Interaction with Universitiesand

CATHENA Water Properties

byLaurence Leung & Thomas Beuthe

Presented at the CNC-IAPWS meeting Friday, May 23 2003 COG Offices, Toronto

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COG-University Interaction

Laurence Leung

Fuel Channel Thermalhydraulics Branch

AECL

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COG-University Interaction

Arrangement Via COG project contractors (e.g., AECL)

Fundamental research topics of interest to COG Thermalhydraulics (simple tubes and annuli) Fluid properties (light water, heavy water, non-aqueous fluids)

Funding options Direct support (projects related to the nuclear industry only) Joint program with NSERC (projects related to nuclear and

other industries)

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COG-University Interaction

Benefits Cost reduction (support PDFs and grad. students only,

university covers professor’s time) Training of potential employees for the industry (most PDFs

and grad students have been employed by various organizations within the industry)

International cooperation (much easier via universities, which are non-commercialized organizations, e.g., data exchange, staff attachment)

Publicity (COG support is acknowledged in posters around the experimental facilities during university open house and tours of visitors/students from other universities and organizations)

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Fluid Properties Development

Thermalhydraulics calculations light water and heavy water Freons

Reactor safety codes and PC software applications Distribution to other parties QA issue License issue

University cooperation to develop specific properties routines using available information from open literature

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CATHENA

Thomas Beuthe

Containment and Thermalhydraulics Branch

AECL

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CATHENA

CATHENA is a Thermalhydraulic Network Analysis code.

Developed by AECL primarily for analysis of CANDU reactors.

Uses a transient, 1-D, non-equilibrium 2-fluid representation of two-phase flow in piping networks.

Thermalhydraulic model solves 6 partial differential equations for conservation of mass, momentum and energy for each phase.

Utilizes a 1st order, finite difference, semi-implicit, one-step method, not limited by material Courant number.

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HLWP

Heavy and Light Water Property routines Given P,h (CATHENA dependent variables) HLWP provides

Thermodynamic values: hl, hv ρl, ρv, T (and their derivatives w.r.t. to P at saturation), and ρl, ρv, Tl, Tv, Cpl, Cpv, ∂ρl/∂hl│P, ∂ρv/∂hv│P,

∂ρl/∂Pl│h, ∂ρv/∂Pv│h

Transport properties: sonic velocity, dynamic viscosity, thermal conductivity, surface tension.

Noncondensable Gas Properties, ideal gas property data for Air, H2, N2, Ar, He and CO2

Originally developed for CATHENA Currently also used by other AECL codes (ASSERT,

TUBRUPT)

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HLWP

Current range of applicability for water: P: 611.73 Pa – 22.046 MPa h: 0 kJ/kg – 1770 kJ/kg (liquid)

2190 kJ/kg – 7400 kJ/kg (vapour)

(above 7400 kJ/kg ideal gas law assumed,

upper limit 12,000 kJ/kg or about 4000 C)

Applicable in the liquid, vapour and metastable regions.

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HLWP

Routines use a 1-D cubic Hermite polynomial fit for thermodynamic saturation values, and a bi-quintic Hermite polynomial fit for single-phase liquid and vapour states.

Generating function used to produce fitting data was the 1984 NBS/NRC (IAPS-84) by Haar, Gallagher and Kell (H2O), and Hill’s 1981 formulation for D2O.

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HLWP

Recently, and effort was made to bring together all parties interested in HLWP within AECL to specify requirements for an updated HLWP library.

Currently, a project is underway to: Provide a useful user-interface to HLWP Update HLWP using the latest available data Increase accuracy of fit and extend range (metastable,

supercritical, dissociation?)

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Hermite fit

Internally, HLWP is fit using the values of entropy and its derivatives: s, sh, sp, shp, spp, shh, spph, shhp, spphh, where sh= ∂s/∂h

These derivates form a basis for the Hermite polynomial fit, but can also be used to derive the needed thermodynamic values as follows:

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Hermite fit

T = 1/sh

ρ = -sh/sp

Cp = -sh2/shh

∂ρ/∂h│P = (shpsh-shhsp)/sp2

∂ρ/∂P│h = (sppsh-shpsp)sp2

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Current Work

Re-fitting HLWP to latest IAPWS-95 standard. In general, current standard is smoother, more consistent, and offers ability to quote absolute accuracy.

Some interesting issues identified: “Glitch” in the saturation value of dynamic viscosity No user support for metastable regions (wild west!)

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Dynamic viscosity at saturation for liquid

4.6e-005

4.7e-005

4.8e-005

4.9e-005

5e-005

5.1e-005

5.2e-005

5.3e-005

2.1e+007 2.12e+007 2.14e+007 2.16e+007 2.18e+007 2.2e+007

Dynam

ic V

iscosity (

N s

m-2

)

Pressure (Pa)

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Dynamic viscosity at saturation for vapour

2.9e-005

3e-005

3.1e-005

3.2e-005

3.3e-005

3.4e-005

3.5e-005

3.6e-005

3.7e-005

3.8e-005

2.1e+007 2.12e+007 2.14e+007 2.16e+007 2.18e+007 2.2e+007

Dynam

ic V

iscosity (

N s

m-2

)

Pressure (Pa)

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Overview

0

500000

1e+006

1.5e+006

2e+006

2.5e+006

3e+006

100 1000 10000 100000 1e+006 1e+007 1e+008

Pre

ssu

re [P

a]

Enthalpy [J/kg]

Vapour Saturation “5%” limit

Haar practical limit

10MPa limit

IAPWS-95 Ideal Gas Spinodal

IAPWS-95 Spinodal

Bochum Practical Limit

Liquid Saturation

Haar Practical Limit

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Additional considerations

“5%” metasable vapour line (small zone!) 10MPa transition line Ideal gas to regular property transition Subcritial to supercritical transition Metastable zones: spinodals represent the absolute

limit, but what is the “reasonable” limit? (No guidance!) High temperature (dissociation!)

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Looking Ahead

Need update to D2O properties?

release rates of noncondensable gases from solution (e.g. Air, N2, H2)

decomposition rates for hydrazine and the production of noncondensable gases

absorption of noncondensable gases by water

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Conclusions

Good cooperation with universities on water properties, leaveraging the availaible resources to their best potential

Active work is proceeding to update water properties in the leading AECL property routines.

Issues identified in property generation routines: Operation of IAPWS-95 implementations in metastable

regions Stability of Bochum routines Need for smooth data (e.g. dynamic viscosity at saturation)