Measurement and simplified numerical prediction of effective thermal conductivity of open-cell ceramic foams at high temperature

Mendes, Miguel A.A.; Goetze, Pitt; Talukdar, Prabal; Werzner, Eric; Demuth, Cornelius; Rößger, Philip; Wulf, Rhena; Groß, Ulrich; Trimis, D.; Ray, Subhashis

doi:10.1016/j.ijheatmasstransfer.2016.06.022

Cited by 38 publications

(12 citation statements)

References 37 publications

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“…its porosity and pore size. A further problem with these materials is that the repeatability of the morphology is not constant, even when the same manufacturing conditions are employed, resulting in an inherent scatter in the material properties unless very large samples are tested [5,11,12].…”

Section: Introductionmentioning

confidence: 99%

“…Although it can be demonstrated that the pore size has little direct influence on ETC, the pore size will influence the foam fabrication process, and by establishing limits on what foams may actually be produced (there are usually upper and lower size limits). To this extent, pore size can affect the ETC [12,18]. The pore size itself is additionally not well defined as measures including both average pore diameters and Pores Per Inch (PPI) are presented in the literature.…”

Section: Introductionmentioning

confidence: 99%

“…However, these general approaches have not been successful in predicting the ETC of most open celled metal sponges with accuracy. Strategies that go beyond simplified unit cell structures have been explored, for example, by analysing the real foam structure obtained from 3D computed tomography [12] to observe its effects on the ETC. This can support the development of more accurate generic correlations [10,12,18], but is limited by the small volumes of foams that can be investigated in this way.…”

Section: Introductionmentioning

confidence: 99%

“…Strategies that go beyond simplified unit cell structures have been explored, for example, by analysing the real foam structure obtained from 3D computed tomography [12] to observe its effects on the ETC. This can support the development of more accurate generic correlations [10,12,18], but is limited by the small volumes of foams that can be investigated in this way. A review of the wide range of theoretical and empirical approaches for porous metals found that each model defines a specific morphology and is hence of limited applicability to other types [11,12,18].…”

Section: Introductionmentioning

confidence: 99%

“…The most common type of transient measurement is the Transient Plane Source technique (TPS) [25,26], where a single element acts as both temperature sensor and heat source . It has been widely used to measure the ETC of porous materials [6,12,23]. The TPS element is positioned between two samples with similar characteristics and measures the instantaneous temperature gradient with time [6,25,26].…”

Section: Introductionmentioning

confidence: 99%

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The effective thermal conductivity of open cell replicated aluminium metal sponges

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Goodall

et al. 2017

International Journal of Heat and Mass Transfer

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The effective thermal conductivity of open cell replicated aluminium metal sponges

Abuserwal

Luna

Goodall

et al. 2017

International Journal of Heat and Mass Transfer

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Simulation of Fluid Flow, Heat Transfer and Particle Transport Inside Open-Cell Foam Filters for Metal Melt Filtration

Werzner,

Mendes,

Demuth

et al. 2024

Springer Series in Materials Science

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In order to develop improved filters for metal melt filtration, different physical phenomena that take place during depth filtration of liquid metals need to be well understood. Due to the difficult accessibility of the process, the harsh process conditions and the randomness of the typically employed ceramic foam filters, representative experimental investigations are extremely difficult to perform and often provide only integral quantities or selective information. This chapter presents a numerical model for simulating the depth filtration of liquid metal at the pore-scale, i.e., fully resolving the complex filter geometry, which can also accurately handle the curved filter walls. In the model, the velocity and pressure distribution of the melt flow is obtained by the lattice-Boltzmann method and the temperature field is calculated using the finite volume method, while the transport and filtration of the inclusions are predicted by solving the equation of motion for particles in a Lagrangian reference frame. In order to obtain a consistent representation of the curved filter walls for both particle transport and fluid flow, the Euclidean distance field of the filter structures is employed. By comprehensive parametric studies, the sensitivity of the filtration process with respect to various geometric parameters and process conditions is investigated. Therefore, geometries of conventionally manufactured filters, acquired from 3D μCT scanning, as well as computer-generated filter structures are considered. Their performance is assessed by evaluating various effective properties, such as the viscous and inertial permeability and the filtration coefficient. The numerical predictions allow to draw conclusions with respect to the dominant physical mechanisms and are compared with those from simplified physical models, which are shown to be sufficiently accurate for the pre-screening of filters. On the basis of the detailed results, suggestions for improved filter geometries are made, depending on the considered filtration process. Further, simplified models for the prediction of the effective thermal conductivity of open-cell foams in presence and absence of radiation are presented and validated using the detailed numerical predictions.

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Characterization of Heat Transport and Diffusion Processes During Metal Melt Filtration

Heisig,

Markuske,

Wulf

et al. 2024

Springer Series in Materials Science

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This chapter contains a summary of thermodynamic investigations of ceramic filters, metal melts and their interaction, which can serve as a basis for the optimization of the filters as well as the casting and metal melt filtration process. First, the thermophysical properties of two different filter base materials are briefly discussed. Subsequently, after demonstrating measurement conditions and parameters, the effective thermal conductivities of filters with varying pore size, porosity and material measured by the Transient-Plane-Source method at temperatures up to 700 °C are presented. The experimental determination of radiative properties of the filters using a Fourier-transform infrared spectrometer with an external integrating sphere was compared to simple predictive methods. Finally, after performing experiments with air, a measurement section was created and further developed to determine the volumetric heat transfer coefficient during metal melt filtration. The first results obtained with aluminum melt are presented.In addition to the knowledge of heat transport processes, the understanding of the sorption and diffusion behavior of various gases in metal melts is important. Therefore, a thermogravimetric apparatus, which enables the direct determination of the mass changes caused by (ab-)sorption using a high-precision magnetic suspension balance, was modified especially for this measurement task.

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Measurement and simplified numerical prediction of effective thermal conductivity of open-cell ceramic foams at high temperature

Cited by 38 publications

References 37 publications

The effective thermal conductivity of open cell replicated aluminium metal sponges

The effective thermal conductivity of open cell replicated aluminium metal sponges

Simulation of Fluid Flow, Heat Transfer and Particle Transport Inside Open-Cell Foam Filters for Metal Melt Filtration

Characterization of Heat Transport and Diffusion Processes During Metal Melt Filtration

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