In the present paper, direct numerical simulation (DNS) data of a low-pressure turbine (LPT) are investigated in light of turbulence modeling. Many compressible turbulence models use Favre-averaged transport equations of the conservative variables and turbulent kinetic energy (TKE) along with other modeling equations. First, a general discussion on the turbulence modeling error propagation prescribed by transport equations is presented, leading to the terms that are considered to be of interest for turbulence model improvement. In order to give turbulence modelers means of validating their models, the terms appearing in the Favre-averaged momentum equations are presented along pitchwise profiles at three axial positions. These three positions have been chosen such that they represent regions with different flow characteristics. General trends indicate that terms related with thermodynamic fluctuations and Favre fluctuations are small and can be neglected for most of the flow field. The largest errors arise close to the trailing edge (TE) region where vortex shedding occurs. Finally, linear models and the scope for their improvement are discussed in terms of a priori testing. Using locally optimized turbulence viscosities, the improvement potential of widely used models is shown. On the other hand, this study also highlights the danger of pure local optimization.
Investigation of the Accuracy of RANS Models to Predict the Flow Through a Low-Pressure Turbine
University of Melbourne,
Victoria 3010, Australia
Florence 50127, Italy
Niskayuna, NY 12309
Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received March 28, 2016; final manuscript received April 26, 2016; published online June 22, 2016. Editor: Kenneth C. Hall.
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Pichler, R., Sandberg, R. D., Michelassi, V., and Bhaskaran, R. (June 22, 2016). "Investigation of the Accuracy of RANS Models to Predict the Flow Through a Low-Pressure Turbine." ASME. J. Turbomach. December 2016; 138(12): 121009. https://doi.org/10.1115/1.4033507
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