Nucleate Boiling Flow Simulation With Coupling of Eulerian and Lagrangian Methods

2005 ◽  
Author(s):  
Bosˇtjan Koncˇar ◽  
Ivo Kljenak ◽  
Borut Mavko
Keyword(s):  
Model Simulation ◽  
Fluid Model ◽  
Nucleate Boiling ◽  
Homogeneous Distribution ◽  
Lagrangian Simulation ◽  
Radial Profiles ◽  
Boiling Flow ◽  
Tracking Model ◽  
Two Fluid Model ◽  
Two Fluid

Subcooled boiling flow was simulated by combining the two-fluid model of the CFX-4.4 code and a Lagrangian bubble-tracking model. At present, both models are coupled “off-line” via the local bubble Sauter diameter. The two-fluid model simulation with the CFX-4.4 code provides local values of turbulent kinetic energy field of the liquid phase, which is used as an input for the bubble-tracking model. In the bubble-tracking model, vapour is distributed in the liquid in the form of individually tracked bubbles. The result of the Lagrangian simulation is a non-homogeneous distribution of local Sauter diameter, which is used in the two-fluid model to predict the interfacial forces and interfacial transfer rates of mass and heat transfer. The coupled approach requires a few iterations to obtain a converged solution. The results of the proposed approach were validated against boiling flow experiments from the literature. A good agreement between measured and calculated radial profiles of void fraction and bubble diameter was obtained.

Simulation of Subcooled Nucleate Boiling in a Vertical Annulus With Coupling of Bubble-Tracking and Two-Fluid Models: Further Comparison With Experimental Results

2006 ◽  
Author(s):  
Ivo Kljenak ◽  
Bosˇtjan Koncˇar ◽  
Borut Mavko
Keyword(s):  
Fluid Model ◽  
Three Dimensional ◽  
Vertical Channel ◽  
Nucleate Boiling ◽  
Bubble Nucleation ◽  
Experimental Results ◽  
Tracking Model ◽  
Two Fluid Model ◽  
Vertical Annulus ◽  
Two Fluid

A model of subcooled nucleate boiling flow in a vertical channel at low pressure conditions that was developed earlier is further validated by comparison of simulations with experimental results from Purdue University (USA). The model consists of a three-dimensional bubble-tracking model and a two-dimensional two-fluid model which are coupled off-line. By taking into account dynamic phenomena (liquid flow, bubble motion and interaction) and thermal phenomena (liquid heating, bubble nucleation and condensation), the model is able to simulate the gradual evolution of void fraction profiles along the boiling channel.

A Linear Time-Domain Two-Fluid Model Analysis of Dynamic Instability in Boiling Flow Systems

1986 ◽  
Vol 108 (1) ◽  
pp. 100-108 ◽  
Author(s):  
R. C. Dykhuizen ◽  
R. P. Roy ◽  
S. P. Kalra
Keyword(s):  
Time Domain ◽  
Dynamic Instability ◽  
Linear Time ◽  
Fluid Model ◽  
Density Wave ◽  
Model Description ◽  
Flow Systems ◽  
Boiling Flow ◽  
Two Fluid Model ◽  
Two Fluid

A linear analysis of dynamic instability in boiling flow systems has been carried out in the time domain. An unequal velocity, unequal temperature two-fluid model description of boiling flow is used. Instability threshold results of the density-wave oscillation type obtained have been compared with experimental data from Refrigerant-113 and water systems with satisfactory agreement.

Prediction of Parameters Distribution of Upward Boiling Two-Phase Flow With Two-Fluid Models

2002 ◽  
Author(s):  
Wei Yao ◽  
Christophe Morel
Keyword(s):  
Void Fraction ◽  
Fluid Model ◽  
Constitutive Relations ◽  
Turbulent Dispersion ◽  
Dispersion Force ◽  
Liquid Temperature ◽  
Two Phase ◽  
Radial Profiles ◽  
Two Fluid Model ◽  
Two Fluid

In this paper, a multidimensional two-fluid model with additional turbulence k–ε equations is used to predict the two-phase parameters distribution in freon R12 boiling flow. The 3D module of the CATHARE code is used for numerical calculation. The DEBORA experiment has been chosen to evaluate our models. The radial profiles of the outlet parameters were measured by means of an optical probe. The comparison of the radial profiles of void fraction, liquid temperature, gas velocity and volumetric interfacial area at the end of the heated section shows that the multidimensional two-fluid model with proper constitutive relations can yield reasonably predicted results in boiling conditions. Sensitivity tests show that the turbulent dispersion force, which involves the void fraction gradient, plays an important role in determining the void fraction distribution; and the turbulence eddy viscosity is a significant factor to influence the liquid temperature distribution.

A two-fluid model simulation of an industrial moving grate waste incinerator

2020 ◽  
Vol 104 ◽  
pp. 183-191 ◽  
Author(s):  
Zihong Xia ◽  
Peng Shan ◽  
Caixia Chen ◽  
Hailiang Du ◽  
Jie Huang ◽  
...  
Keyword(s):  
Model Simulation ◽  
Fluid Model ◽  
Waste Incinerator ◽  
Two Fluid Model ◽  
Two Fluid
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