Relative Performance of Body-Fitted and Fictitious Domain Simulations of Flow Through Porous Media

2012 ◽  
Author(s):  
Justin R. Finn ◽  
Sourabh V. Apte
Keyword(s):  
Relative Performance ◽  
Fictitious Domain ◽  
Packed Beds ◽  
Fluid Inertia ◽  
Constraint Force ◽  
Flow Rates ◽  
Macro Scale ◽  
Rigidity Constraint ◽  
Flow Through ◽  
Scale Properties

The relative performance of (i) a body-fitted unstructured grid Navier-Stokes solver [Moin and Apte, AIAA J. 2006], and (ii) a fictitious domain based finite-volume approach [Apte et al. JCP 2009] is examined for simulating flow through packed beds of spheres at moderate flow rates, 50 ≲ Re ≲ 1300. The latter employs non-body conforming Cartesian grids and enforces the no-slip conditions on the pore boundaries implicitly through a rigidity constraint force. At these flow rates, fluid inertia can result in complex steady and unsteady pore scale flow features that influence macro-scale properties. We examine the requirements on both methods to properly capture these features in both simple and complex arrangements of spheres. First, two prototypical test cases of flow through packed beds are studied thoroughly at a range of Reynolds numbers in the inertial flow regime. Next flow through a random packing of 51 spheres at Re = 1322 is simulated using both methods. The suitability of both approaches to the complex configurations observed in large randomly packed beds is discussed.

scholarly journals Analysis of Performance of the Wind-Driven Pulverizing Aerator Based on Average Wind Speeds in the Conditions of Góreckie Lake

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2796
Author(s):  
Andrzej Osuch ◽  
Ewa Osuch ◽  
Stanisław Podsiadłowski ◽  
Piotr Rybacki
Keyword(s):  
Mathematical Model ◽  
Wind Speed ◽  
Water Pump ◽  
Average Wind Speed ◽  
Flow Rates ◽  
Wind Speeds ◽  
Average Wind ◽  
Flow Through ◽  
Analysis Of Performance ◽  
Research Period

In the introduction to this paper, the characteristics of Góreckie lake and the construction and operation of the wind-driven pulverizing aerator are presented. The purpose of this manuscript is to determine the efficiency of the pulverizing aerator unit in the windy conditions of Góreckie Lake. The efficiency of the pulverization aerator depends on the wind conditions at the lake. It was necessary to conduct thorough research to determine the efficiency of water flow through the pulverization segment (water pump). It was necessary to determine the rotational speed of the paddle wheel, which depended on the average wind speed. Throughout the research period, measurements of hourly average wind speed were carried out. It was possible to determine the efficiency of the machine by developing a dedicated mathematical model. The latest method was used in the research, consisting of determining the theoretical volumetric flow rates of water in the pulverizing aerator unit, based on average hourly wind speeds. Pulverization efficiency under the conditions of Góreckie Lake was determined based on 6600 average wind speeds for spring, summer and autumn, 2018. Based on the model, the theoretical efficiency of the machine was calculated, which, under the conditions of Góreckie Lake, amounted to 75,000 m3 per year.

scholarly journals Transient Pressure-Driven Electroosmotic Flow through Elliptic Cross-Sectional Microchannels with Various Eccentricities

Computation ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 27
Author(s):  
Nattakarn Numpanviwat ◽  
Pearanat Chuchard
Keyword(s):  
Laplace Transform ◽  
Electroosmotic Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Mathieu Functions ◽  
Navier Stokes Equations ◽  
Flow Rates ◽  
Elliptic Cross ◽  
Flow Through ◽  
Relative Errors

The semi-analytical solution for transient electroosmotic flow through elliptic cylindrical microchannels is derived from the Navier-Stokes equations using the Laplace transform. The electroosmotic force expressed by the linearized Poisson-Boltzmann equation is considered the external force in the Navier-Stokes equations. The velocity field solution is obtained in the form of the Mathieu and modified Mathieu functions and it is capable of describing the flow behavior in the system when the boundary condition is either constant or varied. The fluid velocity is calculated numerically using the inverse Laplace transform in order to describe the transient behavior. Moreover, the flow rates and the relative errors on the flow rates are presented to investigate the effect of eccentricity of the elliptic cross-section. The investigation shows that, when the area of the channel cross-sections is fixed, the relative errors are less than 1% if the eccentricity is not greater than 0.5. As a result, an elliptic channel with the eccentricity not greater than 0.5 can be assumed to be circular when the solution is written in the form of trigonometric functions in order to avoid the difficulty in computing the Mathieu and modified Mathieu functions.

