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.

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 ACC Configuration Sensitivity Study for AP1000 Large Break LOCA

2013 ◽  
Author(s):  
Jianhui Yu
Keyword(s):  
Nuclear Power ◽  
Initial Conditions ◽  
Heat Removal ◽  
Initial Pressure ◽  
Sensitivity Study ◽  
Water Volume ◽  
Initial Water ◽  
The Core ◽  
Coolant System ◽  
Residual Heat

Similar to the traditional nuclear power plant (NPP), the Accumulator (ACC) of AP1000 is one of the most important facility against Large-Break LOCA (LBLOCA). Following a LBLOCA, the Reactor Coolant System (RCS) pressure will be decreased rapidly. And the Core Makeup Tank (CMT) and Passive Residual Heat Removal (PRHR) will be actuated following “S” signal. However, the transient is so rapid that the CMT and PRHR could not be actuated timely, because the ACC will inject water into the reactor vessel downcomer through Direct Vessel Injection (DVI) line and it will stop the CMT injection immediately when RCS has depressurized to the ACC pressure. Therefore, the ACC configuration is very important to LBLOCA mitigation for AP1000. And the Peak Cladding Temperature (PCT) highly relies on ACC configuration. Several sets of different configuration of both ACC, including initial pressure and initial water volume, are discussed. Different initial conditions (e.g. ACC initial pressure) are considered in the sensitivity study on ACC depressurization phase by phase. WCOBRA/TRAC code was used to perform the LBLOCA sensitivity study. The results of each sensitivity case are presented and analyzed. And the suggestion of how to make the optimal ACC configuration is provided in this paper.

Hydrodynamic Study of a Water-Propelled Rocket: An Undergraduate Experiment in Fluid Mechanics

2005 ◽  
Author(s):  
Glen E. Thorncroft ◽  
Christopher C. Pascual
Keyword(s):  
Test Data ◽  
Pedagogical Approach ◽  
Two Phase ◽  
Experimental Conditions ◽  
Initial Water ◽  
Pressurized Water ◽  
A Value ◽  
Hydrodynamic Study ◽  
Best Fit ◽  
Polytropic Exponent

An undergraduate experiment has been developed to measure the performance of a pressurized water rocket and compare test data to an analytical model developed from fluid momentum. A rocket and test stand were developed to measure the net thrust of the rocket, as well the air pressure and temperature inside the rocket, as a function of time. The model compares well to test data from four conditions, combinations of two initial water heights and two initial air pressures. The air in the rocket was assumed to under go polytropic expansion, and a value of 1.1 for the polytropic exponent was found to best fit the model to all experimental conditions. Experimental observations also reveal that, at higher air pressures, the air mixes with the expelled water, resulting in a two-phase flow that reduces the net thrust of the rocket. A pedagogical approach is also developed for the experiment and is described indetail.

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.

Investigation of axisymmetric wave flows under interaction of a spherical impact pulse with a barrier of aqueous foam

2017 ◽  
Vol 12 (2) ◽  
pp. 238-243 ◽  
Author(s):  
R.Kh. Bolotnova ◽  
E.F. Gainullina
Keyword(s):  
Computer Modeling ◽  
Volume Content ◽  
Liquid Mixture ◽  
Numerical Implementation ◽  
Two Dimensional ◽  
Foam Layer ◽  
Two Phase ◽  
Impact Pulse ◽  
Aqueous Foam ◽  
Spherical Explosion

The problem of spherical explosion in the gas region with a protective foam layer is solved in a two-dimensional axisymmetric formulation using a two-phase model of a gas-liquid mixture that includes the laws of conservation of mass, momentum and energy of the mixture and the equation for the dynamics of the volume content of phases. The numerical implementation of the model was carried out by modifying the standard solver of the compressibleMultiphaseInterFoam of the open package OpenFOAM. The results of computer modeling are visualized using the ParaView graphical platform.

Numerical Modeling of Evolution of Boundary Between Incompressible Gas and Liquid in Two-Dimensional Region

2006 ◽  
Vol 4 ◽  
pp. 224-236
Author(s):  
A.S. Topolnikov
Keyword(s):  
Numerical Modeling ◽  
Interphase Boundary ◽  
Incompressible Liquid ◽  
Stokes Equations ◽  
Numerical Code ◽  
Navier Stokes ◽  
Two Phase ◽  
Navier Stokes Equations ◽  
Incompressible Media ◽  
Good Agreement

The paper is devoted to numerical modeling of Navier–Stokes equations for incompressible media in the case, when there exist gas and liquid inside the rectangular calculation region, which are separated by interphase boundary. The set of equations for incompressible liquid accounting for viscous, gravitational and surface (capillary) forces is solved by finite-difference scheme on the spaced grid, for description of interphase boundary the ideology of Level Set Method is used. By developed numerical code the set of hydrodynamic problems is solved, which describe the motion of two-phase incompressible media with interphase boundary. As a result of numerical simulation the solutions are obtained, which are in good agreement with existing analytical and experimental solutions.

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.

Sign in / Sign up

Export Citation Format

Share Document