Depressurization of Vertical Pipe with Temperature Gradient Modeled with WAHA Code

The subcooled decompression under temperature gradient experiment performed by Takeda and Toda in 1979 has been reproduced using the in-house code WAHA version 3. The sudden blowdown of a pressurized water pipe under temperature gradient generates a travelling pressure wave that changes from decompr...

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Main Authors: Oriol Costa, Iztok Tiselj, Leon Cizelj
Format: Article
Language:English
Published: Wiley 2012-01-01
Series:Science and Technology of Nuclear Installations
Online Access:http://dx.doi.org/10.1155/2012/951923
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author Oriol Costa
Iztok Tiselj
Leon Cizelj
author_facet Oriol Costa
Iztok Tiselj
Leon Cizelj
author_sort Oriol Costa
collection DOAJ
description The subcooled decompression under temperature gradient experiment performed by Takeda and Toda in 1979 has been reproduced using the in-house code WAHA version 3. The sudden blowdown of a pressurized water pipe under temperature gradient generates a travelling pressure wave that changes from decompression to compression, and vice versa, every time it reaches the two-phase region near the orifice break. The pressure wave amplitude and frequency are obtained at different locations of the pipe's length. The value of the wave period during the first 20 ms of the experiment seems to be correct but the pressure amplitude is overpredicted. The main three parameters that contribute to the pressure wave behavior are: the break orifice (critical flow model), the ambient pressure at the outlet, and the number of volumes used for the calculation. Recent studies using RELAP5 code have reproduced the early pressure wave (transient) of the same experiment reducing the discharge coefficient and the bubble diameter. In the present paper, the long-term pipe pressure, that is, 2 seconds after rupture, is used to estimate the break orifice that originates the pressure wave. The numerical stability of the WAHA code is clearly proven with the results using different Courant numbers.
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spelling doaj-art-d04f6faabd3e456aa028ec32a06866f12025-08-20T02:20:03ZengWileyScience and Technology of Nuclear Installations1687-60751687-60832012-01-01201210.1155/2012/951923951923Depressurization of Vertical Pipe with Temperature Gradient Modeled with WAHA CodeOriol Costa0Iztok Tiselj1Leon Cizelj2Reactor Engineering Division, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, SloveniaReactor Engineering Division, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, SloveniaReactor Engineering Division, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, SloveniaThe subcooled decompression under temperature gradient experiment performed by Takeda and Toda in 1979 has been reproduced using the in-house code WAHA version 3. The sudden blowdown of a pressurized water pipe under temperature gradient generates a travelling pressure wave that changes from decompression to compression, and vice versa, every time it reaches the two-phase region near the orifice break. The pressure wave amplitude and frequency are obtained at different locations of the pipe's length. The value of the wave period during the first 20 ms of the experiment seems to be correct but the pressure amplitude is overpredicted. The main three parameters that contribute to the pressure wave behavior are: the break orifice (critical flow model), the ambient pressure at the outlet, and the number of volumes used for the calculation. Recent studies using RELAP5 code have reproduced the early pressure wave (transient) of the same experiment reducing the discharge coefficient and the bubble diameter. In the present paper, the long-term pipe pressure, that is, 2 seconds after rupture, is used to estimate the break orifice that originates the pressure wave. The numerical stability of the WAHA code is clearly proven with the results using different Courant numbers.http://dx.doi.org/10.1155/2012/951923
spellingShingle Oriol Costa
Iztok Tiselj
Leon Cizelj
Depressurization of Vertical Pipe with Temperature Gradient Modeled with WAHA Code
Science and Technology of Nuclear Installations
title Depressurization of Vertical Pipe with Temperature Gradient Modeled with WAHA Code
title_full Depressurization of Vertical Pipe with Temperature Gradient Modeled with WAHA Code
title_fullStr Depressurization of Vertical Pipe with Temperature Gradient Modeled with WAHA Code
title_full_unstemmed Depressurization of Vertical Pipe with Temperature Gradient Modeled with WAHA Code
title_short Depressurization of Vertical Pipe with Temperature Gradient Modeled with WAHA Code
title_sort depressurization of vertical pipe with temperature gradient modeled with waha code
url http://dx.doi.org/10.1155/2012/951923
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AT iztoktiselj depressurizationofverticalpipewithtemperaturegradientmodeledwithwahacode
AT leoncizelj depressurizationofverticalpipewithtemperaturegradientmodeledwithwahacode