THE FLOW OF FLUIDS THROUGH ACTIVATED CARBON RODS.

1952 ◽  
Vol 30 (4) ◽  
pp. 348-371 ◽  
Author(s):  
E. A. Flood ◽  
R. H. Tomlinson ◽  
A. E. Leger
Keyword(s):  
Activated Carbon ◽  
Relative Pressure ◽  
End Effects ◽  
Flow Rates ◽  
Frequency Distributions ◽  
Literal Sense ◽  
Fine Grained ◽  
Porous Bodies ◽  
Carbon Rods ◽  
Flow Through

The flow rates of the vapors of benzene, ethyl chloride, diethyl ether, methanol, and water through activated carbon rods have been found to exceed, considerably, flow rates calculated by classical equations. The excess flow rates show maxima in widely different relative pressure regions and are ascribed to flow of adsorbed material. An empirical equation is presented which correlates the observed flow rates with relevant adsorption isotherms. Classical equations of flow through elliptical and rectangular pipes are discussed with reference to flow through fine-grained porous materials. It is shown that equations of the Adzumi type are roughly valid as applied to fine-grained porous bodies, but that without a knowledge of the frequency distributions of pore sizes and shapes, flow data cannot be related to pore dimensions in any literal sense. End effects are discussed.

Electroosmotic flow through packed beds of granular materials

2015 ◽  
Vol 19 (3) ◽  
pp. 693-708 ◽  
Author(s):  
Rakesh Saini ◽  
Matthew Kenny ◽  
Dominik P. J. Barz
Keyword(s):  
Granular Materials ◽  
Electroosmotic Flow ◽  
Packed Beds ◽  
Flow Through

Novel Lightweight Metal Foam Heat Exchangers

2001 ◽  
Author(s):  
David P. Haack ◽  
Kenneth R. Butcher ◽  
T. Kim ◽  
T. J. Lu
Keyword(s):  
Heat Exchange ◽  
Pore Size ◽  
Heat Exchangers ◽  
Metal Foam ◽  
Heat Removal ◽  
Random Orientation ◽  
Flow Rates ◽  
Small Pore ◽  
Complex Heat Exchange ◽  
Flow Through

Abstract An overview of open cell metal foam materials with application to advanced heat exchange devices is presented. The metal foam materials considered consist of interconnected cells in a random orientation. Metal foam materials, manufacture and fabrication into complex heat exchange components are described. Experiments with flat foam panels brazed to copper sheets shows increasing heat removal effectiveness with decreasing product pore size at equivalent coolant flow rates. However, the high-pressure drop associated with flow through small pore-size material makes the use of larger pore size material more attractive.

The Gas Permeability of Plasma Sprayed Ceramic Coatings

1997 ◽  
Author(s):  
A.C. Fox ◽  
T.W. Clyne
Keyword(s):  
Gas Permeability ◽  
Test Procedure ◽  
Ceramic Coatings ◽  
Hydrogen Gas ◽  
Steady State Flow ◽  
Flow Rates ◽  
Specific Permeability ◽  
Measured Flow ◽  
Flow Through ◽  
Plasma Sprayed

Abstract A simple test procedure, based on steady state flow through a membrane, has been developed for measurement of the gas permeability of specimens over a range of temperature. The reliability of this equipment has been verified by testing solid disks containing single perforations and comparing the measured flow rates with those expected on the basis of laminar flow. Coatings of yttria-stabilised zirconia have been produced by plasma spraying in vacuum and in air. The specific permeability of these coatings has been measured at temperatures ranging up to 600°C, using hydrogen gas. It has been found that permeability is increased for coatings produced with longer stand-off distances and at higher pressures. Porosity levels have been measured using densitometry and microstructural features have been examined using SEM. A model has been developed for prediction of the permeability from such microstructural features, based on percolation theory. Agreement between predicted and measured permeabilities is good, although it is clear that more comprehensive data are needed in order to validate the model systematically.

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