UNIVERSITY OF STUTTGART
University of Stuttgart – Second Law Losses Around a Turbine Guide Vane
This research activity is a collaborative effort between Dr. Ligrani and Professor Bernhard Weigand, and associated graduate students, of the Institute of Aerospace Thermodynamics, of the University of Stuttgart in Germany. Of interest is the determination of entropy production from the flow field around a turbine guide vane, and the numerical simulation of this flow field by means of Computational Fluid Dynamics (CFD) 1. These CFD simulations are based upon RANS, the Reynolds Averaged Navier-Stokes equations, and are carried out using ANSYS CFX-14.0 and the Shear Stress Transport (SST) turbulence model. The flows around the vane from experimental investigation are simulated for three vane Mach number distributions, each of which is characterized by a different vane trailing edge Mach number. To obtain entropy production from the numerical flow field, two approaches based on second law analysis are utilized: a conventional and a differential one. The conventional approach describes global entropy production between two thermodynamic states by calculating it from the total pressure loss inherent to irreversible processes 2. The differential approach makes use of the entropy transport equation and yields local entropy production rates along pathlines directly from local flow field variables predicted by the CFD. Global entropy production is then determined by integrating local exergy destruction rates along pathlines, with respect to time 1.
1 Numerical Second Law Analysis Around a Turbine Guide Vane Using a Two-Equation Turbulence Model and Comparison With Experiments (S. Winkler, E. Kerber, T. Hitz, B. Weigand, and P. M. Ligrani), International Journal of Thermal Sciences, Vol. 116, pp. 91-102, June 2017.
2 Second Law Analysis of Aerodynamic Losses: Results for a Cambered Vane With and Without Film Cooling (P. M. Ligrani, and J. S. Jin), ASME Transactions-Journal of Turbomachinery, Vol. 135, No. 4, pp. 041013-1 to 041013-14, July 2013.