The space–time CE/SE method for solving single and two-phase shallow flow models

2014 ◽  
Vol 96 ◽  
pp. 136-151 ◽  
Author(s):  
Shamsul Qamar ◽  
Saqib Zia ◽  
Waqas Ashraf
Keyword(s):  
Space Time ◽  
Shallow Flow ◽  
Two Phase ◽  
Flow Models

scholarly journals Port-Hamiltonian formulation of two-phase flow models

2021 ◽  
Vol 149 ◽  
pp. 104881
Author(s):  
H. Bansal ◽  
P. Schulze ◽  
M.H. Abbasi ◽  
H. Zwart ◽  
L. Iapichino ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Hamiltonian Formulation ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Models

scholarly journals Measurements of pitch-off diameter of gas bubbles in liquid metal

2021 ◽  
Vol 2057 (1) ◽  
pp. 012039
Author(s):  
P D Lobanov ◽  
N A Pribaturin ◽  
A I Svetonosov
Keyword(s):  
Liquid Metal ◽  
High Speed ◽  
Electrical Circuit ◽  
Conductivity Method ◽  
Two Phase ◽  
Flow Models ◽  
Bubble Detachment ◽  
Transparent Liquid ◽  
Outflow Channel ◽  
The Rose

Abstract To determine the separation diameter of bubbles in a liquid metal melt, an original technique based on the conductivity method is proposed. A thin electrode is installed in the center of the outflow channel, and the separation of bubbles is determined by closing and opening the electrical circuit. In this way, the separation frequency of the bubbles and their volume can be determined. Additional studies are carried out on a transparent liquid (water). It is shown that the presence of an electrode has little effect on the process of bubble detachment. The processing data of high-speed video filming and the proposed method in a transparent liquid coincide with high accuracy. Measurements of the frequency of bubble detachment in melts of the Rose and lead alloy are carried out. The results obtained are used to tune two-phase flow models when simulating fast neutron reactors with heavy liquid metal coolants.

Homogeneous two-phase flow models and accurate steam-water table look-up method for fast transient simulations

2017 ◽  
Vol 95 ◽  
pp. 199-219 ◽  
Author(s):  
M. De Lorenzo ◽  
Ph. Lafon ◽  
M. Di Matteo ◽  
M. Pelanti ◽  
J.-M. Seynhaeve ◽  
...  
Keyword(s):  
Water Table ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Models ◽  
Transient Simulations ◽  
Fast Transient

scholarly journals Validation of the generalized model of two-phase thermosyphon loop based on experimental measurements of volumetric flow rate

2016 ◽  
Vol 37 (3) ◽  
pp. 109-138 ◽  
Author(s):  
Henryk Bieliński
Keyword(s):  
Steady State ◽  
Flow Rate ◽  
Vertical Section ◽  
Volumetric Flow Rate ◽  
Working Fluid ◽  
Two Phase ◽  
Generalized Model ◽  
Flow Models ◽  
Theoretical Predictions ◽  
The One

AbstractThe current paper presents the experimental validation of the generalized model of the two-phase thermosyphon loop. The generalized model is based on mass, momentum, and energy balances in the evaporators, rising tube, condensers and the falling tube. The theoretical analysis and the experimental data have been obtained for a new designed variant. The variant refers to a thermosyphon loop with both minichannels and conventional tubes. The thermosyphon loop consists of an evaporator on the lower vertical section and a condenser on the upper vertical section. The one-dimensional homogeneous and separated two-phase flow models were used in calculations. The latest minichannel heat transfer correlations available in literature were applied. A numerical analysis of the volumetric flow rate in the steady-state has been done. The experiment was conducted on a specially designed test apparatus. Ultrapure water was used as a working fluid. The results show that the theoretical predictions are in good agreement with the measured volumetric flow rate at steady-state.

Steady one-dimensional nozzle flow solutions of liquid–gas mixtures

2013 ◽  
Vol 737 ◽  
pp. 146-175 ◽  
Author(s):  
S. LeMartelot ◽  
R. Saurel ◽  
O. Le Métayer
Keyword(s):  
Two Phase Flow ◽  
Gas Mixtures ◽  
Ideal Gas ◽  
Nozzle Flow ◽  
Pure Liquid ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Flow Models ◽  
Relaxation Effects

