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Temperature Fluctuations in Fluid and Pipe Walls induced by Turbulent Mixing

Titel Englisch Temperature Fluctuations in Fluid and Pipe Walls induced by Turbulent Mixing
Gesuchsteller/in Prasser Horst-Michael
Nummer 132659
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Institut für Energietechnik ETH Zürich
Hochschule ETH Zürich - ETHZ
Hauptdisziplin Technische Physik
Beginn/Ende 01.02.2011 - 31.01.2015
Bewilligter Betrag 238'857.00
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Alle Disziplinen (2)

Disziplin
Technische Physik
Fluiddynamik

Keywords (10)

turbulent mixing; temperature fluctuations; tee junctions; thermal fatigue; RANS; temperature fluctuation transport model; wire-mesh sensors; parallel; Reynolds Averaged Navier Stokes;

Lay Summary (Englisch)

Lead
Lay summary
Lead: Turbulent mixing of streams with different temperature may result in significant temperature fluctuations in the walls of pipes and other components of power plants or other industrial installations. These fluctuations may cause thermal fatigue in the wall material and pose the risk of a failure of the component. Method: The proposed project is focused on the prediction of temperature fluctuations in a T-junction. It is planned to apply Reynolds Averaged Navier-Stokes (RANS) modeling as an alternative to very computational expensive LES simulations. RANS modeling will be extended by temperature fluctuation transport equations. It is based on a second averaging of the scalar transport equation, which results in additional transport equations for the RMS of the temperature, and turbulent heat fluxes. This approach reduces computational costs compared to LES by orders of magnitude. Still, it is possible to obtain distributions of the RMS of the fluid temperature. For a subsequent fatigue analysis, estimates of the temperature fluctuations in the wall and their frequency range are needed. The feasibility of methods for an approximate determination of the time scale of turbulent mixing patterns found in the fluid and a simplified modeling of the response of the temperature field in the wall will be explored. For the experimental part, a co-operation with the Laboratory of Nuclear Power (IKE) of the University of Stuttgart will be established. IKE has started to construct a T-junction experiment operating parameters of an original nuclear power plant. We will construct a second test facility to perform complementary mixing experiments at room temperature respecting fluid dynamic similarity. Mesh sensor techniques provide two-dimensional distributions of the transport scalar with a time resolution of up to 10 kHz for the support of the model development. Aim: The main outcome of the project is an efficient method for the prediction of temperature fluctuations in components, where fluid streams of different temperature are mixed. This phenomenon has a relevant impact to the lifetime of components of nuclear power plants and other industrial installations. The results will therefore contribute to economy and safety of these plants. The fast-running RANS simulations aim at performing preliminary screenings of components to identify locations of critical amplitudes of temperature fluctuations, especially in complex, large-scale geometries. Locations with critical amplitudes of temperature fluctuations can be identified and a more detailed research using time-consuming LES methods or dedicated experiments can be focused to relevant cases.
Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Publikationen

Publikation
Large Eddy Simulation of Turbulent Penetration in a T-junction
(2014), Large Eddy Simulation of Turbulent Penetration in a T-junction, in International Congress on Advances in Nuclear Power Plants (ICAPP 2014), Charlotte, U.S.A..
The Influence of Density Stratification and T-junction Geometry on Turbulent Penetration
(2014), The Influence of Density Stratification and T-junction Geometry on Turbulent Penetration, in International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10), Okinawa, Japan.
Turbulent Penetration in T-junction Branch Lines with Leakage Flow
(2014), Turbulent Penetration in T-junction Branch Lines with Leakage Flow, in Nuclear Engineering and Design, 276, 43-53.
Steady State RANS Simulations of Temperature Fluctuation in a Single Phase Turbulent Mixing
(2012), Steady State RANS Simulations of Temperature Fluctuation in a Single Phase Turbulent Mixing, in International Congress on Advances in Nuclear Power Plants 2012, ICAPP 2012, Chicago, USA.
Turbulent Penetration as a Thermal Fatigue Problem in low Side Flow T-Junctions
(2012), Turbulent Penetration as a Thermal Fatigue Problem in low Side Flow T-Junctions, in Nuclear Thermal Hydraulics and Safety 8 (NTHAS8) , Beppu, Japan.
Wire Mesh Sensor for High Temperature High Pressure Applications
, Wire Mesh Sensor for High Temperature High Pressure Applications, in 16th International Topical Meeting on Nuclear Reactor Thermalhydraulics (NURETH-16), Chicago, USA.

