Persönlicher Status und Werkzeuge

Gasdynamik


Forschungsschwerpunkte:

1. Kavitierende Strömungen und Vorhersage kavitationsinduzierter Erosion

  • Untersuchung von Kavitationsphänomenen in Diesel-Injektoren, auf Schiffschrauben sowie in Kanalströmungen
  • Entwicklung von Modellen zur quantitativen Vorhersage von Erosionsrisiken durch Kavitation (räumliche und zeitliche Entwicklung der Schädigung)
  • Untersuchung des Einflusses von gelöstem Gas auf Kavitation
  • Analyse der Interaktion kavitierender Strömungen mit turbulenten Fluktuationen und beweglichen Geometrien (Öffnen und Schließen von Injektoren und Ventilen)
  • Abschätzung des Einflusses von Kavitation auf aufbrechende Freistrahlen

1.1 Ansatz 

  • Kompressible Strömungssimulationen
    • Auflösung kollapsinduzierter Stoßwellen (>10000 bar)
    • Zeitgenaue Wellendynamik (Zeitschritt < 10-9 s)
  • Integrierte thermodynamische Modelle für Phasenübergänge durch Kavitation:
    • Lokales Gleichgewicht (mechanisch und thermisch)
    • Keine metastabilen Zustände
    • Gleichgewichtsphasenübergang
  • Neuartiger Kollapsdetektor zur Erosionsvorhersage
  • Untersuchung kanonischer Strömungen mittels
    • reibungsfreier Euler-Strömungslöser
    • Large-Eddy-Simulation (LES)
  • Entwicklung von Immersed Boundary Methoden für bewegliche Geometrien in schwach kompressiblen Flüssigkeiten

1.2 Kavitation in Diesel Injektorsystemen

Im Rahmen verschiedener Forschungsvorhaben werden einzelne Baugruppen in Diesel-Injektorsystemen untersucht. Dies umfasst sowohl den Steuerbereich, wie auch den vorderen Injektorbereich.

 

Kavitation in Steuerräumen

Identifikation und Vorhersage erosionsgefährdeter Bereiche in komplexen Innenströmungen.

Kavitation in Steuerdrosseln

Untersuchung der Interaktion von Turbulenz mit Kavitation in Steuerdrosseln mittels wandaufgelöster LES unter verschiedenen Austrittsdrücken.

 

Modellierung Gesamtsystem (inkl. beweglicher Geometrien)

Simulation von Strömungen in schliessenden Ventilen und Injektoren mit dynamischem Nadelhub mittels Immersed Boundary Methoden für schwach kompressible Strömungen.

 

Gasmodellierung

 

1.3 Kavitation auf Schiffschrauben und in komplexen Strömungsgeometrien

Kavitationskanal

Untersuchung der Kavitationsgebiete hinter einer scharfen Strömungsumlenkung mittels reibungsfreier Analyse.

Betriebungspunkt 66kPa
Betriebungspunkt 62kPa


Kavitation auf Schiffschrauben

 

2. Nanopartikel

 

3. Shock-Trains



Lehre:

Die Vorlesung Gasdynamik wird wieder im Sommersemester 2015 angeboten!


Publikationen:

Journals

  • Mihatsch, M. S., Schmidt, S. J., and Adams, N. A.:
    Quantitative Prediction of Erosion Aggressiveness through Numerical Simulation of 3-D Unsteady Cavitating Flows.
    To be submitted in 2014
  • Egerer, C., Hickel, S., Schmidt, S., Adams, N.:
    LES of Turbulent Cavitating Shear Layers
    Nagel WE, Kröner DH, Resch MM, editors. High Performance Computing in Science and Engineering ‘13: Springer International Publishing; 2013. p. 349-59.
  • Sezal, I.H., Schmidt, S.J., Schnerr, G.H., Thalhamer, M., Förster, M.:
    Shock and Wave Dynamics in Cavitating Compressible Liquid Flows in Injection Nozzles.
    Journal of Shock Waves (Springer), DOI 10.1007/s00193-008-0185-3 (2009)
  • Schnerr, G.H., Sezal, I.H., Schmidt, S.J.:
    Numerical Investigation of Three-dimensional Cloud Cavitation with Special Emphasis on Collapse Induced Shock Dynamics.
    Physics of Fluids, Vol. 20, Issue 4, 040703 (2008)

