MSC.Marc 2003 - National Energy Technology Laboratory Library/Research/Coal/energy systems... ·...
Transcript of MSC.Marc 2003 - National Energy Technology Laboratory Library/Research/Coal/energy systems... ·...
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ContentsMeshing/RemeshingAnalysis of Composite Materials (shell/solid)Fracture Mechanics CapabilitiesHeat Transfer and Coupled Thermal StressesRunning Jobs in ParallelFluidsUser Subroutines Future Work PEN Fuel Cell Modeling
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CapabilitiesSteady State SimulationTransient Simulation Temperatures can be easily used in uncoupled thermal stress analysisCoupled Thermal-Structural AnalysisCoupled Thermal-Electric (Joule Heating) Coupled Thermal-Electric-Structural Choice of Time Step Procedures
Fixed Time StepsAdaptive Time Steps
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Capabilities1-d2-d (planar and axisymmetric solid and axisymmetric shells)3-d (solid, and shells)Heat transfer shells may have any number of layers, temperature varies either linearly or quadratically through layerNonlinear Transient Cyclic SymmetryAll heat transfer elements have comparable structural elements for thermal stress analysis or coupled analysis
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Capabilities
Isotropic , Orthotropic or Anisotropic thermal properties.
All properties may be function of temperature.
Latent heat effects included to model phase changes
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Capabilities
Point or Distributed FluxesConvective Boundary ConditionsRadiative HeatingView Factor Calculations efficiently done using Monte Carlo methodInternal Heating due to plasticity or friction in coupled structural analysis.Thermal Contact in coupled structural analysis.
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Applications
Energy IndustryEngines (Gas Turbine, Diesel, Automotive)RocketsElectronicsFire SafetyManufacturing Welding
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Channel
Special Modeling techniques to represent fluid flow in channels
Special modeling techniques to model convection and radiation across small gaps.
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Computationally Efficient Solution Methods
Direct Sparse Solvers
Iterative Solvers
Parallel Processing using Domain Decomposition
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Turbine Blade Structural Analysis
Number of Domains: 4Number of Elements: 72KDegrees of Freedom: 55KScaling: 4.2X
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Thermal Contact
If dist < d1 then thermal conduction
If d1< dist < d2 then simplified thermal radiation
If d2 < dist then no contact
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Near Contact
ConvectionNatural convectionRadiationDistance dependent convection
Q = hcv*(T2-T1)+hnt*(T2-T1)ent +sigma*eps*(T24-T14) +
(hct – (hct-hbl)*gap/dqnear)*(T2-T1)
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Thermal Contact InputHct – contact thermal coefficientHcve – environment thermal coefficientTsink – sink temperatureHcv – near convective coefficientHnc – near natural convection coefficientBnc – exponent for natural convectionEm – emissivityHbl – lower limit of distance dependent convection coeffDqnear – distance below which near thermal behavior is applied
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Coupled Joule Heating
Weak coupling between mechanical, thermal, and electrical fieldsTypical application: high voltage electrical switchElectronic circuits
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Fluid –Thermal Analysis
Navier Stokes Finite Element Procedure UsedTightly Coupled AnalysisIncompressible FluidLaminar FlowNewtonian or Non-Newtonian Fluid2D or 3D fluid flow with any type of elementForced or Free Convection
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Fluid-Thermal Applications
Electronic PackagingQuenchingFuel Cells
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Super Scalable Parallel
Linux cluster of 4 HP workstation xL-class with two of Intel's® Pentium® III 1GHz processors and 4GB of RAM/CPU
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Proposed DevelopmentTo develop a customized graphical user interface for fuel cell stacks. To integrate an EC module currently used by PNNL into MSC.Marc to be able to analyze the thermal stresses arising as a consequence of the heat production due to chemical reaction in the fuel cell and heat transfer due to convection effects.To conduct a feasibility study of the accuracy and efficiency of MSC.Marc for simulating flow fields in a typical fuel cell stack and to use the results of this feasibility study to determine areas of possible improvement in MSC.Marc’s fluid capabilities.
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Fuel Cell Layer ConfigurationThe following slides show the layers of a typical planar fuel cell design.In the example design, the layers stack up to make up air and fuel flow channels on each side of the PEN.The PEN has 3 layers, Cathode (air-side), Electrolyte, and Anode (fuel-side). The center area (inside where the PEN seals to the picture-frame) is where the electrochemistry occurs.The following slides show “footprints” of the various layers (the selected areas show in the blue-green color).The layers are listed in the order from the interconnect (conductive layer between stacked cells), to the cathode-side layers,the PEN, anode-side layers, to the interconnect on the anode-side.The last 2 slides show the layers from bottom (cathode) and top (anode) views with the interconnect layers removed.The flow/ heat transfer/EC/stress model must have the necessary connectivity through all these layers, including through the flow channels where no mesh is shown in the last 2 slides.
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PenInactiveArea,
Pen-to-PictureframeSeal
(both sameFootprint)
PEN Inactive Area
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PEN ActiveArea
PEN In-ActiveArea
AnodeSpacer (green)
Anode spacer-to-interconnect seal
Assembly
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Seal Temperature Profiles
1
2
3
4
Pen Seal Temperature
960
980
1000
1020
1040
1060
1080
1100
0.00 0.02 0.04 0.06 0.08 0.10 0.12
Path length (m)
Seal
Str
ess,
Pa
Side 1Side 2Side 3Side 4
Glass Seal Temperature
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Through Thickness Stress
Through Thickness Seal Stress - Side 1
0.0E+00
1.0E+06
2.0E+06
3.0E+06
4.0E+06
5.0E+06
6.0E+06
7.0E+06
8.0E+06
9.0E+06
1.0E+07
0.00 0.02 0.04 0.06 0.08 0.10 0.12Path length (m)
Seal
Str
ess,
Pa
Baseline Seal3-Elements in Seal layerEseal=Eglass/10Manifold Ligaments RemovedSeal Thickness = 2 x Baseline
Shear Stress in Width Direction - Side 1
0.0E+00
5.0E+05
1.0E+06
1.5E+06
2.0E+06
2.5E+06
3.0E+06
3.5E+06
4.0E+06
0.00 0.02 0.04 0.06 0.08 0.10 0.12Path length (m)
Seal
Str
ess,
Pa
Baseline Seal3-Elements in Seal layerEseal=Eglass/10Manifold Ligaments RemovedSeal Thickness = 2 x Baseline
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EC in FEA Framework
Fuel cell operations involve multi-physics processes; the constitutive thermal, chemical, electrochemical and transport processes are strongly coupled => requiring versatile multi-physics tool for realistic descriptionTechnology development involves design optimization of various geometric, material and operation parameters; the cost of such parametric studies increases exponentially with the number of the working parameters and there are many such parameters involved
=> Computational efficiency is critically important
MARCFlow – Thermal -
Electrical -Mechanical
STRESSES
FLUX
Heat Flux PLOTV
ELEVAREC
T, pp(i)
Cell Voltage
Gas, Chemistry,
Heat Generation
Update
State Variables
Model Geometry, Temperature, Current Distribution