Analytical Transport Network Theory for Onsager, Coupled Flows: Part 1—Channel-Scale Modeling of Linear, Electrokinetic Flow

2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Alex P. Cocco ◽  
Kyle N. Grew
Keyword(s):  
Three Dimensional ◽  
Initial Step ◽  
Transport Network ◽  
Scale Model ◽  
Coupled Flow ◽  
Electrokinetic Flow ◽  
Element Analysis ◽  
Onsager Reciprocity ◽  
Flow Phenomena ◽  
Flow Through

Abstract The analytical transport network (ATN) model for flow through microstructural networks is extended to linearly coupled flows subject to Onsager reciprocity. Electrokinetic flow is used as an example system. Through the extension, we gain an improved understanding of if, and how, morphology and topology influence coupled flow systems differently than un-coupled flows. In Part 1, a channel-scale model is developed to describe electrokinetic flow through a channel of arbitrary morphology. The analytical model agrees well with finite element analysis (FEA), but is significantly less expensive in terms of computational resources, and, furthermore, offers general insight into morphology's additional influence on coupled flows relative to uncoupled flows. In Part 2, we exploit these savings to develop a computationally economical, network-scale model and associated algorithm for its implementation to voxel-based three-dimensional images. Included in the algorithm is a means for rapidly calculating a structure's tortuosity factor. This modeling effort represents an important initial step in extending the ATN approach to coupled flow phenomena relevant to emerging technologies that rely on heterogeneous, hierarchical materials.

Analytical Transport Network Theory for Onsager, Coupled Flows: Part 2—Network-Scale Modeling of Linear, Electrokinetic Flow

2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Alex P. Cocco ◽  
Kyle N. Grew
Keyword(s):  
Three Dimensional ◽  
Initial Step ◽  
Transport Network ◽  
Scale Model ◽  
Computationally Efficient ◽  
Coupled Flow ◽  
Electrokinetic Flow ◽  
Network Scale ◽  
Energy Conversion And Storage ◽  
Storage Technologies

Abstract The analytical transport network (ATN) model was developed to study transport through heterogeneous and hierarchical microstructural networks. Here, ATN is extended to electrokinetic flow, a linear, coupled flow that satisfies Onsager’s reciprocity relations. In Part 1, a channel-scale model was developed to describe electrokinetic flow through a channel of arbitrary morphology. In Part 2, we exploit the computational economy of the channel-scale model to develop an efficient network-scale model of electrokinetic flow in large, geometrically complex material structures. The corresponding algorithm for applying the theory to voxel-based, three-dimensional (3D) images is automated and computationally efficient. In addition, it provides a means for rapidly obtaining a structure’s tortuosity factor from a 3D image. We outline the manner in which morphology and topology exerts an additional influence on electrokinetic flow relative to pure conduction and viscous fluid flow. The effort represents an important initial step in extending the ATN approach to a broader range of linear and eventually nonlinear coupled flow phenomena. The extension is relevant to a number of technological fields, including emerging energy conversion and storage technologies.

Finite Element Analysis of Behavior of Bolted Flange Connections under Bending Loading

2010 ◽  
Vol 26-28 ◽  
pp. 1168-1171
Author(s):  
Bin Wu ◽  
Tao Wang ◽  
Chao Xu ◽  
Bing Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Initial Step ◽  
Nonlinear Phenomena ◽  
Sharp Change ◽  
Element Analysis ◽  
Bolted Flange ◽  
Bending Loading

Only a limited number of experimental and analysis reports exist concerning bolted flange connections under bending loading. In order to investigate the complex nonlinear phenomena, three dimensional elasto-plastic finite element analyses are performed. In those analyses, frictional contact model with small sliding option is applied between contacting pair surfaces of all connecting elements. Bolt pretension force is introduced in the initial step of analysis. From this study, the following results are obtainted:1) proposed finite element analysis method can be applicable to estimate complex nonlinear behavior of bolted flange type connections; 2) There is a sharp change in bending stiffness during loading, and lateral slip between two jointed flanges cause the bolt to carry shear load. The design of bolted joints should consider the interaction among cylinders, flanges and bolts.