Buchartikel

  • Schmidt, S. J., M. S. Mihatsch, M. Thalhamer and N. A. Adams:
    Assessment of Erosion Sensitive Areas via Compressible Simulation of Unsteady Cavitating Flows Advanced Experimental and Numerical Techniques of Cavitation Erosion Prediction.
    Fluid Mechanics and Its Applications. K.-H. Kim, G. Chahine, J.-P. Franc and A. Karimi, Springer Berlin Heidelberg. (2014)
  • Adams, N. A., and Schmidt, S. J.:
    Shocks in Cavitating Flows.
    Bubble Dynamics and Shock Waves, C. F. Delale, Springer Berlin Heidelberg. 8: 235-256 (2013)
  • Thalhamer, M., Schmidt, S.J., Schnerr, G.H.:
    Numerical Simulation and Analysis of Cavitating Flows.
    InSiDE (Innovatives Supercomputing in Deutschland), Vol.8, No.1 (2010)

Konferenzen

2013

  • M.S. Mihatsch, S.J. Schmidt, N.A. Adams
    Estimation of incubation times through numerical simulation of 3-D unsteady Cavitating flows
    SHF Conference; Hydraulic Machines and Cavitation /Air in Water Pipes; Grenoble, France (2013)
  • C. P. Egerer, S. Hickel, S. J. Schmidt, N. A. Adams
    Analysis of turbulent cavitating flow in a micro-channel
    SHF Conference; Hydraulic Machines and Cavitation /Air in Water Pipes; Grenoble, France (2013)
  • F. Örley, M. Grilli, S. Hickel, S. Schmidt and N.A. Adams
    Application of Immersed Boundary Methods for the Investigation of Cavitating Liquid Flows Interacting with Moving Geometries
    Proceedings of the EUROMECH COLLOQUIUM 549: Immersed Boundary Methods: Current Status and Future Research Directions; Leiden, The Netherlands (2013)

2012

  • Egerer, C.P., Hickel, S., Schmidt, S.J., Adams, N.A.:
    Turbulence Modulation by Phase Change in a Cavitating Shear Layer
    Proc. 9th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements; 6-8 June 2012; Thessaloniki, Greece (2012)
  • Egerer, C.P., Hickel, S., Schmidt, S.J., Adams, N.A.:
    Implicit large-eddy simulation of cavitation in a turbulent shear layer
    Proceedings of the Eighth International Symposium on Cavitation (CAV 2012); C.-D. Ohl, E. Klaseboer, S.W. Ohl, S.W. Gong and B.C. Khoo (Eds.). ISBN: 978-981-07-2826-7 (2012)
  • Mihatsch, M., Schmidt, S.J, Thalhamer, M., Adams, N.A..:
    Quantitative Prediction of Erosion Aggressiveness through Numerical Simulation of 3-D Unsteady Cavitating Flows
    Proceedings of the Eighth International Symposium on Cavitation (CAV 2012); C.-D. Ohl, E. Klaseboer, S.W. Ohl, S.W. Gong and B.C. Khoo (Eds.). ISBN: 978-981-07-2826-7 (2012)
  • Thalhamer, M., Schmidt, S.J., Mihatsch, M., Adams, N.A.:
    Numerical simulation of sheet and cloud cavitation and detection of cavitation erosion
    Proc. ISROMAC-14, Hawai (2012)

2011

  • Mihatsch, M., Schmidt, S.J, Thalhamer, M., Adams, N.A..:
    Numerical Prediction of Erosive Collapse Events in Unsteady Compressible Cavitating Flows
    Proc. Marine 2011, International Conference on Computational Methods in Marine Engineering, Barcelona (2011)
  • Hickel, S., Mihatsch, M., Schmidt, S.J.:
    Implicit Large Eddy Simulation of Cavitation in Micro Channel Flows.
    Proc. WIMRC Cavitation Forum 2011, e-publication, July 4 - 6, 2011, Warwick, UK, (2011)
  • Skoda, R., Iben, U., Morozov, A., Mihatsch, M., Schmidt, S.J, Adams, N.A..:
    Numerical Simulation of Collapse Induced Shock Dynamics for the Prediction of the Geometry, Pressure and Temperature Impact on the Cavitation Erosion in Micro Channels.
    Proc. WIMRC Cavitation Forum 2011, e-publication, July 4 - 6, 2011, Warwick, UK, (2011)
  • Mihatsch, M., Schmidt, S.J, Thalhamer, M., Adams, N.A., Skoda, R., Iben, U.:
    Collapse Detection in Compressible 3-D Cavitating Flows and Assessment of Erosion Criteria.
    Proc. WIMRC Cavitation Forum 2011, e-publication, July 4 - 6, 2011, Warwick, UK, (2011)
  • Schmidt, S.J, Mihatsch, M., Thalhamer, M., Adams, N.A.:
    Assessment of the Prediction Capability of a Thermodynamic Cavitation Model for the Collapse Characteristics of a Vapor-Bubble Cloud.
    Proc. WIMRC Cavitation Forum 2011, e-publication, July 4 - 6, 2011, Warwick, UK, (2011)

