scholarly journals The use of the inverse problem methodology in analysis of fluid flow through granular beds with non-uniform grain sizes

2021 ◽  
Author(s):  
Wojciech Sobieski ◽  
Anna Trykozko
Keyword(s):  
Experimental Data ◽  
Inverse Problem ◽  
Numerical Models ◽  
The Finite Element Method ◽  
Optimal Method ◽  
Gravel Beds ◽  
Grain Sizes ◽  
Wide Range ◽  
Large Particles ◽  
Flow Through

The pressure drop during water flow through two gravel beds with 2-8 and 8-16 [mm] grain size was measured across a wide range of filtration velocities, and the optimal method for calculating the coefficients for Darcy’s law and Forchheimer’s law was selected. The laws and the experimental data were used to develop a computational program based on the Finite Element Method (FEM). The results were compared, and errors were analyzed to determine which law better describes flow data. Various methods of measuring porosity and average grain diameter, representative of the sample, were analyzed. The data were used to determine the limits of applicability of both laws. The study was motivated by the observation that computational formulas in the literature produce results that differ by several orders of magnitude, which significantly compromises their applicability. The present study is a continuation of our previous research into artificial granular materials with similarly sized particles. In our previous work, the results produced by analytical and numerical models were highly consistent with the experimental data. The aim of this study was to determine whether the inverse problem methodology can deliver equally reliable results in natural materials composed of large particles. The experimental data were presented in detail to facilitate the replication, reproduction and verification of all analyses and calculations.

scholarly journals Combined numerical and experimental study of microstructure and permeability in porous granular media

2020 ◽  
Author(s):  
Philipp Eichheimer ◽  
Marcel Thielmann ◽  
Wakana Fujita ◽  
Gregor J. Golabek ◽  
Michihiko Nakamura ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Numerical Simulations ◽  
Granular Media ◽  
Large Scale ◽  
Earth Science ◽  
Numerical Models ◽  
Effective Porosity ◽  
Flow Properties ◽  
Wide Range ◽  
Flow Through

Abstract. Fluid flow on different scales is of interest for several Earth science disciplines like petrophysics, hydrogeology and volcanology. To parameterize fluid flow in large-scale numerical simulations (e.g. groundwater and volcanic systems), flow properties on the microscale need to be considered. For this purpose experimental and numerical investigations of flow through porous media over a wide range of porosities are necessary. In the present study we sinter glass bead media with various porosities. The microstructure, namely effective porosity and effective specific surface, is investigated using image processing. We determine flow properties like hydraulic tortuosity and permeability using both experimental measurements and numerical simulations. By fitting microstructural and flow properties to porosity, we obtain a modified Kozeny-Carman equation for isotropic low-porosity media, that can be used to simulate permeability in large-scale numerical models. To verify the modified Kozeny-Carman equation we compare it to the computed and measured permeability values.

Interpretation of Mechanical Testing Measurements for Pastes

2002 ◽  
Author(s):  
Robert A. Basterfield ◽  
Chris J. Lawrence ◽  
Michael J. Adams
Keyword(s):  
Experimental Data ◽  
Numerical Models ◽  
Experimental Methods ◽  
Published Data ◽  
The Finite Element Method ◽  
Material Parameters ◽  
Simulation Techniques ◽  
Manufacturing Sectors ◽  
Product Forms ◽  
Computer Simulation Techniques

Pastes occur as intermediates or final product forms in many industrially important manufacturing sectors. The use of computer simulation techniques, such as the finite element method, is becoming more common in the design of paste processing operations. A major problem in the application of this approach is the development of sufficiently representative materials models. It has been established that pastes may be described as elasto-viscoplastic materials with the plastic flow being governed by the Herschel-Bulkley relationship. This paper describes the development of analytical and numerical models that can be used as a basis for deriving the material parameters from experimental data obtained using extrusion, compression and bending procedures. Measurements have also been carried out on a model paste and the derived material parameters are compared with published data for the same paste. The merits of the three experimental methods are compared on this basis.

