Influence of aqueous foam syneresis on the shock wave propagation velocity

2020 ◽  
Vol 15 (3-4) ◽  
pp. 159-166
Author(s):  
E.F. Gainullina
Keyword(s):  
Experimental Data ◽  
Shock Wave ◽  
Numerical Solutions ◽  
Liquid Fraction ◽  
Pulse Velocity ◽  
Shock Pulse ◽  
Contact Heat ◽  
Two Phase ◽  
Aqueous Foam ◽  
Droplet Mixture

Numerical simulation of the spherical shock pulse propagation in aqueous foam with volumetric liquid fraction of 0.0083 has been carried out in accordance with the published experimental data on the explosion of HE in aqueous foam. The assumption is used that the foam structure is destroyed by the shock wave, which leads to the transformation of the foam into a monodisperse gas-droplet mixture. The system of equations for the two-phase gas-droplet model of aqueous foam includes the laws of conservation of mass, momentum, energy for each phase and the equation for the dynamics of the volumetric liquid fraction in a single-pressure, two-velocity, two-temperature approximations in a three-dimensional formulation and takes into account the forces of the Schiller-Naumann interfacial drag, the Ranz-Marshall interphase contact heat exchange and the effect of foam syneresis on the initial distribution of its volumetric liquid fraction. Realistic equations of state in the form of Peng-Robinson and Mie-Gruneisen are used to describe the thermodynamic properties of air and water that make up a gas-droplet mixture. Numerical modeling of the processes under consideration was carried out in the open software of computational fluid dynamics OpenFOAM using the finite volume method based on the iterative two-step PIMPLE algorithm. The analysis of the effect of foam syneresis on the dynamics of shock pulse in aqueous foam is given. It was found that the uneven distribution of the liquid fraction in the foam, caused by its sedimentation under the gravity, leads to the increase in the shock pulse velocity in upper layers of the foam. In comparative analysis of numerical solutions and experimental data at sensor locations, the importance of taking into account syneresis phenomena in modeling the dynamics of shock wave in aqueous foam is shown. The reliability of calculations obtained by the proposed model is confirmed by their agreement with experimental data.

Modeling of the spherical explosion attenuation process using aqueous foam

2019 ◽  
Vol 14 (2) ◽  
pp. 108-114
Author(s):  
R.Kh. Bolotnova ◽  
E.F. Gainullina ◽  
E.A. Nurislamova
Keyword(s):  
Shock Wave ◽  
Numerical Solution ◽  
Volume Fraction ◽  
Strong Shock ◽  
Liquid Volume ◽  
Contact Heat ◽  
Liquid Volume Fraction ◽  
Aqueous Foam ◽  
Spherical Explosion ◽  
Droplet Mixture

The two-phase model of dry aqueous foam dynamic behavior under the strong shock wave influence is presented under assumption that the foam structure under shock loading is destroyed into a suspension of monodispersed microdrops with the formation of a gas-droplet mixture. The system of equations for the model of aqueous foam includes the laws of conservation of mass, momentum and energy for each phase in accordance with the single-pressure, two-speed, two-temperature approximations in a three-dimensional formulation, taking into account the Schiller–Naumann interfacial drag force and the Ranz–Marshall interfacial contact heat transfer. The thermodynamic properties of air and water forming a gas-droplet mixture are described by the Peng–Robinson and Mie–Grueneisen equations of state. The presence of non-uniform process in height of aqueous foam syneresis, which is due to gravitational forces, is taken into account by setting the distribution of the liquid volume fraction in the foam. An additional consideration of the syneresis process during calculating the intensity of interphase drag forces according to the Schiller–Naumann model was controlled by introducing the parameter depending on the spatial distribution of the initial liquid volume fraction of the foam. The spherical explosion is modeled in the form of the shock wave pulse whose energy coincided with the charge energy of the HE used in the experiments. The problem numerical solution is implemented using the OpenFOAM free software package based on the two-step PIMPLE computational algorithm. The numerical solution of the problem, obtained on the basis of the proposed gas-droplet mixture model, is in satisfactory agreement with the experimental data on a spherical explosion in aqueous foam. The analysis of the spherical shock wave dynamics while its propagation through aqueous foam is given. The causes of the significant decrease in the amplitude and velocity shock waves propagation in the medium under study are investigated.

The Numerical Modeling of Spherical Explosion in the Foam

2016 ◽  
Vol 11 (1) ◽  
pp. 60-65 ◽  
Author(s):  
R.Kh. Bolotnova ◽  
E.F. Gainullina
Keyword(s):  
Shock Wave ◽  
Numerical Modeling ◽  
Initial Pressure ◽  
Water Volume ◽  
Symmetric Model ◽  
Two Phase ◽  
Experimental Conditions ◽  
Initial Water ◽  
Aqueous Foam ◽  
Spherical Explosion

The spherical explosion propagation process in aqueous foam with the initial water volume content α10=0.0083 corresponding to the experimental conditions is analyzed numerically. The solution method is based on the one-dimensional two-temperature spherically symmetric model for two-phase gas-liquid mixture. The numerical simulation is built by the shock capturing method and movable Lagrangian grids. The amplitude and the width of the initial pressure pulse are found from the amount of experimental explosive energy. The numerical modeling results are compared to the real experiment. It’s shown, that the foam compression in the shock wave leads to the significant decrease in velocity and in amplitude of the shock wave.

