scholarly journals Time-Resolved PIV Measurements and Turbulence Characteristics of Flow Inside an Open-Cell Metal Foam

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3566
Author(s):  
Youngwoo Kim ◽  
Chanhee Moon ◽  
Omid Nematollahi ◽  
Hyun Dong Kim ◽  
Kyung Chun Kim
Keyword(s):  
3D Printing ◽  
Metal Foam ◽  
Complex Geometry ◽  
Flow Characteristics ◽  
Metal Foams ◽  
Transverse Motion ◽  
Post Processing ◽  
Processing Methods ◽  
Time Resolved ◽  
Open Cell

Open-cell metal foams are porous medium for thermo-fluidic systems. However, their complex geometry makes it difficult to perform time-resolved (TR) measurements inside them. In this study, a TR particle image velocimetry (PIV) method is introduced for use inside open-cell metal foam structures. Stereolithography 3D printing methods and conventional post-processing methods cannot be applied to metal foam structures; therefore, PolyJet 3D printing and post-processing methods were employed to fabricate a transparent metal foam replica. The key to obtaining acceptable transparency in this method is the complete removal of the support material from the printing surfaces. The flow characteristics inside a 10-pore-per-inch (PPI) metal foam were analyzed in which porosity is 0.92 while laminar flow condition is applied to inlet. The flow inside the foam replica is randomly divided and combined by the interconnected pore network. Robust crosswise motion occurs inside foam with approximately 23% bulk speed. Strong influence on transverse motion by metal foam is evident. In addition, span-wise vorticity evolution is similar to the integral time length scale of the stream-wise center plane. The span-wise vorticity fluctuation through the foam arrangement is presented. It is believed that this turbulent characteristic is caused by the interaction of jets that have different flow directions inside the metal foam structure. The finite-time Lyapunov exponent method is employed to visualize the vortex ridges. Fluctuating attracting and repelling material lines are expected to enhance the heat and mass transfer. The results presented in this study could be useful for understanding the flow characteristics inside metal foams.

Experimental and numerical thermal analysis of open-cell metal foams developed through a topological optimization and 3D printing process

2018 ◽  
Vol 83 (1) ◽  
pp. 10904 ◽  
Author(s):  
Abdelatif Merabtine ◽  
Nicolas Gardan ◽  
Julien Gardan ◽  
Houssem Badreddine ◽  
Chuan Zhang ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
3D Printing ◽  
Numerical Simulations ◽  
Lattice Model ◽  
Metal Foam ◽  
Complex Geometry ◽  
Metal Foams ◽  
Topological Optimization ◽  
Plaster Mold ◽  
Open Cell

This study focuses on the thermal analysis and comparing a lattice model and an optimized model of open-cell metal foams manufactured thanks to a metal casting process. The topological optimization defines the complex geometry through thermal criteria and a plaster mold reproduces it in 3D printing to be used in casting. The study of the thermal behavior conducted on the two open foam metal structures is performed based on several measurements, as well as numerical simulations. It is observed that the optimized metal foam presented less and non-homogenous local temperature than the lattice model with the gap of about 10 °C between both models. The pore size and porosity significantly affect the heat transfer through the metal foam. The comparison between numerical simulations and experimental results regarding the temperature fields shows a good agreement allowing the validation of the developed three-dimensional model based on the finite element method.

scholarly journals PIV measurement of complex flow characteristics in open-cell metal foam replica

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Minsin Kim ◽  
Youngwoo Kim ◽  
Sajjad Hosseini ◽  
Kyung Chun Kim
Keyword(s):  
Reynolds Number ◽  
Metal Foam ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Complex Flow ◽  
Time Resolved ◽  
Open Cell ◽  
Flow Disturbances ◽  
Piv Measurement ◽  
Inlet Conditions

Time-resolved 2-D particle image velocimetry was used to study on turbulent flow characteristics inside an open-cell metal foam under the laminar and turbulent inlet conditions. A study on the effect of Reynolds number was conducted with different three channel Reynolds numbers, 1000, 5000 and 10000. Uniform upstream flow is divided by the pore network of metal foam and it is found that there are flow disturbances induced by metal foam structure even at a laminar inlet condition. It is confirmed that there is a similarity of the preferred flow path flows take regardless of Reynolds number.

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.