Stresses in Thick Pressure Vessel Heads

1990 ◽  
Vol 112 (1) ◽  
pp. 108-114
Author(s):  
A. V. Singh ◽  
V. Kumar
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Finite Element ◽  
Pressure Vessel ◽  
The Finite Element Method ◽  
Solid Of Revolution ◽  
Wide Range ◽  
Radial Thrust ◽  
Thrust Load ◽  
Spherical Pressure

The finite element method is used to study stresses in two types of spherical pressure vessel heads having very wide range of applications in industries. The first problem involves a nozzle to sphere intersection reinforced by a pad and subjected to radial thrust load. The second problem deals with a pressurized thick hemispherical drumhead with a circular manhole. These structures are modeled using eight-node axisymmetric solid of revolution finite elements. Numerical values of circumferential and meridional stresses from the present analysis show excellent agreement with experimental data from the literature.

Analysis of Heat Transfer and Fluid Flow Through a Spirally Fluted Tube Using a Porous Substrate Approach

1994 ◽  
Vol 116 (3) ◽  
pp. 543-551 ◽  
Author(s):  
Vijayaragham Srinivasan ◽  
Kambiz Vafai ◽  
Richard N. Christensen
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Porous Substrate ◽  
The Finite Element Method ◽  
Nusselt Numbers ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Friction Factors ◽  
Flow Through ◽  
Good Agreement

An innovative approach was opted for modeling the flow and heat transfer through spirally fluted tubes. The model divided the flow domain into two regions. The flutes were modeled as a porous substrate with direction-dependent permeabilities. This enabled modeling the swirl component in the fluted tube. The properties of the porous substrate such as its thickness, porosity, and ratio of the direction-dependent permeabilities were obtained from the geometry of the fluted tube. Experimental data on laminar Nusselt numbers and friction factors for different types of fluted tubes representing a broad range of flute geometry were available. Experimental data from a few of the tubes tested were used to propose a relationship between the permeability of the porous substrate and the flute parameters, particularly the flute spacing. The governing equations were discretized using the Finite Element Method. The model was verified and applied to the other tubes in the test matrix. Very good agreement was found between the numerical predictions and the experimental data.

scholarly journals Review and a Theoretical Approach on Pressure Drop Correlations of Flow through Open-Cell Metal Foam

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3153
Author(s):  
Huizhu Yang ◽  
Yongyao Li ◽  
Binjian Ma ◽  
Yonggang Zhu
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Metal Foam ◽  
Flow Characteristics ◽  
Metal Foams ◽  
High Porosity ◽  
Open Cell ◽  
Wide Range ◽  
Flow Through

Due to their high porosity, high stiffness, light weight, large surface area-to-volume ratio, and excellent thermal properties, open-cell metal foams have been applied in a wide range of sectors and industries, including the energy, transportation, aviation, biomedical, and defense industries. Understanding the flow characteristics and pressure drop of the fluid flow in open-cell metal foams is critical for applying such materials in these scenarios. However, the state-of-the-art pressure drop correlations for open-cell foams show large deviations from experimental data. In this paper, the fundamental governing equations of fluid flow through open-cell metal foams and the determination of different foam geometry structures are first presented. A variety of published models for predicting the pressure drop through open-cell metal foams are then summarized and validated against experimental data. Finally, two empirical correlations of permeability are developed and recommended based on the model of Calmidi. Moreover, Calmidi’s model is proposed to calculate the Forchheimer coefficient. These three equations together allow calculating the pressure drop through open-cell metal foam as a function of porosity and pore diameter (or strut diameter) in a wide range of porosities ε = 85.7–97.8% and pore densities of 10–100 PPI. The findings of this study greatly advance our understanding of the flow characteristics through open-cell metal foam and provide important guidance for the design of open-cell metal foam materials for different engineering applications.

scholarly journals Numerical Optimisation of Blowing Glass Parison Shapes

2009 ◽  
Author(s):  
J. A. W. M. Groot ◽  
C. G. Giannopapa ◽  
R. M. M. Mattheij
Keyword(s):  
Inverse Problem ◽  
Level Set ◽  
Numerical Models ◽  
Level Set Methods ◽  
Analytical Approximation ◽  
Initial Guess ◽  
Glass Containers ◽  
Wide Range ◽  
Container Shape ◽  
Air Interfaces

