scholarly journals Modeling of the Effective Permittivity of Open-Cell Ceramic Foams Inspired by Platonic Solids

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7446
Author(s):  
Jesus Nain Camacho Hernandez ◽  
Guido Link ◽  
Markus Schubert ◽  
Uwe Hampel
Keyword(s):  
Effective Permittivity ◽  
Dielectric Materials ◽  
Industrial Applications ◽  
Platonic Solids ◽  
Open Cell ◽  
Ceramic Foams ◽  
Foam Morphology ◽  
Rigorous Description ◽  
Open Cell Foams ◽  
Solid Foams

Open-cell solid foams are rigid skeletons that are permeable to fluids, and they are used as direct heaters or thermal dissipaters in many industrial applications. Using susceptors, such as dielectric materials, for the skeleton and exposing them to microwaves is an efficient way of heating them. The heating performance depends on the permittivity of the skeleton. However, generating a rigorous description of the effective permittivity is challenging and requires an appropriate consideration of the complex skeletal foam morphology. In this study, we propose that Platonic solids act as building elements of the open-cell skeletal structures, which explains their effective permittivity. The new, simplistic geometrical relation thus derived is used along with electromagnetic wave propagation calculations of models that represent real foams to obtain a geometrical, parameter-free relation, which is based only on foam porosity and the material’s permittivity. The derived relation facilitates an efficient and reliable estimation of the effective permittivity of open-cell foams over a large range of porosity.

Development of Bio-Based Foams With Improved Acoustic and Mechanical Performance

2012 ◽  
Author(s):  
Shahrzad Ghaffari Mosanenzadeh ◽  
Hani E. Naguib ◽  
Chul B. Park ◽  
Noureddine Atalla
Keyword(s):  
Mechanical Characteristics ◽  
Mechanical Performance ◽  
Water Soluble ◽  
Huge Amount ◽  
Open Cell ◽  
Acoustic Performance ◽  
Foam Morphology ◽  
Open Cell Foams ◽  
Weak Structure ◽  
Highly Porous

Interest in noise control has been growing in recent years and efforts are under way to improve the acoustic performance of existing sound absorbers and also to replace the non-recyclable ones with environmentally friendly materials. Present study describes the research on fabrication, improvement of acoustic absorption and enhancement of mechanical strength of bio-based open-cell foams. Through this study, highly porous open-cell Polylactide (PLA) foams were fabricated by a new fabrication method combining particulate leaching technique and compression molding. Foamed structures were fabricated with PLA and Polyethylene glycol (PEG) with salt as the particulate. Pore size of the foam was controlled by salt particulates and higher interconnectivity was achieved by the co-continuous blending morphology of PLA matrix with water-soluble PEG. As a result of novel secondary porous structure, acoustic performance of PLA foams was successfully improved. One issue with application of bio-based open-cell foams is the weak structure. To improve mechanical characteristics of PLA foams, different polymer composites of PLA and Polyhydroxyalkanoate (PHA) were foamed and characterized in terms of acoustic performance, mechanical properties and foam morphology. Polymers used in this study are bio-based which is of great importance considering huge amount of foams used as acoustic absorbers in various industries.

Analysis of Heat Transfer and Pressure Drop Through Idealized Open Cell Ceramic Foams: Comparison Between Kelvin and Weaire-Phelan Cell Structures

2013 ◽  
Author(s):  
N. Bianco ◽  
S. Cunsolo ◽  
W. K. S. Chiu ◽  
V. Naso ◽  
A. Migliozzi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Open Source Software ◽  
Surface Evolver ◽  
Open Cell ◽  
Ceramic Foams ◽  
Cell Structures ◽  
Cell Architecture ◽  
Cell Dimensions ◽  
Open Cell Foams

In the applications of metal foams, the knowledge of the thermal transport properties is of primary importance. Thermal properties of a foam heavily depend on its microstructure. However, the influence of some geometric characteristics of the foam cells on their properties is far from being understood. Foam models are promising tools to study the above said effects. The effect of the cell architecture on heat transfer and pressure drop in open cell foams is investigated numerically using two foam models. The Kelvin and the Weaire-Phelan foam models are developed in an open source software “Surface Evolver”. Heat transfer and pressure drop in samples with different porosities and cell dimensions are studied using COMSOL® Multiphysics. Finally, a comparison between the numerical results obtained from two foam models is carried out in order to evaluate the feasibility to substitute the Weaire-Phelan foam structure, which is more complex and computationally heavier, with the simpler Kelvin foam representation.

