Abstract
Original language  English 

Qualification  Doctor Degree 
Awarding Institution 

Supervisors/Advisors 

Award date  27 Nov 2009 
Place of Publication  Espoo 
Publisher  
Print ISBNs  9789513873677 
Electronic ISBNs  9789513873684 
Publication status  Published  2009 
MoE publication type  G5 Doctoral dissertation (article) 
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Keywords
 twofluid model
 twophase flow
 interface heat transfer
 interface friction
 wall heat transfer
 boiling crisis
 noncondensable gas
 dissolved gas
 counter current flow limitation
 discreatization
 validation
 supercritical pressure
 nuclear power plant
 APROS
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Research output: Thesis › Dissertation › Collection of Articles
TY  THES
T1  Phenomenological extensions to APROS sixequation model. Noncondensable gas, supercritical pressure, improved CCFL and reduced numerical diffusion for scalar transport calculation
T2  Dissertation
AU  Hänninen, Markku
N1  Project code: 32753
PY  2009
Y1  2009
N2  This thesis focuses on the development of the twofluid model of the APROS simulation program. The system of constitutive equations and how equations are related to basic equations have been presented and discussed. The new noncondensable gas model, which was implemented to the twofluid model, has been described in detail. The extension of the noncondensable gas model to the twofluid system and the validation of the model have also been presented. The changes made to the sixequation model when the model has been applied to supercritical pressure calculation have been depicted. Finally, the author describes how the whole complicated system is verified and validated. Through the simulations, the applicability of the twophase model for the analyses of real plant applications is substantiated and verified. In addition to this summary, the thesis consists of four publications. The first paper deals with how the CCFL (Counter Current Flow Limitation) correlations have been implemented to the code and how these correlations have been verified. In the second paper, the noncondensable gas model and its implementation to the twofluid model have been presented. The third paper describes how the sharp temperature distribution can be maintained in the liquid flow through the aid of simple higher order discretization. In the fourth paper, the modifications carried out to the twofluid model when applied to the calculation of the supercritical pressure flow are described and discussed.
AB  This thesis focuses on the development of the twofluid model of the APROS simulation program. The system of constitutive equations and how equations are related to basic equations have been presented and discussed. The new noncondensable gas model, which was implemented to the twofluid model, has been described in detail. The extension of the noncondensable gas model to the twofluid system and the validation of the model have also been presented. The changes made to the sixequation model when the model has been applied to supercritical pressure calculation have been depicted. Finally, the author describes how the whole complicated system is verified and validated. Through the simulations, the applicability of the twophase model for the analyses of real plant applications is substantiated and verified. In addition to this summary, the thesis consists of four publications. The first paper deals with how the CCFL (Counter Current Flow Limitation) correlations have been implemented to the code and how these correlations have been verified. In the second paper, the noncondensable gas model and its implementation to the twofluid model have been presented. The third paper describes how the sharp temperature distribution can be maintained in the liquid flow through the aid of simple higher order discretization. In the fourth paper, the modifications carried out to the twofluid model when applied to the calculation of the supercritical pressure flow are described and discussed.
KW  twofluid model
KW  twophase flow
KW  interface heat transfer
KW  interface friction
KW  wall heat transfer
KW  boiling crisis
KW  noncondensable gas
KW  dissolved gas
KW  counter current flow limitation
KW  discreatization
KW  validation
KW  supercritical pressure
KW  nuclear power plant
KW  APROS
M3  Dissertation
SN  9789513873677
T3  VTT Publications
PB  VTT Technical Research Centre of Finland
CY  Espoo
ER 