The Effects of Compression and Pore Size Variations on the Liquid Flow Characteristics in Metal Foams

2001 ◽  
Vol 124 (1) ◽  
pp. 263-272 ◽  
Author(s):  
K. Boomsma ◽  
D. Poulikakos
Keyword(s):  
Flow Characteristics ◽  
Maximum Flow ◽  
Metal Foams ◽  
Heat Sinks ◽  
Convection Heat ◽  
Hydraulic Characteristics ◽  
Aluminum Foams ◽  
Transitional Regime ◽  
Open Cell ◽  
Flow Velocities

Open-cell aluminum foams were investigated using water to determine their hydraulic characteristics. Maximum fluid flow velocities achieved were 1.042 m/s. The permeability and form coefficient varied from 2.46×10−10 m2 and 8701 m−1 to 3529×10−10 m2 and 120 m−1, respectively. It was determined that the flowrate range influenced these calculated parameters, especially in the transitional regime where the permeability based Reynolds number varied between unity and 26.5. Beyond the transition regime where ReK≳30, the permeability and form coefficient monotonically approached values which were reported as being calculated at the maximum flow velocities attained. The results obtained in this study are relevant to engineering applications employing metal foams ranging from convection heat sinks to filters and flow straightening devices.

Preliminary NVH Characterization of Metal Foam-Polymer Interpenetrating Phase Composites

2009 ◽  
Author(s):  
Satish Sharma ◽  
Nassif E. Rayess ◽  
Nihad Dukhan
Keyword(s):  
Mathematical Model ◽  
Thermal Stability ◽  
Hybrid Material ◽  
Aluminum Foam ◽  
Metal Foam ◽  
Dynamic Properties ◽  
Metal Foams ◽  
Thermoplastic Polymer ◽  
Open Cell

The damping and basic dynamic properties of a novel type of multifunctional hybrid material known as Metal Foam-Polymer Composite are investigated. This material is obtained by injection molding a thermoplastic polymer through an open cell Aluminum Foam, in essence creating two contiguous morphologies; an Aluminum Foam interconnected “skeleton” with the open pores filled with a similarly interconnected polymer substructure. This coexistence of both materials allows each to contribute its salient properties (e.g. the plastics contributing surface toughness and the metal foams contributing thermal stability). Basic damping testing results are presented for various Aluminum Foam porosities and pore sizes as well as for three types of polymers. A basic mathematical model of the damping is also presented. The integrity of the interface between the Aluminum Foam and the Polymer is discussed in terms of its effect on the overall material damping.

Pore-Level Numerical Simulation of Open-Cell Metal Foams With Application to Aero Engine Separators

2014 ◽  
Author(s):  
Thiago Piazera de Carvalho ◽  
Hervé P. Morvan ◽  
David Hargreaves
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Porous Medium ◽  
Pressure Drop ◽  
Metal Foam ◽  
Metal Foams ◽  
Open Cell ◽  
X Ray ◽  
Pore Level ◽  
Aero Engines

In aero engines, the oil and air interaction within bearing chambers creates a complex two-phase flow. Since most aero engines use a close-loop oil system and releasing oil out is not acceptable, oil-air separation is essential. The oil originates from the engine transmission, the majority of which is scavenged out from the oil pump. The remainder exits via the air vents, where it goes to an air oil separator called a breather. In metal-foam-style breathers separation occurs by two physical processes. Firstly the largest droplets are centrifuged against the separator walls. Secondly, smaller droplets, which tend to follow the main air path, pass through the metal foam where they ideally should impact and coalesce on the material filaments and drift radially outwards, by the action of centrifugal forces. Although these devices have high separation efficiency, it is important to understand how these systems work to continue to improve separation and droplet capture. One approach to evaluate separation effectiveness is by means of Computational Fluid Dynamics. Numerical studies on breathers are quite scarce and have always employed simplified porous media approaches where a momentum sink is added into the momentum equations in order to account for the viscous and/or inertial losses due to the porous zone [1]. Furthermore, there have been no attempts that the authors know of to model the oil flow inside the porous medium of such devices. Normally, breathers employ a high porosity open-cell metal foam as the porous medium. The aim of this study is to perform a pore-level numerical simulation on a representative elementary volume (REV) of the metal foam with the purpose of determining its transport properties. The pore scale topology is represented firstly by an idealized geometry, namely the Weaire-Phelan cell [2]. The pressure drop and permeability are determined by the solution of the Navier-Stokes equations. Additionally, structural properties such as porosity, specific surface area and pore diameter are calculated. The same procedure is then applied to a 3D digital representation of a metallic foam sample generated by X-ray tomography scans [3]. Both geometries are compared against each other and experimental data for validation. Preliminary simulations with the X-ray scanned model have tended to under predict the pressure drop when compared to in-house experimental data. Additionally, the few existing studies on flow in metal foams have tended to consider laminar flow; this is not the case here and this also raises the question that Reynolds-averaged turbulence models might not be well suited to flows at such small scales, which this paper considers.