AbstractExact compressible one-dimensional nozzle flow solutions at steady state are determined in various limit situations of two-phase liquid–gas mixtures. First, the exact solution for a pure liquid nozzle flow is determined in the context of fluids governed by the compressible Euler equations and the ‘stiffened gas’ equation of state. It is an extension of the well-known ideal-gas steady nozzle flow solution. Various two-phase flow models are then addressed, all corresponding to limit situations of partial equilibrium among the phases. The first limit situation corresponds to the two-phase flow model of Kapila et al. (Phys. Fluids, vol. 13, 2001, pp. 3002–3024), where both phases evolve in mechanical equilibrium only. This model contains two entropies, two temperatures and non-conventional shock relations. The second one corresponds to a two-phase model where the phases evolve in both mechanical and thermal equilibrium. The last one corresponds to a model describing a liquid–vapour mixture in thermodynamic equilibrium. They all correspond to two-phase mixtures where the various relaxation effects are either stiff or absent. In all instances, the various flow regimes (subsonic, subsonic–supersonic, and supersonic with shock) are unambiguously determined, as well as various nozzle solution profiles.

scholarly journals Numerical Model for Cavitational Flow in Hydraulic Poppet Valves

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Sandor I. Bernad ◽  
Romeo Susan-Resiga
Keyword(s):  
Liquid Flow ◽  
Bubble Dynamics ◽  
Flow Analysis ◽  
Cavitating Flow ◽  
Absolute Pressure ◽  
Two Phase ◽  
Current Effort ◽  
Flow Models ◽  
Density Distributions ◽  
Phase Liquid

The paper presents a numerical simulation and analysis of the flow inside a poppet valve. First, the single-phase (liquid) flow is investigated, and an original model is introduced for quantitatively describing the vortex flow. Since an atmospheric outlet pressure produces large negative absolute pressure regions, a two-phase (cavitating) flow analysis is also performed. Both pressure and density distributions inside the cavity are presented, and a comparison with the liquid flow results is performed. It is found that if one defines the cavity radius such that up to this radius the pressure is no larger than the vaporization pressure, then both liquid and cavitating flow models predict the cavity extent. The current effort is based on the application of the recently developed full cavitation model that utilizes the modified Rayleigh-Plesset equations for bubble dynamics.

Automated Subsea Architecture Optimization Using Low-Dimensional Multiphase Flow Models

2019 ◽  
Author(s):  
Zurwa Khan ◽  
Amine Meziou ◽  
Reza Tafreshi ◽  
Matthew Franchek ◽  
Karolos Grigoriadis
Keyword(s):  
Multiphase Flow ◽  
Thermal Model ◽  
Effective Control ◽  
Two Phase ◽  
Validation Data ◽  
Flow Models ◽  
Dimensional Models ◽  
Low Dimensional ◽  
Architecture Optimization

Abstract Due to the global increase in energy demand, the need for economic oil and gas production is rising more than ever. Therefore, it is necessary to ensure that subsea architecture designs are economical and safety oriented. While numerous challenges are encountered during subsea system’s installation and operation phases, most of these challenges can be avoided by ensuring an economical and reliable design. For a safe and cost-effective design and operating scenario, it is essential to predict the hydraulic and thermal behavior of multiphase fluid encountered in petroleum pipelines for a range of conditions. This cannot be accomplished by empirical models, which are dependent on limited data available. Consequently, mechanistic low-dimensional models have been used for two-phase gas-liquid steady-state flow. However, mechanistic low-dimensional models assume adiabatic conditions, which is rarely the case in subsea architectures, which encounter cold surroundings. Therefore, to predict the temperature-based characteristics of multiphase flow in environments with thermal gradients, a thermal model has been developed and validated with experimental data. 80% of the validation data was predicted by this developed thermal model with error difference of less than 30%. The developed two-phase gasliquid thermal model was merged with Beggs and Brill hydraulic multiphase flow model to predict the overall behavior of two-phase gas-liquid flow, and used to develop an optimal model-based multi-well subsea architecture design. A case study of a four-well subsea system was used to demonstrate the automated subsea architecture optimization technique. Through this case study, it was shown that approximately 23% of savings in pipelines procurement could be made relative to the conventional designing approach. Industry standards, safety factors, and multiphase flow models were used to design jumpers and place the manifold for a subsea multi-well system. Merging hydraulic and thermal multiphase flow models showed the effect of temperature on the flow, which led to an optimized design for the subsea insulation in which issues such as wax deposition can be prevented. The resulting optimized subsea architecture was then implemented in Simscape® environment to obtain the transient response. Along with optimized subsea architecture automated design, the developed thermal model has the potential to be used for real-time prediction of two-phase flow rate, pressure drop and void fraction as virtual sensors to provide economical alternative to expensive and impractical hardware sensors. Furthermore, the developed model can also be used to design effective control strategies for multiphase flow regulation in jumpers and prevention of backflow at the manifold.

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