Numerical Investigation of Active Flow Control of Low-Pressure Turbine Endwall Flows

In collaboration with C. Marks and R. Sondergaard, AFRL, Wright Patterson AFB

Funded by AFOSR

Highly loaded Low-Pressure Turbine (LPT) blades offer opportunities for lower costs and higher performance but suffer from unacceptable endwall losses. This has motivated research aimed at reducing the endwall losses by manipulating the passage vortex or the corner separation. Passive approaches such as profile and endwall contouring or active flow control did reduce endwall losses but require a more detailed understanding of the underlying flow physics to be better optimized.

General Electric F110-GE-100 low pressure turbine

General Electric F110-GE-100 low pressure turbine.

Sketch of endwall flow reproduced from Langston, L., “Secondary flows in axial turbines - A review,” Annals of the New York Academy of Sciences: Heat Transfer in Gas Turbine Systems, Vol. 934, 2001, pp. 11-26

Sketch of endwall flow reproduced from Langston, L., “Secondary flows in axial turbines – A review,” Annals of the New York Academy of Sciences: Heat Transfer in Gas Turbine Systems, Vol. 934, 2001, pp. 11-26.

Unsteady simulations of the AFRL L2F airfoil with and without fillet are being carried out. Both a laminar and a turbulent endwall boundary layer are considered. The results for the turbulent endwall boundary layer are in good agreement with PIV measurements. Without fillet a strong passage vortex is observed. The addition of the fillet reduces the strength of the passage vortex which decreases the total pressure loss. The present results provide motivation for future research aimed at an active or passive control of the flow with the objective to further reduce the endwall losses.

LPT blade at Re=100,000. Visualizations of Q=10 for instantaneous (left and center) and time-averaged data (right). The passage vortex coherence is reduced noticeably through the addition of the fillet.

LPT blade at Re=100,000. Visualizations of Q=10 for instantaneous (left and center) and time-averaged data (right). The passage vortex coherence is reduced noticeably through the addition of the fillet.

Oil flow visualizations by Marks et al. overlaid with skin friction vectors from simulation

Oil flow visualizations by Marks et al. overlaid with skin friction vectors from simulation.

  1. Gross, A., Marks, C., and Sondergaard, R., “Numerical Simulations of Active Flow Control for Highly Loaded Low-Pressure Turbine Cascade,” AIAA-2017-1460, 55th AIAA Aerospace Sciences Meeting, 9-13 January 2017, Grapevine, TX
  2. Romero Martinez, S.R., and Gross, A., “Numerical Investigation of Low Reynolds Number Flow in Turbine Passage,” AIAA 2017-1456, 55thAIAA Aerospace Sciences Meeting, 9-13 January 2017, Grapevine, TX
  3. Bear, P.S., Wolff, M., Gross, A., Marks, C., and Sondergaard, R., “Secondary Loss Production Mechanisms in a Low Pressure Turbine Cascade,” AIAA-2016-4554, 52nd Joint Propulsion Conference, 25–27 July 2016, Salt Lake City, UT
  4. Gross, A., Romero, S., Marks, C., and Sondergaard, R., “Numerical Investigation of Low-Pressure Turbine Endwall Flows,” AIAA-2016-0331, 54th Aerospace Sciences Meeting, 4 – 8 January 2016, San Diego, CA
  5. Gross, A., and Sondergaard, R., “Investigation of Low-Pressure Turbine Endwall Flows: Simulations and Experiments,” AIAA-2015-1290, 53rd Aerospace Sciences Meeting, 5 – 9 January 2015, Kissimmee, FL