Experimental and numerical investigation on the effective thermal conductivity of stochastic structure

2019 ◽  
Vol 9 (8) ◽  
pp. 861-871
Author(s):  
Milad Saljooghi ◽  
Younes Bakhshan ◽  
Saeid Niazi ◽  
Jamshid Khorshidi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Metal Foam ◽  
Metal Foams ◽  
Open Cell ◽  
Geometrical Properties ◽  
Copper Aluminum ◽  
Thermo Physical Properties ◽  
Modern Technologies

The Conception of thermo-physical properties of porous materials is a challenging task for scientists to conquer. The open cell metal foam increases heat transfer while energy dissipation, dimension and density of them which are constraints for modern technologies significantly reduce. In the present study, the open cell metal foams with four kinds of structures have been investigated numerically and experimentally and the effective thermal conductivity (ETC) of them have been extracted with using different base fluids such as water, air and paraffin. Also, various metals have been considered copper, aluminum, nickel and silver. Finally, a validated correlation for calculation of ETC of open cell metal foams has been developed which is function of thermal conductivity of fluid and metal, porosity and geometrical properties of pore that is applicable for all open cell metal foam approximately. The results show, good agreements between the modeling results and experimental data.

scholarly journals Simulation of Thermal Transport in Open-Cell Metal Foams: Effect of Periodic Unit Cell Structure

2006 ◽  
Author(s):  
Shankar Krishnan ◽  
Suresh V. Garimella ◽  
Jayathi Y. Murthy
Keyword(s):  
Thermal Transport ◽  
Pore Space ◽  
Cell Structure ◽  
Flow Characteristics ◽  
Metal Foams ◽  
Unit Cube ◽  
Unit Cell ◽  
Face Centered Cubic ◽  
Open Cell ◽  
Periodic Unit Cell

Direct simulation of thermal transport in open-cell metal foams is conducted using different periodic unit cell geometries. The periodic unit cell structures are constructed by assuming the pore space to be spherical and subtracting the pore space from a unit cube of the metal. Different types of packing arrangement for spheres are considered - Body Centered Cubic, Face Centered Cubic, and the A15 lattice (similar to a Weaire-Phelan unit cell) - which give rise to different foam structures. Effective thermal conductivity, pressure drop and Nusselt number are computed by imposing periodic boundary conditions for aluminum foams saturated with air or water. The computed values compare well with existing experimental measurements and semi-empirical models for porosities greater than 80%. The effect of different foam packing arrangements on the computed thermal and fluid flow characteristics is discussed. The capabilities and limitations of the present approach are identified.

Effect of thickness and thermal conductivity of metal foams filled in a vertical channel – a numerical study

2019 ◽  
Vol 29 (1) ◽  
pp. 184-203 ◽  
Author(s):  
Banjara Kotresha ◽  
N. Gnanasekaran
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Metal Foam ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Vertical Channel ◽  
Metal Foams ◽  
Heat Transfer Analysis ◽  
Transfer Model ◽  
Content Type

PurposeThis paper aims to discuss about the two-dimensional numerical simulations of fluid flow and heat transfer through high thermal conductivity metal foams filled in a vertical channel using the commercial software ANSYS FLUENT.Design/methodology/approachThe Darcy Extended Forchheirmer model is considered for the metal foam region to evaluate the flow characteristics and the local thermal non-equilibrium heat transfer model is considered for the heat transfer analysis; thus the resulting problem becomes conjugate heat transfer.FindingsResults obtained based on the present simulations are validated with the experimental results available in literature and the agreement was found to be good. Parametric studies reveal that the Nusselt number increases in the presence of porous medium with increasing thickness but the effect because of the change in thermal conductivity was found to be insignificant. The results of heat transfer for the metal foams filled in the vertical channel are compared with the clear channel in terms of Colburn j factor and performance factor.Practical implicationsThis paper serves as the current relevance in electronic cooling so as to open up more parametric and optimization studies to develop new class of materials for the enhancement of heat transfer.Originality/valueThe novelty of the present study is to quantify the effect of metal foam thermal conductivity and thickness on the performance of heat transfer and hydrodynamics of the vertical channel for an inlet velocity range of 0.03-3 m/s.

Tensile Properties of Processed 3D Printer ZP150 Powder Material

2013 ◽  
Vol 699 ◽  
pp. 813-816 ◽  
Author(s):  
Saleh H. Gharaie ◽  
Yos Morsi ◽  
S.H. Masood
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Tensile Properties ◽  
Powder Material ◽  
Powder Materials ◽  
Post Processing ◽  
Infiltration Process ◽  
Processing Methods ◽  
Powder Bed ◽  
Rp Process

3D Printing is one of the few powder-bed type rapid prototyping (RP) technologies, which allows fabrication of parts using powder materials. Understanding of mechanical properties of 3D parts made by this process is essential to explore more applications of this technology. In general, the mechanical properties of many RP produced parts depend on the process parameters andalso on post-processing methods of that RP process. Very few studies have been made to characterize the mechanical properties of 3D Printing processed parts. This paper presents an experimental investigation on how tensile properties of parts fabricated by 3D Printing is affected by 3D Printing build orientation, and by post-processing methods of infiltration process and drying of parts. Results obtained forvarious parameters are compared to investigate the optimum procedure to achieve the highest tensile strength using ZP150 powder material.

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