University of Stuttgart. 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 are several research topic areas, including: (a) heat transfer and fluid flows within swirl chambers, (b) determination of entropy production from the flow field around a turbine guide vane, (c) flow structure and surface heat transfer from a turbine component endwall contoured using the ice-formation method, (d) investigations of rarefaction slip phenomena within a Viscous Disk Pump, (e) investigations of shock wave unsteadiness and interactions with nearby flow phenomena, and (f) particulate deposition effects within gas turbine hot-section components. For topic (b), considered 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). 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. 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. More recent efforts, using similar investigative approaches, consider the flow field around a turbine guide vane with film cooling produced by one or two rows of different shaped holes. Other recent investigations address flow structure and surface heat transfer from a turbine component endwall contoured using the ice-formation method, heat transfer and fluid flows within swirl chambers, rarefaction slip phenomena, shock wave unsteadiness and interactions with nearby flow phenomena, and particulate deposition effects within gas turbine hot-section components.

REFERENCES
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.

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.

Flow Structure and Surface Heat transfer From a Turbine Component Endwall Contoured Using the Ice-Formation Method (S. Winkler, B. Weigand, and P. M. Ligrani), International Journal of Heat and Mass Transfer, Vol. 120, pp. 895-908, May 2018.

Flow and Heat Transfer in Swirl Tubes – A Review (F. Seibold, P. M. Ligrani, and B. Weigand), Invited Journal Paper, International Journal of Heat and Mass Transfer, Vol. 187, Paper No. 122455, pp. 1- 26, May 2022.

Celebration of Professor Bernhard Weigand On His 60th Birthday (X. Chu, G. Yang, A. Terzis, V. Vaikuntanathan, W. Wang, Z. Li, G. Lamanna, S. Fest-Santini, M. Santini, G. E. Cossali, P. M. Ligrani, B. A. Younis, M. Crawford, P. Ott, J. Kohler, C. Rohde, C.-D. Munz, R. Helmig, and T. Zhao), International Journal of Heat and Mass Transfer, Vol. 188, Paper No. 122626, pp. 1-2, June 2022.

Particulate Deposition Effects on Internal Swirl Cooling of Turbine Blades (X. Yang, Z. Hao, F. Seibold, Z. Feng, P. M. Ligrani, and B. Weigand), ASME Transactions – Journal of Engineering for Gas Turbines and Power, Vol. 145, No. 5, Paper No. 051020, pp. 1-13, May 2023.

Heat Transfer in Convergent Swirl Chambers for Cyclone Cooling in Turbine Blades (F. Seibold, P. M. Ligrani, X. Yang, R. Poser, and B. Weigand), Applied Thermal Engineering, Volume 230, Part B, Paper No. 120744, pp. 1-18, July 2023.

Conjugate Heat Transfer Evaluation of Turbine Blade Leading-Edge Swirl and Jet Impingement Cooling with Particulate Deposition (X. Yang, Z. Hao, Z. Feng, P. M. Ligrani, and B. Weigand), ASME Transactions – Journal of Turbomachinery, Vol. 146, No. 1, Paper No. 011003, pp. 1-16, January 2024.

Experimental and Numerical Investigation of Jet Impingement Cooling onto a Rib Roughened Concave Internal Passage for Leading Edge Cooling of a Gas Turbine Blade (M. Forster, P. M. Ligrani, B. Weigand, and R. Poser), International Journal of Heat and Mass Transfer, Volume 227, Paper No. 125572, pp. 1-15, August 2024.

Normal Shock Wave Coherence Relative to Other Flow Events With High and Low Levels of Inlet Mach Wave Unsteadiness (W. Manneschmidt, P. M. Ligrani, M. Sorrell, A. M. Ciccarelli, and B. Weigand), Shock Waves, Vol. 34, pages 497–513, November 2024.

Heat Transfer and Aerodynamic Losses of Additively Manufactured Turbine Alloy Blades With Different Surface Enhancement Post-Processing (P. M. Ligrani, C. Bueschges, M. Tatge, B. Weigand, C. S. Subramanian, H. L. Collopy, Z. Taylor, J. Sheth, and P. Gradl), International Journal of Thermal Sciences, accepted for publication, to appear 2025.

Rarefaction Slip Phenomena Within a Viscous Disk Pump With Molecular Mean Free Path Sized Surface Roughness Elements (P. M. Ligrani, A. Pippert, and B. Weigand), Microfluidics and Nanofluidics, accepted for publication, to appear 2025.