Transparent model concrete with tunable rheology for investigating flow and particle-migration during transport in pipes

Auernhammer, Günter K.; Fataei, Shirin; Haustein, M.; Patel, Himanshu P.; Schwarze, Rüdiger; Secrieru, Egor; Mechtcherine, Viktor

doi:10.1016/j.matdes.2020.108673

Cited by 17 publications

(3 citation statements)

References 19 publications

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“…The material is refractive index matched with Thiodiethanol, and was designed to behave similar to concrete. Details can be found in Auernhammer et al (2020). The transparency allows the material to be examined during flow using the Particle Image Velocimetry (PIV) method.…”

Section: Description Of the Benchmark Problemmentioning

confidence: 99%

Benchmark Simulations of Dense Suspensions Flow Using Computational Fluid Dynamics

et al. 2022

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The modeling of fresh concrete flow is still very challenging. Nevertheless, it is of highest relevance to simulate these industrially important materials with sufficient accuracy. Often, fresh concrete is assumed to show a Bingham-behavior. In numerical simulations, regularization must be used to prevent singularities. Two different regularization models, namely the 1) Bi-viscous, and 2) Bingham-Papanastasiou are investigated. Those models can be applied to complex flows with common simulation methods, such as the Finite Volume Method (FVM), Finite Element Method (FEM) and Smoothed Particle Hydrodynamics (SPH). Within the scope of this investigation, two common software packages from the field of FVM, namely Ansys Fluent and OpenFOAM, COMSOL Multiphysics (COMSOL) from FEM side, and HOOMD-blue.sph from the field of SPH are used to model a reference experiment and to evaluate the modeling quality. According to the results, a good agreement of data with respect to the velocity profiles for all software packages is achieved, but on the other side there are remarkable difficulties in the viscosity calculation especially in the shear- to plug-flow transition zone. Also, a minor influence of the regularization model on the velocity profile is observed.

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Section: Description Of the Benchmark Problemmentioning

confidence: 99%

Benchmark Simulations of Dense Suspensions Flow Using Computational Fluid Dynamics

et al. 2022

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“…The experimental chamber walls are made of transparent acrylic plastic allowing for 360-degree observation of the experiment (Figure 3). To document the deformation within the chamber we take advantage of the almost identical light refraction indices of the experimental materials and the experimental chamber (Budwig, 1994;Byron and Variano, 2013;Klein et al, 2013; Auernhammer et al, 2020;Parker and Merati, 1996). This makes any mixture of these materials indistinguishable in natural light.…”

Section: Observation Of Internal Deformationmentioning

confidence: 99%

New ring shear deformation apparatus for three-dimensional multiphase experiments: First results

McLafferty

Bix²,

Bogatz³

et al. 2022

Preprint

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Abstract. Multiphase deformation, where a solid and fluid phase deform simultaneously, play a crucial role in a variety of geological hazards, such as landslides, glacial slip, and the transition from earthquakes to slow slip. In all these examples a continuous, viscous or fluid-like phase is mixed with a granular or brittle phase where both phases deform simultaneously when stressed. Understanding the interaction between the phases and how they will impact deformation dynamics is essential to improve hazard assessments for a wide variety of geo-hazards. Here, we present the design and first experimental results from a ring shear deformation apparatus capable of deforming multiple phases simultaneously. The experimental design allows for three dimensional observations during deformation in addition to unlimited shear strain, controllable normal force, and a variety of boundary conditions. To impose shear deformation, either the experimental chamber or lid rotate around its central axis while the other remains stationary. Normal and pulling force data are collected with force gauges located on the lid of the apparatus and between the pulling motor and the experimental chamber. Experimental materials are chosen to match the light refraction index of the experimental chamber, such that 3D observations can be made throughout the experiment with the help of a laser light sheet. We present experimental results where we deform hydropolymer orbs and cubes (brittle phase) and Carbopol® hydropolymer gel (fluid phase). Preliminary results show variability in force measurements and deformation styles between solid and fluid end member experiments. The ratio of solids to fluids and their relative competencies in multiphase experiments control deformation dynamics, which range from stick-slip to creep. The presented experimental strategy has the potential to shed light on multi-phase processes associated with multiple geo-hazards.

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“…Additional additives are used to match the refractive index of all constituents. Details of the model concrete and its preparation will be published elsewhere [23].…”

Section: Model Concretementioning

confidence: 99%

Experimental Investigation of the Pumping of a Model-Concrete through Pipes

2020

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Many practical aspects of processing fresh concrete depend on its rheology, such as the pumping of the material. It is known that a lubricating layer is formed in the process, which significantly reduces the pumping pressure. However, these phenomena can hardly be considered in the usual rheological measurements. A main problem is the optical inaccessibility of the material, which prevents estimations about, e.g., the thickness of the plug flow or particle migration. In this paper, the pneumatic pumping of a transparent model concrete is performed by means of a test plant. The flow profile over the entire pipe cross-section is resolved in time and space via Particle Image Velocimetry (PIV) measurements. This allows the comparison with the analytical flow profile from rheological measurements of the material using the Buckingham–Reiner equation. A reduction of the pressure loss to around 60% induced through segregation of the material is found. These measurements reflect the rheology of the material under realistic pumping conditions including particle migration. This makes it possible for the first time to observe a transparent material with concrete-like rheology under pulsating pumping conditions and to compare the true and calculated time-resolved pressure loss.

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Transparent model concrete with tunable rheology for investigating flow and particle-migration during transport in pipes

Cited by 17 publications

References 19 publications

Benchmark Simulations of Dense Suspensions Flow Using Computational Fluid Dynamics

Benchmark Simulations of Dense Suspensions Flow Using Computational Fluid Dynamics

New ring shear deformation apparatus for three-dimensional multiphase experiments: First results

Experimental Investigation of the Pumping of a Model-Concrete through Pipes

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