Three-Dimensional Finite Element Analysis of a Scale Model Nuclear Containment Vessel

1986 ◽  
Vol 108 (3) ◽  
pp. 320-329
Author(s):  
G. Derbalian ◽  
G. Fowler ◽  
J. Thomas
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ultimate Strength ◽  
Three Dimensional ◽  
Scale Model ◽  
Element Analysis ◽  
Containment Vessel ◽  
Nuclear Containment ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Current design procedures for nuclear containment vessels are based on elastic analyses. Though such techniques are adequate under normal operating conditions, if the potential risks associated with extreme environments or accident conditions are to be assessed, knowledge of the ultimate capacity of the containment structure is essential. A key technical question is whether penetrations, such as personnel hatches, weaken the containment structure. In this paper, the maximum pressure sustained by a scale model, steel, nuclear containment vessel with a penetration is determined using a three-dimensional finite element analysis. To assess containment strength, a clean shell is analyzed in closed form for its ultimate strength, and the solution is then compared with finite element results for a structure that has a penetration. The comparison shows that the personnel hatch penetration does not reduce the ultimate strength of the containment structure. In this paper, it is assumed that the materials have no flaws and welded joints are perfectly bonded. Cracks in the structure, which would degrade its strength, are not considered.

scholarly journals Measurement of Flow Phenomena in a Lower Plenum Model of a Prismatic Gas-Cooled Reactor

2008 ◽  
Author(s):  
Hugh M. McIlroy ◽  
Donald M. McEligot ◽  
Robert J. Pink
Keyword(s):  
Turbulent Flow ◽  
National Laboratory ◽  
Three Dimensional ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Scale Model ◽  
Working Fluid ◽  
Mean Velocity ◽  
Standard Problem ◽  
Flow Phenomena

Mean-velocity-field and turbulence data are presented that measure turbulent flow phenomena in an approximately 1:7 scale model of a region of the lower plenum of a typical prismatic gas-cooled reactor (GCR) similar to a General Atomics Gas-Turbine-Modular Helium Reactor (GTMHR) design. The data were obtained in the Matched-Index-of-Refraction (MIR) facility at Idaho National Laboratory (INL) and are offered for assessing computational fluid dynamics (CFD) software. This experiment has been selected as the first Standard Problem endorsed by the Generation IV International Forum. Results concentrate on the region of the lower plenum near its far reflector wall (away from the outlet duct). The flow in the lower plenum consists of multiple jets injected into a confined cross flow — with obstructions. The model consists of a row of full circular posts along its centerline with half-posts on the two parallel walls to approximate geometry scaled to that expected from the staggered parallel rows of posts in the reactor design. The model is fabricated from clear, fused quartz to match the refractive-index of the working fluid so that optical techniques may be employed for the measurements. The benefit of the MIR technique is that it permits optical measurements to determine flow characteristics in complex passages in and around objects to be obtained without locating intrusive transducers that will disturb the flow field and without distortion of the optical paths. An advantage of the INL system is its large size, leading to improved spatial and temporal resolution compared to similar facilities at smaller scales. A three-dimensional (3-D) Particle Image Velocimetry (PIV) system was used to collect the data. Inlet jet Reynolds numbers (based on the jet diameter and the time-mean bulk velocity) are approximately 4,300 and 12,400. Uncertainty analyses and a discussion of the standard problem are included. The measurements reveal developing, non-uniform, turbulent flow in the inlet jets and complicated flow patterns in the model lower plenum. Data include three-dimensional vector plots, data displays along the coordinate planes (slices) and presentations that describe the component flows at specific regions in the model. Information on inlet conditions is also presented.

