Benchmarking of the one-dimensional one-group interfacial area transport equation for reduced-gravity bubbly flows

2009 ◽  
Vol 35 (4) ◽  
pp. 323-334 ◽  
Author(s):  
S. Vasavada ◽  
X. Sun ◽  
M. Ishii ◽  
W. Duval
Author(s):  
Deoras Prabhudharwadkar ◽  
Chris Bailey ◽  
Martin Lopez de Bertodano ◽  
John R. Buchanan

This paper describes in detail the assessment of the CFD code CFX to predict adiabatic liquid-gas two-phase bubbly flow. This study has been divided into two parts. In the first exercise, the effect of Lift Force, Wall Force and the Turbulent Diffusion Force have been assessed using experimental data from the literature for air-water upward bubbly flows through a pipe. The data used here had a characteristic near wall void peaking which was largely influenced by the joint action of the three forces mentioned above. The simulations were performed with constant bubble diameter assuming no bubble interactions. This exercise resulted in selection of the most appropriate closure form and closure coefficients for the above mentioned forces for the range of flow conditions chosen. In the second exercise, the One-Group Interfacial Area Transport equation was introduced in the two-fluid model of CFX. The interfacial area density plays important role in the correct prediction of interfacial mass, momentum and energy transfer and is affected by bubble breakup and coalescence processes in adiabatic flows. The One-Group Interfacial Area Transport Equation (IATE) has been developed and implemented for one-dimensional models and validated using cross-sectional area averaged experimental data over the last decade by various researchers. The original one-dimensional model has been extended to multidimensional flow predictions in this study and the results are presented in this paper. The paper also discusses constraints posed by the commercial CFD code CFX and the solutions worked out to obtain the most accurate implementation of the model.


2010 ◽  
Vol 2010 ◽  
pp. 1-19 ◽  
Author(s):  
Xia Wang ◽  
Xiaodong Sun

An interfacial area transport equation (IATE), proposed to dynamically describe the interfacial structure evolution of two-phase flows, could help improve the predictive capability of the two-fluid model. The present study aims to investigate the well-posedness issue of a one-dimensional two-fluid model with the IATE (named “two-fluid-IATE model” hereafter) using a characteristic analysis. The momentum flux parameters, which take into account the coupling of the volumetric fraction of phase and velocity distributions over the cross-section of a flow passage, are employed. A necessary condition for the system to achieve hyperbolicity under an adiabatic flow condition is identified. A case study is performed for an adiabatic liquid-liquid slug flow, which shows that the hyperbolicity of the two-fluid-IATE model is guaranteed if appropriate correlations of the momentum flux parameters are applied in the two-fluid-IATE model.


AIAA Journal ◽  
2009 ◽  
Vol 47 (5) ◽  
pp. 1123-1131 ◽  
Author(s):  
Takashi Hibiki ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
Mamoru Ishii

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