GOTHIC: Overview

TL George

Numerical Applications, Inc

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GOTHIC 7.2

• General Purpose Thermal-Hydraulic Analysis

• Special Modeling Features for Containment Building Modeling

• Ongoing Development and Maintenance Support by the EPRI GOTHIC Enhancement Project (since 1993).

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Multi-Zone Modeling

• Combine Lumped and Subdivided Volumes

• Superimposed Conductors

• Finite Volume Solution

• Semi-explicit• Implicit

Thermal Conductors

Junctions

Components

LumpedVolumes

SubdividedVolume

Boundary Conditions

F

P

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Multiphase/Multicomponent

• Vapor• Steam• N Gas Components

• Drops• Liquid

• Films• Pools• Slugs

• Mist• Ice

.. .. . ... .. .

...

.. . ..

....

. ... ....

. . .. .

Pool

...

. . .. . .......

..

... .. ..

....

. ... ..

....

.... ..

Lumped

Subdivided

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Equation SetPhase Description Mass

Balance Energy Balance

Mom. Balance

Vapor Steam, gas components in bubbles or free vapor

Steam, each gas component

Yes Yes

Liquid Continuous liquid in pools, films, slugs, bubbly flow

Yes Yes Yes

Drops Small liquid particles Yes Yes Yes

Mist Very small water droplets Yes T=Tsat U=Uv

Ice Ice formation and melting on conductor surfaces

Yes Yes No

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Interphase Heat and Mass Transfer

• Evaporation• Condensation

• Diffusion Layer Model for Noncondensing Gas Effects

• Boiling/Flashing• Drop Entrainment• Drop Deposition• Ice Melt

SteamInjection

Air Bubble

CondensingSteamBubbles

Water

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Wall Heat Transfer and Condensation

• Free Convection• Forced Convection• Radiation

• Wall - Steam• Wall - Wall

• Condensation• Uchida• Tagami• Gido-Koestel• Mist/Diffusion

Layer Model 1D and 2D Conduction

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Mixing• Buoyant Flows• Forced Convection• Jet Induced Mixing• Diffusion

• Molecular• Turbulent - k-e Model• Mass Diffusion - Vapor• Thermal Diffusion -

Vapor/Liquid• Momentum Diffusion -

Vapor/Liquid

Vent

Steam Plume Source

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Hydrogen Combustion• Recombiners• Lumped Parameter

• HECTR Model• User Specified

Propagation

• Subdivided Volume• Calculated Propagation• Laminar• Turbulent

• Eddy Diffusivity Model

3D H2 Burn in a Box

Igniter

x

z

Y=0

Y=Mid

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Equipment Models• Pumps/Fans• Valves• Vacuum Breakers• Heat Exchangers• Fan Coolers• Igniters• Recombiners• Heaters/Coolers• Spray Nozzles

Controls Trips Forcing Function Control Systems

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• Networks Consist of Links and Nodes

• Full Implicit Solution• Two-phase Homogenous

Equilibrium Flow• Heat Addition/Extraction

at Nodes• Connect to

• Lumped Volumes• Subvolumes• Boundary Conditions

Piping and Duct Networks

Tank System Ventilation

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Subdivided Volumes• Volume and Area

Porosity Factors to Model Obstructions and Irregular Boundaries

• Slip/No-Slip Boundaries

• Easy User Interface

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3D Connectors

• Connect Subdivided Volumes to

• Lumped Volumes• Subdivided Volumes

• Embedded Grids• Full 3D Momentum

Solution• Diffusion Across

Connection

3D Connectors at interfacebetween coarse and finegrids.

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Multiple Detail Levels

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Advanced Wall Condensation Model• Sensible Heat Transfer

• Free Convection• Forced Convection• Radiation to Steam

• Mass Transfer• Mass Transfer

Coefficient from Heat/Mass Transfer Analogy

• Mist Formation in the Boundary Layer

Tv

Tsat

Subcooling

ym

..

.

..

.

... .... ...

.... ...

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Comprehensive Drop Behavior Models• Drop Breakup

• Hydrodynamic Forces• Flashing

• General Entrainment Model• Relative Velocity• Film/Pool Thickness• Fluid Properties

• Depositions Models• Diffusion• Turbulent Impaction• Bends

WALE Test Drop Concentration

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Solution Methods• Conductor Solution

• Full implicit finite volume

• Fluids Solution• Semi-implicit finite volume• Full-implicit finite volume• 1st and 2nd order upwind differencing options• Multigrid, Conjugate Gradient, Block Iterative

and Direct Matrix solution options.

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Applications• Heating and Cooling

• Forced Convection• Natural Convection• Radiation

• Evaporation and Condensation

• Boiling

• HVAC system performance

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Applications• EQ Analysis

• EQ Environment• Thermal Lag

• Room Heatup

• Containment Pressure and Temperature

• Line Breaks in Auxiliary Buildings

• Multiphase Flow in Piping Systems• Water Hammer

• Cooler Performance

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Applications• Hydrogen

• Distribution• Recombiners• Burn

• Spent Fuel Pool Performance• Hydrodynamic Loads on Equipment• Hazardous Gas Migration• Special Investigations …

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Assessment

• Current Test Matrix Includes 204 Tests• 96 Functional Tests• 53 Comparison with Analytic Results• 22 Separate Effects Experiments• 32 Combined Effects Experiments

• Includes 4 from International Standard Problems

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Enhancements in Progress

• Tracked component in the liquid phase• Liquid component• Solid particles with settling

• Multiple drop fiel• Parallel Processing

• Distributed computing on multinode system for faster run speed

• Additional Assessment

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Quality Assurance

• GOTHIC is maintained under NAI’s QA Program.

• Conformance to 10CFR50 Appendix B requirements.

• Meets intent of ASME NQA-1

• Built in QA features• Event Logging• File Comparison Utility

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More Information

• www.numerical.com• Animations for CFD simulations