Author
P.M. Heertjes
Bio: P.M. Heertjes is an academic researcher from Delft University of Technology. The author has contributed to research in topics: Heat transfer & Filtration. The author has an hindex of 14, co-authored 32 publications receiving 891 citations.
Papers
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TL;DR: In this paper, the porosity, the tortuosity and the constrictivity of macroporous media were analyzed in terms of the effective bulk diffusion coefficient and the diffusion coefficient in the absence of the porous medium.
414 citations
TL;DR: In this paper, the elasticity modulus of a fluidized bed has been calculated from a drag force-interparticle distance relation, and a satisfactory criterion for the transition between homogeneous and heterogeneous fluidization has been obtained.
100 citations
TL;DR: In this paper, three aspects of these vibrations have been analyzed: the frequency, the critical bed height and the damping, which is the ratio of the fluid-to-solids-density.
96 citations
TL;DR: Capillary rise experiments have been performed with homogeneous packings of coarse rotund particles, yielding a capillary rise at equilibrium of the order of 10 cm as discussed by the authors, where water, toluene and other organic liquids have been used as the wetting liquid, and glass beads, polystyrene beads, and sand to make the packings.
45 citations
TL;DR: In this paper, simultaneous heat and mass transfer in laminar free convection at a vertical plate has been measured in the liquid phase, where an electrochemical method has been used for the mass transfer and the heat transfer was measured by differential thermal analysis.
25 citations
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TL;DR: The behavior of solids fluidized by gases falls into four clearly recognizable groups, characterized by density difference (ϱs −ϱf) and mean particle size as discussed by the authors, and a numerical criterion which distinguishes between groups A and B has been devised and agrees well with published data.
3,007 citations
TL;DR: In this article, the components of RFBs with a focus on understanding the underlying physical processes are examined and various transport and kinetic phenomena are discussed along with the most common redox couples.
Abstract: Redox flow batteries (RFBs) are enjoying a renaissance due to their ability to store large amounts of electrical energy relatively cheaply and efficiently. In this review, we examine the components of RFBs with a focus on understanding the underlying physical processes. The various transport and kinetic phenomena are discussed along with the most common redox couples.
1,661 citations
TL;DR: In this paper, the authors analyzed the accessibility of the rock matrix to radio-nuclides and showed that the diffusion of the nuclides into the rock matrices and their sorption onto the surfaces of the microfissures are the main mechanisms retarding migration from a repository.
Abstract: This paper discusses migration of radionuclides in the bedrock surrounding a repository. Currently available models use either a surface reaction or a bulk reaction concept to describe the retardation of migrating nuclides. The first model assumes that the nuclide reacts only with the surface of the fissures. This implies that the rock matrix is not utilized as a sink. The other model implies that the whole bulk of the rock is accessible to the nuclides. The paper analyzes the accessibility of the rock matrix to the radio-nuclides. The transport mechanisms are shown to be flow of water and nuclides in the fissures and transport of nuclides from the water in the fissures into water in the microfissures of the rock by pore diffusion. The diffusion of the nuclides into the rock matrix and their sorption onto the surfaces of the microfissures are the main mechanisms retarding migration from a repository. The diffusivity of the nuclide may be as important as its sorption equilibrium constant. Diffusivities in the pores and microfissures in such dense rocks as granite under confining pressure of hundreds of bars can be expected to be 6–20% of the diffusivity in water. These data are obtained from electrical resistivity measurements of saltwater-filled granites. Porosity of such granites varies from 0.4 to 0.9%. The apparent diffusivities in the granites will then vary between 0.25 · 10−12/Kdρp and 10 · 10−12/Kdρp m2/s, where Kdρp is the volume equilibrium constant. This varies from the porosity of the rock for nonsorbing species to up to and over 104. For a 100-year contact time a nonsorbing nuclide can be expected to penetrate tens of meters of the rock matrix and a strongly sorbing nuclide with Kdρp larger than 104 will penetrate a few millimeters. The diffusion into the rock matrix can enhance the retardation by many orders of magnitude as compared to retardation by surface reaction in fissures only. The retardation may, on the other hand, be many orders of magnitude smaller than the maximum value that could be obtained if all the rock matrix were accessible. This depends very much on the fissure widths and spacings.
810 citations
TL;DR: In this article, the authors show that tortuosity is accurately correlated to readily measured porosity values, φ, through the simple relation: θ 2 = 1 − l n ( φ 2 ).
654 citations
TL;DR: A review of the recently reported moisture diffusivity experimental data in food materials is presented in this article, where values are classified and analysed statistically to reveal the influences of temperature and moisture content.
Abstract: A review of the recently reported moisture diffusivity experimental data in food materials is presented in this work Values are classified and analysed statistically to reveal the influences of temperature and moisture content Empirical models relating moisture diffusivity with the above variables, along with relevant graphs for various materials, are included Other factors affecting moisture diffusivity prediction are also discussed
594 citations