Foam Structure: From Soap Froth to Solid Foams

MRS Bulletin ◽  
2003 ◽  
Vol 28 (4) ◽  
pp. 275-278 ◽  
Author(s):  
Andrew M. Kraynik
Keyword(s):  
Three Dimensional ◽  
Edge Length ◽  
Surface Evolver ◽  
Foam Structure ◽  
Open Cell ◽  
Liquid Foams ◽  
Virtual Reconstruction ◽  
Open Cell Foams ◽  
Solid Foams ◽  
Polyhedral Cells

AbstractThe properties of solid foams depend on their structure, which usually evolves in the fluid state as gas bubbles expand to form polyhedral cells. The characteristic feature of foam structure—randomly packed cells of different sizes and shapes—is examined in this article by considering soap froth. This material can be modeled as a network of minimal surfaces that divide space into polyhedral cells. The cell-level geometry of random soap froth is calculated with Brakke's Surface Evolver software. The distribution of cell volumes ranges from monodisperse to highly polydisperse. Topological and geometric properties, such as surface area and edge length, of the entire foam and individual cells, are discussed. The shape of struts in solid foams is related to Plateau borders in liquid foams and calculated for different volume fractions of material. The models of soap froth are used as templates to produce finite element models of open-cell foams. Three-dimensional images of open-cell foams obtained with x-ray microtomography allow virtual reconstruction of skeletal structures that compare well with the Surface Evolver simulations of soap-froth geometry.

State-of-the-Art of Pressure Drop in Open-Cell Porous Foams: Review of Experiments and Correlations

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Prashant Kumar ◽  
Frédéric Topin
Keyword(s):  
Pressure Drop ◽  
High Performance ◽  
Industrial Applications ◽  
Morphological Parameters ◽  
Empirical Correlations ◽  
Open Cell ◽  
Substantial Progress ◽  
Successful Design ◽  
Open Cell Foams ◽  
Microporous Media

Foam structures are a class of modern microporous media that possesses high thermal conductivity, large accessible specific surface area, and high porosities. Nowadays, industrial applications, such as filtration, heat exchange and chemical reaction, etc., utilize porous media such as open-cell foams. Knowledge of pressure drop induced by these foam matrices is essential for successful design and operation of high-performance industrial systems. The homogenized pressure drop data in the literature are widely dispersed (up two orders of magnitude) despite numerous researches has been conducted since two decades. Most of the empirical pressure drop correlations were derived using Ergun-like approach. In this view, a careful evaluation of empirical correlations as well as the relationship of intrinsic flow law characteristics (permeability and inertia coefficient) with morphological parameters is imperative. This paper presents the start-of-the-art of various pressure drop correlations as well as highlights the ambiguities and inconsistencies in various definitions of several key parameters. The applicability of the empirical correlations presented in the literature was examined by comparing them against numerically calculated pressure drop data of open-cell foams (metal and ceramic) for the porosities ranging from 0.60 up to 0.95. A comprehensive study has been conducted to identify the reasons of dispersed pressure drop data in the literature. Although substantial progress has been made in the field of fluid flow in open-cell foams, it is yet difficult to predict pressure drop data from a given set of morphological parameters.

scholarly journals Macroscopic modeling of open cell foams

PAMM ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Stephan Kirchhof ◽  
Alfons Ams
Keyword(s):  
Open Cell ◽  
Macroscopic Modeling ◽  
Open Cell Foams

Geometry Dependent Effective Elastic Properties of Open-Cell Foams Based on Kelvin Cell Models**

2013 ◽  
Vol 15 (12) ◽  
pp. 1292-1298 ◽  
Author(s):  
Johannes Storm ◽  
Martin Abendroth ◽  
Dongshuang Zhang ◽  
Meinhard Kuna
Keyword(s):  
Elastic Properties ◽  
Cell Models ◽  
Open Cell ◽  
Effective Elastic Properties ◽  
Open Cell Foams
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