A Numerical Study of Natural Convection Inside an Automobile Compartment Due to Solar Radiation

2009 ◽  
Author(s):  
Md. Faisal Kader ◽  
Yong-du Jun ◽  
Kum-bae Lee
Keyword(s):  
Fluid Flow ◽  
Solar Radiation ◽  
Numerical Study ◽  
Three Dimensional ◽  
Scale Model ◽  
Design Parameters ◽  
Three Dimensional Model ◽  
Flow And Heat Transfer ◽  
Flow Through ◽  
Paper Address

In summer, the temperature of a parked automobile compartment increases extremely high under a sunny condition. Investigation of this fluid flow and heat transfer characteristics is very important for controlling the effect of major design parameters. This paper address the behavior of fluid flow through convection and air temperature inside a car parked in the sun. The numerical solution was done by a new and operation friendly CFD code – SC/Tetra with a full scale model of a SM3 car and turbulence was modeled by the standard k-ε equation. It can be seen that solar radiation is an important parameter to raise the compartment temperature above the ambient temperature during summer. Numerical analysis of the three-dimensional model predicts a detailed description of fluid flow and temperature distribution driven by the incoming solar radiation (insoaltion) in the passenger compartment.

Numerical Simulation of a Combined Plasma Arc Based on Sequentially Coupled Physics Analysis

2010 ◽  
Vol 129-131 ◽  
pp. 708-713
Author(s):  
Jian Bing Meng ◽  
Xiao Juan Dong ◽  
Wen Ji Xu
Keyword(s):  
Fluid Flow ◽  
Three Dimensional ◽  
Mapping Method ◽  
Variable Step Size ◽  
Plasma Arc ◽  
Step Size ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Flow Phenomena ◽  
Sequential Coupling

A three-dimensional axisymmetric mathematical model, including the influence of the swirl exiting in the plasma torch, was developed to describe the heat transfer and fluid flow within a combined plasma arc. In this model, a mapping method and a meshing method of variable step-size were adopted to mesh the calculation domain and to improve the computational precision. To overcome the problem issuing from a coexistence of non-transferred arc and transfer arc and a complicated interaction between electric, magnetic, heat flow and fluid flow phenomena in the combined plasma arc, a sequential coupling method and a physical environment approach were introduced into the finite element analysis on the behaviors of combined plasma arc. Furthermore, the characteristics of combined plasma arc such as temperature, velocity, current density and electromagnetic force were studied.

Flow in a Centrifugal Fan Impeller at Off-Design Conditions

1984 ◽  
Vol 106 (4) ◽  
pp. 913-919 ◽  
Author(s):  
T. Wright ◽  
K. T. S. Tzou ◽  
S. Madhavan
Keyword(s):  
Three Dimensional ◽  
Internal Flow ◽  
Design Flow ◽  
Experimental Results ◽  
Surface Velocity ◽  
Scale Model ◽  
Valuable Insight ◽  
Centrifugal Fan ◽  
Viscous Effects ◽  
Element Analysis

Predicted and measured surface velocity and pressure distributions in the internal flow channels of a centrifugal fan impeller are presented for volume flow rates between 80 and 125 percent of design flow rate. Predictions are based on a fully three-dimensional, finite element analysis of the inviscid, incompressible blade channel flow. Additional predictions using a conventional quasi-three-dimensional analysis are presented for comparison. Experimental results were developed using extensive blade and sidewall surface pressure taps installed in a scale model of an airfoil-bladed centrifugal fan impeller designed for heavy industrial and power generation applications. The results illustrate the ability of both flow analyses to predict the dominant features of the impeller flow field, including peak blade surface velocities and adverse gradients at flows far from the design point. In addition, the experimental results provide valuable insight into the limiting channel diffusion values for typical centrifugal cascade performance, and the influence of viscous effects as seen in deviations from the ideal flow predictions.

