Numerical Simulation of the Flow Behavior of Newtonian Fluids in a Wide Gap Rheometer by CFD

Pirharati, Mahmoud Eslami; Ivanov, Dimitri A.; Krauss, Hans-W.; Schilde, Carsten; Lowke, Dirk

doi:10.1007/978-3-030-22566-7_68

Cited by 5 publications

(9 citation statements)

References 4 publications

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“…As presented in Fig. 3a, the rheologically tested material can show inhomogeneous flow behaviour, especially near the edges of vane blades [36,37]. Moreover, the case of partially sheared flow, i.e., plug flow, in a wide-gap coaxial rheometer and material flow behaviour near the vane geometry from magnetic resonance imaging (MRI) technique are both demonstrated in [36].…”

Section: Reiner-riwlin (Rr) Approach For Wide Gap Coaxial Measurementmentioning

confidence: 90%

“…According to [37] about 95% of total torque is applied to the lateral surface in the case of the vane-incup setup. However, the non-linear torque contribution of different vertical segments of the vane probe has to be respected in addition [37].…”

Section: Reiner-riwlin (Rr) Approach For Wide Gap Coaxial Measurementmentioning

confidence: 99%

“…Top view of a coaxial vane-in-cup system in the case of plug flow; b CFD simulation of material flow at the middle heigt of vane geometry (horizontal section) for a Newtonian fluid (silicone oil AK 5000); taken from[37] Flow curve shown as boxplot layout of the reference measurements on ultrasound gel using a cone-plate measurement device (CP-1, see Tab. 2).…”

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confidence: 99%

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Interlaboratory study on rheological properties of cement pastes and reference substances: comparability of measurements performed with different rheometers and measurement geometries

et al. 2020

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This paper presents the results of an interlaboratory study of the rheological properties of cement paste and ultrasound gel as reference substance. The goal was to quantify the comparability and reproducibility of measurements of the Bingham parameters yield stress and plastic viscosity when measured on one specific paste composition and one particular ultrasound gel in different laboratories using

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Section: Reiner-riwlin (Rr) Approach For Wide Gap Coaxial Measurementmentioning

confidence: 90%

Section: Reiner-riwlin (Rr) Approach For Wide Gap Coaxial Measurementmentioning

confidence: 99%

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Interlaboratory study on rheological properties of cement pastes and reference substances: comparability of measurements performed with different rheometers and measurement geometries

et al. 2020

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“…the last 2 s of each step. The shear stress was calculated from the torque value following geometric basics according to the Reiner-Riwlin equation [39,54]. The yield stress τ 0,B for each flow curve was calculated following the Bingham regression for the steady state between 20 rpm and 60 rpm.…”

Section: Rheological Measurementsmentioning

confidence: 99%

“…The vertical section exhibits an inner width of 50 mm and an inner depth of 45 mm, with a total height of 540 mm. Reiner-Riwlin equation [39,54]. The yield stress , for each flow curve was calculated following the Bingham regression for the steady state between 20 rpm and 60 rpm.…”

Section: Empirical Stoppage Testsmentioning

confidence: 99%

L-Box Form Filling of Thixotropic Cementitious Paste and Mortar

et al. 2020

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Rheological properties of cementitious pastes and mortar affect the casting, placement, and setting properties of fresh concrete. Fundamental rheological knowledge thus helps in predicting concrete flowability and workability. Empirical equations correlate actual rheological parameters based on physical material characteristics to workability tests. Still, these equations generally only take the dynamic yield stress of the material into account. This is not sufficient for thixotropic cementitious pastes or mortars, which possess structural buildup at rest. Workability predictions regarding the flow of concrete are thus more complicated with thixotropic materials. During form-filling in L-shaped formworks, the flow velocity of concrete slows down, wherefore rheological parameters change with time. At initial fast flow, high shear rates without structural buildup can be assumed. Dynamic yield stress and a steady state viscosity thus are proper parameters for empirical equations describing concrete flowability. During low shear rates, partial structural buildup takes place. Viscosity and yield stress increase due to agglomeration and affect the flowability of concrete tremendously. Rheological parameters of various cementitious pastes and mortars varying in their solid volume fraction and flowability were investigated in a vane-in-cup rheometer. The workability of the same mixtures was investigated by measuring the flow length in an L-shaped formwork. The effect of yield stress, viscosity, and thixotropic structural buildup on flow length was investigated. Subsequently correlations and discrepancies between flowability parameters and workability equations were analyzed.

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Mastering the rheology of fresh concrete: New knowledge from a DFG priority program SPP 2005

Mechtcherine

2023

ce papers

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The processing of cement‐based building materials represents the technological core in the construction and maintenance of structures. However, a scientific framework for mastering rheology‐based processes is still in an early stage of its development. The reason for this is the extremely high complexity of cementitious systems. This complexity includes the high chemical reactivity of mineral binders, the complex multi‐phase nature of fresh concrete or mortar, and a wide range of deformation rates during various technological processes, which result in extremely high demands for characterization and simulation methods. The goal of the DFG Priority Program SPP 2005 “Opus Fluidum Futurum – Rheology of reactive, multiscale, multiphase construction materials” is to ascertain and describe the scientific fundamentals for understanding and, subsequently, designing rheology‐based construction processes as well as for developing innovative, sustainable building materials and associated pioneering processing technologies. The article at hand presents the purpose and the structure of the collaborative research as well as the achievements of the priority program. Furthermore, it offers some insights into ongoing and planned research.

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Numerical Simulation of the Flow Behavior of Newtonian Fluids in a Wide Gap Rheometer by CFD

Cited by 5 publications

References 4 publications

Interlaboratory study on rheological properties of cement pastes and reference substances: comparability of measurements performed with different rheometers and measurement geometries

Interlaboratory study on rheological properties of cement pastes and reference substances: comparability of measurements performed with different rheometers and measurement geometries

L-Box Form Filling of Thixotropic Cementitious Paste and Mortar

Mastering the rheology of fresh concrete: New knowledge from a DFG priority program SPP 2005

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