Study of Foam Flow in a Gas-Liquid Cylindrical Cyclone (GLCC) Compact Separator

2009 ◽  
Author(s):  
No´lides M. Guzma´n ◽  
Ovadia Shoham ◽  
Ram Mohan
Keyword(s):  
Experimental Data ◽  
Flow Behavior ◽  
Two Phase ◽  
Operational Conditions ◽  
Foam Flow ◽  
Aqueous Foam ◽  
Flow Characterization ◽  
Cylindrical Cyclone ◽  
Static Trap ◽  
Break Up

Aqueous foam flow behavior in a Gas-Liquid Cylindrical Cyclone (GLCC) is studied experimentally and theoretically with the objective of determine the operational envelop for foam break up. An existing experimental two-phase facility was modified to enable foam flow characterization. Several experimental data were acquired for aqueous foam using a compact inlet cyclone. These include: foam characterization in static trap sections, and foam flow behavior in the cyclone. Saint-Jalmes et al. (2000) model has been modified for characterization of foam evolution in static trap sections including the prediction of the drainage interface height with time. In addition, a new model for the prediction of the operational envelop for foam break up in the cyclone based on foam characteristics was developed. Good agreement is observed between the experimental data and the predictions of the models. It can be concluded that depending on the operational conditions the GLCC can act either as a foam breaker or as a foam generator. The developed model for the prediction of the operational envelop for foam break up separates these two modes of operations of the GLCC.

scholarly journals Modeling of weak shock waves propagation in aqueous foam layer

2021 ◽  
Vol 2103 (1) ◽  
pp. 012217
Author(s):  
R Kh Bolotnova ◽  
E F Gainullina
Keyword(s):  
Shock Waves ◽  
Equations Of State ◽  
Weak Shock ◽  
Foam Layer ◽  
Contact Heat ◽  
Two Phase ◽  
Aqueous Foam ◽  
Proposed Model ◽  
Waves Propagation ◽  
Two Temperature

Abstract Dynamics of low-intensity air shock waves in the shock tube containing an aqueous foam layer is theoretically investigated. Modeling of studied process is carried out using two-phase model of aqueous foam developed by the authors in single-pressure, single-speed and two-temperature approximations. The model takes into account the Ranz-Marshall interphase contact heat transfer, effective Herschel-Bulkley viscosity, which describes foam behavior as a non-Newtonian fluid, and elastic properties of aqueous foam under a weak shock impaction without destruction of foam structure. Properties of air and water as the foam components are described by realistic equations of state. Computer implementation of the aqueous foam model is carried out in the solver, developed by the authors in OpenFOAM software. The influence of aqueous foam viscoelastic properties on the intensity and structure of a shock wave has been investigated. When analyzing the obtained solutions, reliability of the proposed model and method of numerical modeling is estimated by comparative analysis of the found solutions and literature experimental data.

Bounds on Two-Phase Flow: Part II — Void Fraction in Circular Pipes

2005 ◽  
Author(s):  
M. M. Awad ◽  
Y. S. Muzychka
Keyword(s):  
Experimental Data ◽  
Void Fraction ◽  
Mass Flow ◽  
Liquid Fraction ◽  
Published Data ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Working Fluids ◽  
Mass Flow Rates

Theoretical and empirical models for the gas void fraction (α) are reviewed. Simple rules are developed for obtaining rational bounds for the void fraction in two-phase flow. The lower bound is based on the separate cylinders formulation for turbulent-turbulent flow that uses the Blasius equation to predict the Fanning friction factor. The upper bound is based on the Butterworth relationship that represents well the Lockhart-Martinelli correlation. These two bounds are reversed in the case of liquid fraction (1−α). The bounds models are verified using published experimental data of void fraction versus mass quality at constant mass flow rate. The published data include different working fluids such as R-12 and R-22 at different pipe diameters, different pressures, and different mass flow rates. It is shown that the published data can be well bounded for a wide range of mass qualities, pipe diameters, pressures and mass flow rates. Further comparisons are made using the published experimental data of void fraction (α) and liquid fraction (1−α) versus the Lockhart-Martinelli parameter (X), for different working fluids such as R-12, R-22 and air-water mixtures.

Features of propagation of shock waves in aqueous foams with an inhomogeneous density

2012 ◽  
Vol 9 (1) ◽  
pp. 41-46
Author(s):  
R.Kh. Bolotnova ◽  
U.O. Agisheva
Keyword(s):  
Experimental Data ◽  
Shock Wave ◽  
Wave Interaction ◽  
Damping Properties ◽  
Numerical Investigations ◽  
Shock Wave Interaction ◽  
Aqueous Foam ◽  
Aqueous Foams ◽  
Inhomogeneous Density ◽  
Comparison With Experimental Data

Numerical investigations and comparison with experimental data of the shock wave interaction with aqueous foam barrier are conducted, taking into account the change of the foamy veil density on time. The efficiency of damping properties of foam barriers depends on water content is evaluated.

Features of spatial shock-wave flows in vapor-gas-liquid mixtures

2014 ◽  
Vol 10 ◽  
pp. 27-31
Author(s):  
R.Kh. Bolotnova ◽  
U.O. Agisheva ◽  
V.A. Buzina
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Shock Waves ◽  
Liquid Mixture ◽  
Liquid Mixtures ◽  
Pressure Vessels ◽  
Water Mixture ◽  
Two Dimensional ◽  
Nonstationary Processes ◽  
Two Phase

The two-phase model of vapor-gas-liquid medium in axisymmetric two-dimensional formulation, taking into account vaporization is constructed. The nonstationary processes of boiling vapor-water mixture outflow from high-pressure vessels as a result of depressurization are studied. The problems of shock waves action on filled by gas-liquid mixture volumes are solved.

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