This is NKS NKS-R NKS-B News Seminars NKS Reports Phantom Library

You are here: Homepage NKS Reports View document

List all reports List all NKS-R reports List all NKS-B reports Search Reports  
NKS Programme Area:NKS-R
Research Area:Thermo hydraulics
Report Number:NKS-169
Report Title:CFD Simulation of Air Discharge Tests in the PPOOLEX Facility
Activity Acronym:POOL
Authors:Vesa Tanskanen, Markku Puustinen
Abstract:This report summarizes the CFD simulation results of two air discharge tests of the characterizing test program in 2007 with the scaled down PPOOLEX facility. Air was blown to the dry well compartment and from there through a DN200 blowdown pipe into the condensation pool (wet well). The selected tests were modeled with Fluent CFD code. Test CHAR-09-1 was simulated to 28.92 seconds of real time and test CHAR-09-3 to 17.01 seconds. The VOF model was used as a multiphase model and the standard k ε-model as a turbulence model. Occasional convergence problems, usually at the beginning of bubble formation, required the use of relatively short time stepping. The simulation time costs threatened to become unbearable since weeks or months of wall-clock time with 1-2 processors were needed. Therefore, the simulated time periods were limited from the real duration of the experiments. The results obtained from the CFD simulations are in a relatively good agreement with the experimental results. Simulated pressures correspond well to the measured ones and, in addition, fluctuations due to bubble formations and break-ups are also captured. Most of the differences in temperature values and in their behavior seem to depend on the locations of the measurements. In the vicinity of regions occupied by water in the experiments, thermocouples getting wet and drying slowly may have had an effect on the measured temperature values. Generally speaking, most temperatures were simulated satisfyingly and the largest discrepancies could be explained by wetted thermocouples. However, differences in the dry well and blowdown pipe top measurements could not be explained by thermocouples getting wet. Heat losses and dry well / wet well heat transfer due to conduction have neither been estimated in the experiments nor modeled in the simulations. Estimation of heat conduction and heat losses should be carried out in future experiments and they should be modeled in future simulations, too. Key words
Keywords:Condensation pool; air discharge; non-condensable gas; CFD simulation
Publication date:01 Jul 2008
ISBN:ISBN: 978-87-7893-234-1
Number of downloads:2691
Download:pdf NKS-169.pdf
Contact NKS   NKS Sekretariatet
Boks 49
DK-4000 Roskilde
  Telephone +45 46 77 40 41
E-mail: nks@nks.org 
 

Address for visitors
Directions and map

Privacy Policy

Website last modified: 23 January 2019