scholarly journals Finite Element Analysis of Three-Dimensional Flow Through a Turbocharger Compressor Wheel

1983 ◽  
Author(s):  
A. Ecer ◽  
H. U. Akay ◽  
S. Mattai
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Numerical Results ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Compressor Wheel ◽  
Choked Flow ◽  
Compressor Rotor ◽  
Mass Flow Rates ◽  
Flow Through

Analysis of three-dimensional, transonic, potential flow through a compressor rotor is investigated using the finite element method. The formulation of the equations and the generation of the corresponding finite element grid are presented. A constant-coefficient solution scheme is applied for the efficient solution of these equations. Numerical results are obtained for the flow through a 5.0” diameter turbocharger compressor wheel. Four different mass flow rates are considered including a transonic, near-choked flow case. Accuracy of the numerical results are tested by comparing with experimental measurements.

A Numerical Analysis of a Mixed Flow Pump

2002 ◽  
Author(s):  
J. Ferna´ndez ◽  
E. Blanco ◽  
C. Santolaria ◽  
T. J. Scanlon ◽  
M. T. Stickland
Keyword(s):  
Flow Rate ◽  
Three Dimensional ◽  
Axial Direction ◽  
Second Order ◽  
Mixed Flow ◽  
Wall Functions ◽  
Flow Phenomena ◽  
Numerical Grid ◽  
Flow Through ◽  
Flow Pump

The rotating passages of turbomachinery contain some very interesting and complex fluid flow phenomena. This paper presents the three-dimensional turbulent flow through the impeller passages and surroundings of a mixed-flow pump. The model has five impeller blades mounted on a conical hub and nine stator blades in a diffuser which brings the diagonally outward flow back to the axial direction. This pump was tested with air, giving a nominal flow-rate of 1.01 m3/s and 250 Pa at 1200 rpm. Temporal discretization has second order accuracy and this is in line with the discretization of convection which is also second order. For turbulence closure the standard k-e model has been applied with conventional wall functions employed at solid surfaces. For this transient, three-dimensional computation, the numerical grid has been decomposed into five separate regions in order to process these in a parallel cluster of five individual PC’s. The results show entirely reasonable correlations with published experimental data as detailed in the flow rate-head comparisons and the numerical / experimental flow fields. These outcomes allow us to confirm that such a complex transient phenomenon may be reasonably captured by employing a commercial CFD code.

Nonlinear Finite Element Analysis of Non-Structural Components Anchorage under Extreme Wind Loads

2019 ◽  
Author(s):  
Sálvio A. ALMEIDA Jr ◽  
Serhan Guner
Keyword(s):  
Finite Element ◽  
Elevated Temperatures ◽  
Concrete Slab ◽  
Three Dimensional ◽  
Nonlinear Finite Element ◽  
Scale Model ◽  
Structural Components ◽  
Element Analysis ◽  
Multi Scale ◽  
Service Load

<p>Steel anchors are widely used to fasten structures and non-structural components (NSC) to rooftop concrete slabs, especially in high-rise buildings. However, several NSC anchorage failures have been observed in the last decades upon the incidence of hurricanes, resulting in loss of service in essential buildings, detachment of the component, and water intrusion, all of which significantly delayed the recovery of the affected communities. From the observed failures, three main mechanisms were identified: steel rupture, concrete breakout, and bond failure. In this study, a three-dimensional nonlinear finite element methodology using a concrete damaged plasticity approach is developed to predict the response of steel anchors installed into a concrete slab. The methodology is verified with experimental results for each failure mechanism and subsequently used to study the effect of service-load concrete cracking and elevated temperatures – common conditions at rooftop level – on the response of the anchors. In addition, a first-of-its-kind multi-scale model of an NSC and its anchorage is created using the proposed methodology to investigate its behavior under dynamic hurricane load application. The findings suggest that these conditions can compromise the performance of NSC or promote its failure.</p>

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