2010

  • Delale, C.F., Baskaya, Z., Schmidt, S.J.:
    Non-Barotropic Models of Cavitation and Their Applications.
    Proc. ICMF 2010 International Conference on Multiphase Flow, Tampa, Florida, USA, 30.5. -4.6.2010, paper no: DelaleBS-ICMF2010, CD-ROM publication, (2010)

2009

  • Delale, C.F., Baskaya, Z., Schmidt, S.J., Schnerr, G.H.:
    Unsteady Bubbly Cavitating Nozzle Flows.
    Proc. 7th CAV 2009 - 7th International Symposium on Cavitation, Ann Arbor, Michigan, USA, 16.8.- 21.8.2009, paper 18, CD-ROM publication, (2009)
  • Schmidt, S.J., Thalhamer, M., Schnerr, G.H.:
    Inertia Controlled Instability and Small Scale Structures of Sheet and Cloud Cavitation.
    Proc. 7th CAV 2009 - 7th International Symposium on Cavitation, Ann Arbor, Michigan, USA, 16.8.- 21.8.2009, paper 17, CD-ROM publication, (2009)
  • Schmidt, S.J., Thalhamer, M., Schnerr, G.H.:
    Density Based CFD-Techniques for Simulation of Cavitation Induced Shock Emission.
    Proc. 8th ETC 2009 - 8th European Turbomachinery Conference, Graz, Austria, 23.3.- 27.3.2009, pp. 197-208, (2009)

2008

  • Schmidt, S.J., Sezal, I.H., Schnerr, G.H., Thalhamer, M.:
    Riemann Techniques for the Simulation of Compressible Liquid Flows with Phase-transition at all Mach numbers - Shock and Wave Dynamics in Cavitating 3-D Micro and Macro Systems.
    46th AIAA Aerospace Sciences Meeting and Exhibit, January 7 - 10, 2008, Reno, Nevada, USA, AIAA paper 2008-1238, (2008)
  • Schmidt, S.J., Sezal, I.H., Schnerr, G.H., Thalhamer, M.:
    Numerical Analysis of Shock Dynamics for Detection of Erosion Sensitive Areas in Complex 3-D Flows.
    Proc. WIMRC Cavitation Forum 2008, pp. 107-120, July 7 - 9, 2008, Warwick, UK, (2008)

2007

  • Schmidt, S.J., Sezal, I.H., Schnerr, G.H., Thalhamer, M.:
    Shock Waves as Driving Mechanism for Cavitation Erosion.
    Proc. 8th ISAIF - International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows, Lyon, France, July 2-6, 2007 (eds. Ottavy, X., Trebinjac, I.), paper ISAIF8-0044, pp. 931-940, (2007)
  • Schmidt, S.J., Sezal, I.H., Schnerr, G.H., Thalhamer, M., Förster, M.:
    Compressible Simulation of Liquid/Vapor Two-phase Flows with Local Phase Transition.
    Proc. ICMF 2007 - International Conference on Multiphase Flow, Leipzig, Germany, July 9-13, 2007 (ed. Sommerfeld, M.), paper S7_Tue_D_26, CD-ROM publication, (2007)
  • Sezal, I.H., Schmidt, S.J., Schnerr, G.H., Thalhamer, M., Förster, M.:
    Shock and Wave Dynamics in Fuel Injection Systems.
    Proc. ISSW26 2007 - 26th International Symposium on Shock Waves, Göttingen, Germany, July 15-20, 2007 (ed. in chief Hannemann, K.), CD-ROM publication, (2007)
  • Schnerr, G.H., Sezal, I.H., Schmidt, S.J.:
    Numerical Investigation of 3-D Cloud Cavitation with Special Emphasis on Collapse Induced Shock Dynamics.
    Proc. IUTAM Symposium on Recent Advances in Multiphase Flows: Numerical and Experimental, Istanbul, Turkey, June 11-14, (2007)

2006

  • Schmidt, S., Sezal, I., Schnerr, G.H.:
    Compressible Simulation of High-Speed Hydrodynamics with Phase Change.
    Proc. ECCOMAS CFD 2006 - European Conference on Computational Fluid Dynamics, Egmond aan Zee, The Netherlands, September 5-8 (eds. Wesseling, P., Onate, E., Périaux, J.), CD-ROM Publication, (2006)
  • Schnerr, G.H., Schmidt, S., Sezal, I., Thalhamer, M.:
    Shock and Wave Dynamics in Compressible Liquid Flows with Emphasis on Unsteady Load on Hydrofoils and on Cavitation in Injection Nozzles.
    Invited Lecture
    Proc. CAV2006 - 6th International Symposium on Cavitation, Wageningen, The Netherlands, September 11-15, 2006 (ed. Kuiper, G.), CD-ROM publication, (2006)