Zusammenarbeit

Gruppe / Person Land
Formen der Zusammenarbeit
Swissnuclear Schweiz (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Industrie/Wirtschaft/weitere anwendungs-orientierte Zusammenarbeit
Paul Scherrer Institut, NES, LTH Schweiz (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Forschungsinfrastrukturen
Universität Stuttgart, IKE Deutschland (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Forschungsinfrastrukturen

Wissenschaftliche Veranstaltungen

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
Experimental and Computational Multiphase Flow Group (NERS) Einzelvortrag The Influence of Density Stratification and T-junction Geometry on Turbulent Penetration 10.03.2015 University of Michigan, Vereinigte Staaten von Amerika Kickhofel John Louis;
1 day workshop at the CAMS Einzelvortrag Turbulent Penetration as a Thermal Fatigue Problem in Nuclear Power Plants 17.11.2013 Center for Advanced Mathematical Sciences, American University of Beirut, Libanon Kickhofel John Louis;
American Nuclear Society Summer Meeting Einzelvortrag Pulsating Turbulent Penetration in T-junction Mixing Experiments 18.06.2013 Atlanta, GA, Vereinigte Staaten von Amerika Kickhofel John Louis;
Thermal Hydraulics of Innovative Nuclear Systems (THINS) Cluster Workshop 2 Einzelvortrag Turbulent Penetration in T-Junctions 07.02.2013 Royal Institute of Technology (KTH), Stockholm, Schweden Kickhofel John Louis;
Seminar INSS Japan Einzelvortrag High Temperature and Pressure Wire Mesh Sensor 20.12.2012 Institute of Nuclear Safety System Incorporated, Fukui, Japan Kickhofel John Louis;
SwissNuclear "Tag der Forschung" Einzelvortrag Temperature Fluctuations in Fluid and Pipe Walls induced by Turbulent Mixing 08.05.2012 Gösgen Nuclear Power Plant, Schweiz Kickhofel John Louis; Prasser Horst-Michael;


Selber organisiert

Titel Datum Ort
Joint one-day workshop on two-phase instrumentation with Prof. Kikura from TokyoTech, Japan 25.08.2014 ETH Zurich, Schweiz

Auszeichnungen

Titel Jahr
Best student paper award for the conference paper: John Kickhofel, Horst-Michael Prasser, Karthick Selvam, Eckart Laurien, Hermann Huber: MESH SENSOR FOR HIGH TEMPERATURE HIGH PRESSURE APPLICATIONS. NURETH-16, Chicago, IL, August 30-September 4, 2015, proceedings p. 841. Doted financially with 500 USD. 2015

Patente

Titel Datum Nummer Erfinder Eigentümer
Grid Sensor Package ("provisional" European Patent Application) 16.12.2014 EP14198142

Verbundene Projekte

Nummer Titel Start Förderungsinstrument
141025 Turbulent Mixing of Two Gas Streams with High Density Ratio 01.09.2012 Projektförderung (Abt. I-III)

Abstract

Turbulent mixing of streams with different temperature may cause significant temperature fluctuations in the walls of pipes and other components of power plants or other industrial installations. These fluctuations may cause thermal fatigue in the wall material and pose a risk to the safety and reliability of the plant. The proposed project is focused on the prediction of temperature fluctuations in a T-junction by techniques of experimental simulation and a contribution to the theoretical prediction for arbitrary geometries by means of an extension and validation of Reynolds Averaged Navier-Stokes (RANS) modeling. For the experimental part, a co-operation with the Laboratory of Nuclear Power (IKE) of the University of Stuttgart will be established. IKE has started to develop and construct a T-junction experiment that will provide measuring data on the velocity and temperature fields inside the flow domain at operating parameters of an original nuclear power plant for the first time. High parameters pose a number of limitations to the applicability of measuring methods. For this reason, temperature information will be obtained only at a limited number of locations by the use of thermocouples. It is therefore proposed to construct a second test facility, the test geometry of which is an identical copy of the IKE T-junction to perform mixing experiments at room temperature. Mesh sensor techniques based on detection of electrical conductivity will be used instead of thermocouples. These sensors provide two-dimensional distributions of the transport scalar at hundreds of individual measuring positions with a time resolution of up to 10 kHz and are from this point o view extremely superior to thermocouples. The temperature as transport scalar is simulated by an addition of a tracer salt that increases the electrical conductivity of the fluid. In this way, mixing patterns become visible to mesh sensors. As an alternative, it is planned to detect temperature fluctuations directly via the temperature dependency of the electrical conductivity of water, which is less accurate but opens to door to non-adiabatic tests at the cold, non-pressurized test rig. Beside flow instrumentation, the IKE T-junction is equipped with strain gauges, too. Tests will be performed until failure of the tested component, which allows mechanical testing of the fragments. It is a considerable added value of the proposed exchange of experimental results that also the data of the structural behavior will be made available to the Swiss partner. The theoretical part of the proposed PhD project aims at predicting temperature fluctuations by means of steady-state RANS simulations. This is interesting from a practical point of view: LES, which has been found to be the ideal tool to predict the temperature fluctuations, becomes too expensive when more complex and larger geometries typical for industrial plants have to be analyzed. In previous work, it has been demonstrated that solving Reynolds stress equations coupled with a transport equation for the temperature fluctuations reduce computational costs compared to LES by orders of magnitude. Still, with this technique it is possible to obtain distributions of the RMS of the fluid temperature. It is the task of the PhD student to perform numerical simulations aiming at a validation of this model and to explore possibilities for assessing the resulting temperature fluctuations in the wetted wall, as well as their characteristic frequency range.
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