump Location
Fig. 16

Line-of-sight reaction rate integral contours of the first POD mode

Grahic Jump Location
Fig. 17

Strouhal number of dominant shedding mode as a function of temperature ratio

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