Industrial glass blowing is an essential stage of manufacturing glass containers, i.e. bottles or jars. An initial glass preform is brought into a mould and subsequently blown into the mould shape. Over the last few decades, a wide range of numerical models for forward glass blow process simulation have been developed. A considerable challenge is the inverse problem: to determine an optimal preform from the desired container shape. A simulation model for blowing glass containers based on finite element methods has previously been developed [1, 2]. This model uses level set methods to track the glass-air interfaces. In previous work of the authors [3] a numerical method was introduced for optimising the shape of the preform. The optimisation method aims at minimising the error in the level set representing the inner container surface. The objective of this paper is to analyse the inverse problem by means of an analytical approximation of the flow problem and to improve the performance of the optimisation method previously introduced. In particular an initial guess of the preform for the iterative optimisation algorithm is constructed from the approximate solution of the inverse problem. The main goals of this work are the analysis of the inverse problem and the development of the optimisation method in consideration of the application to containers of industrial relevance.

scholarly journals Experimental Data of a Floating Cylinder in a Wave Tank: Comparison Solid and Water Ballast

Data ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 146 ◽  
Author(s):  
Roman Gabl ◽  
Thomas Davey ◽  
Edd Nixon ◽  
Jeffrey Steynor ◽  
David M. Ingram
Keyword(s):  
Experimental Data ◽  
Numerical Models ◽  
Water Volume ◽  
Initial Amplitude ◽  
Regular Waves ◽  
Floating Structure ◽  
Wave Tank ◽  
Wide Range ◽  
Set Up ◽  
Fluid Interaction

The experimental set-up allows for the comparison of two different ballast options of a floating cylinder in a wave tank. Four different internal water drafts are tested as well as an equivalent solid ballast option. The model is excited by regular waves, which are characterised with five wave gauges in front of the floating cylinder and two behind. Additionally, the time series of the six-degree freedom response of the floating structure is made available. Regular waves with an initial amplitude of 0.05 m and frequencies over the range 0.3 to 1.1 Hz are investigated. This results in a wide range of different responses of the floating structure as well as very big rotations of up to 20 degrees. This dataset allows for identification of the influence caused by the sloshing of the interior water volume and can be used to validate numerical models of fluid–structure–fluid interaction.

scholarly journals Combined numerical and experimental study of microstructure and permeability in porous granular media

2020 ◽  
Author(s):  
Philipp Eichheimer ◽  
Marcel Thielmann ◽  
Wakana Fujita ◽  
Gregor J. Golabek ◽  
Michihiko Nakamura ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Numerical Simulations ◽  
Granular Media ◽  
Large Scale ◽  
Earth Science ◽  
Numerical Models ◽  
Effective Porosity ◽  
Flow Properties ◽  
Wide Range ◽  
Flow Through

<div> <div> <div> <p>Fluid flow on different scales is of interest for several Earth science disciplines like petrophysics, hydrogeology and volcanology. To parameterize fluid flow in large-scale numerical simulations (e.g. groundwater and volcanic systems), flow properties on the microscale need to be considered. For this purpose experimental and numerical investigations of flow through porous media over a wide range of porosities are necessary. In the present study we sinter glass bead media with various porosities, representing shallow depth crustal sediments. The microstructure, namely effective porosity and effective specific surface, is investigated using image processing. We furthermore determine flow properties like hydraulic tortuosity and permeability using both experimental measurements and numerical simulations. By fitting microstructural and flow properties to porosity, we obtain a modified Kozeny-Carman equation for isotropic low-porosity media, that can be used to simulate permeability in large-scale numerical models. To verify the modified Kozeny-Carman equation we compare it to the numerically computed and experimentally measured permeability values.</p> </div> </div> </div>

Simulation of the Onset of Gas Entrainment From a CANDU Reactor Channel Under LOCA Conditions: II

2005 ◽  
Author(s):  
T. Ahmad ◽  
I. Hassan
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Theoretical Investigation ◽  
Numerical Models ◽  
Reactor Channel ◽  
Gas Entrainment ◽  
Single Discharge ◽  
Wide Range

An experimental investigation has been carried out to simulate the onset of gas entrainment phenomenon from a stratified region through branches located on a semi-circular wall configuration, in close dimensional resemblance with a CANDU header-feeder system. New experimental data for the onset of gas entrainment was developed during single and multiple discharge from an air/water stratified region over a wide range of Froude numbers (0 to 100), in order to thoroughly understand the onset of gas entrainment phenomenon. The present data is necessary in validating the analytical and numerical models of the onset of gas entrainment, particularly at low Froude numbers. Part I of this paper, Andaleeb et al. (2005), provides the theoretical investigation of the single discharge case.

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