Forced convection through open cell foams based on homogenization approach: Steady state analysis

Vijay, Dig; Goetze, Pitt; Wulf, Rhena; Groß, Ulrich

doi:10.1016/j.ijthermalsci.2015.07.017

Cited by 13 publications

(13 citation statements)

References 34 publications

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“…For the hydraulic tortuosity, a value of 1.10 was determined, which is relatively low in comparison to the values reported for open‐cell foams, indicating a homogenous material distribution with few or no closed windows. This is also reflected by the Darcy and Forchheimer coefficients of 2.56 × 10 −7 m 2 and 3.97 × 10 −3 m, respectively, which align with the upper range of literature values . Using the Darcy–Forchheimer law, the inertial contribution to the overall pressure drop was estimated as 70% for the conditions present in the experiment.…”

Section: Resultssupporting

confidence: 80%

“…This is also reflected by the Darcy and Forchheimer coefficients of 2.56 Â 10 À7 m 2 and 3.97 Â 10 À3 m, respectively, which align with the upper range of literature values. [34,35] Using the Darcy-Forchheimer law, the inertial contribution to the overall pressure drop was estimated as 70% for the conditions present in the experiment. This and the strut Reynolds number of 70 suggest a mildly transient flow inside the filter, which was also observed in the form of small velocity fluctuations at the filter outlet.…”

Section: Numerical Simulationmentioning

confidence: 99%

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Experimental Investigations of the Depth Filtration inside Open‐Cell Foam Filters Supported by High‐Resolution Computed Tomography Scanning and Pore‐Scale Numerical Simulations

et al. 2019

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The removal of nonmetallic inclusions from metal melts is a crucial step in producing high‐quality castings that have to meet strict requirements regarding strength, toughness, and machinability. To separate the unwanted impurities, the liquid metal is usually passed through ceramic foam filters (CFF), in which the inclusions adhere to the surface of a complex strut network. The development of improved CFF structures requires a good understanding of the physical phenomena involved in the filtration process. In this respect, an experimental investigation of the real system is challenging, due to the opacity of the melt, high temperature, and the presence of a protective atmosphere. Therefore, the present study relies on water model experiments, which are conducted for different pore counts and flow velocities. To achieve a high degree of similarity to the real system, the wetting properties of the filters and particles are adjusted accordingly. Experimentally evaluated filtration efficiencies are compared with predictions obtained from a detailed numerical model that considers the CFF geometry, which is digitized using 3D X‐Ray micro‐computed tomography, and previously measured particle adhesion forces. The results suggest that a considerable fraction of particles does not remain attached after collision with the CFF struts.

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Section: Resultssupporting

confidence: 80%

Section: Numerical Simulationmentioning

confidence: 99%

Experimental Investigations of the Depth Filtration inside Open‐Cell Foam Filters Supported by High‐Resolution Computed Tomography Scanning and Pore‐Scale Numerical Simulations

et al. 2019

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“…For this reason, based on the experimental data, the numerical inversion method has been used to obtain the volumetric heat transfer coefficient [19]. Based on this principle, the steady-state method in which a heat source is fixed to a wall-heated foam material and the single-blow method in which a fluid heated or cooled foam material are proposed [20,21]. Under the experimental conditions, the steady-state method has a temperature gradient in the channel, and the volumetric heat transfer coefficient mostly depends on the thermal conductivity of the solid phase.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Study on Convective Heat Transfer Characteristics in Foam Materials

Han

Yang

Wu³

et al. 2020

Energies

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Foam materials are widely used in heat exchange because of their high porosity and large specific surface area. Correctly characterizing heat transfer characteristics is the key to ensuring efficient heat transfer. In this paper, single-blow transient test technology is used to experimentally measure the temperature. Silicon carbide ceramics with various thicknesses ranging from 30 to 105 mm and different pore structures were used in the experiments. The test was carried out at the velocity ranging from 0.5 to 1.8 m/s. The air temperature distributions of the inlet and outlet were obtained by processing the experimental data, and the regularity of the average volumetric heat transfer coefficient was obtained and analyzed. Subsequently, the simplified tetrakaidecahedron models with a porosity of 0.85 and 0.75 were used to analyze the heat transfer characteristics. The local thermal equilibrium and local thermal non-equilibrium at the pore scale were analyzed. By comparing the simulation with the experiment, it shows that the larger thickness affects local thermal equilibrium and leads to a decrease in the volumetric heat transfer coefficient. The conclusion can be used to guide the optimization of the design of foam material-mediated heat exchange equipment.

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“…The volumetric heat transfer coefficient was established by fitting the experimental data. Vijay [20] experimentally determined the volumetric heat transfer coefficient for alumina foams with different geometric parameters based on the transient heat transfer. To explore the volumetric solar air receiver, Fend [21] and Xia [22] experimentally investigated the convective heat transfer inside the ceramic foam (Xia [22] also studied Cu and Ni foam), and empirical correlations were unsurprisingly proposed.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Convective Heat Transfer and Local Thermal Equilibrium in Ceramic Foam

Han

et al. 2020

Processes

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Foam materials have been widely used in various industrial applications, where higher and higher heat and mass transfer performances are pursued. However, the mechanism of many factors on the heat transfer performances is still unclear. The main purpose of this article is to investigate how the porous properties, porosity, cell size and the sample thickness affect the volumetric convective heat transfer. In this study, the single-blow method is used to determine the volumetric heat transfer coefficient of ceramics foam in the temperature range from 283 K to 323 K. In particular, sensitivity analysis of the foam porosity, cell size, velocity and the sample thickness on the volumetric heat transfer coefficient within the ceramics foam were all conducted. The results indicate that the sample thickness has a significant effect on the volumetric heat transfer coefficient which decreases with the sample thickness. In addition, the local thermal equilibrium phenomenon is verified and its influence on the volumetric heat transfer coefficient discussed. Based on the experimental data, a new correlation is proposed that includes sample thickness, porosity, superficial velocity and fluid properties. This study is crucial to the theory of the convective heat transfer inside the porous media, and can be used to guide the design and optimization of volumetric solar air receivers, compact heat exchangers, heat sinks, heat regenerators, packed bed reactors and so on.

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Forced convection through open cell foams based on homogenization approach: Steady state analysis

Cited by 13 publications

References 34 publications

Experimental Investigations of the Depth Filtration inside Open‐Cell Foam Filters Supported by High‐Resolution Computed Tomography Scanning and Pore‐Scale Numerical Simulations

Experimental Investigations of the Depth Filtration inside Open‐Cell Foam Filters Supported by High‐Resolution Computed Tomography Scanning and Pore‐Scale Numerical Simulations

Numerical and Experimental Study on Convective Heat Transfer Characteristics in Foam Materials

Experimental Study of the Convective Heat Transfer and Local Thermal Equilibrium in Ceramic Foam

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