Vane Rheometer Research Articles

Numerical investigation of the reduction of wall-slip effects for yield stress fluids in a double concentric cylinder rheometer with slotted rotor

Wall-slip effects in a rheometer with double concentric cylinder geometry may lead to significant errors in measurement of the apparent viscosity. Previously, we proposed to use a slotted rotor design to reduce these effects. In this paper, we conduct two as well as three-dimensional computational fluid dynamics (CFD) simulations to determine the differences in rheological measurements of yield stress fluids between the slotted and non-slotted rotor designs. The test fluid and the slip wall boundary of a rotor are characterized in our computational model by the constitutive equation of Zhu et al. [“Non-Newtonian fluids with a yield stress,” J. Non-Newtonian Fluid Mech. 129, 177–181 (2005)] and the wall-slip length method, respectively. The model has been validated against the existing rheological data measured using a vane rheometer. The results of this study indicate that the rheometer equipped with a slotted rotor can measure the fluid properties with enhanced accuracy and less sensitivity to the wall-s...

Hydraulic, physical and rheological characteristics of rain‐triggered lahars at Semeru volcano, Indonesia

AbstractLahars (volcanic debris flows) have been responsible for 40% of all volcanic fatalities over the past century. Mount Semeru (East Java, Indonesia) is a persistently active composite volcano that threatens approximately one million people with its lahars and pyroclastic flows. Despite their regularity, the behaviour and the propagation of these rain‐triggered lahars are poorly understood. In situ samples were taken from lahars in motion at two sites in the Curah Lengkong River, on the southeast flank of Semeru, providing estimates of the particle concentration, grain size spectrum, grain density and composition. This enables us to identify flow sediment from three categories of lahars: (a) hyperconcentrated flow, (b) non‐cohesive, clast‐ and matrix‐supported debris flow, and (c) muddy flood. To understand hyperconcentrated flow sediment transport processes, it is more appropriate to sample the active flows than the post‐event lahar deposits because in situ sampling retains the full spectrum of the grain‐size distribution. Rheometrical tests on materials sampled from moving hyperconcentrated flows were carried out using a laboratory vane rheometer. Despite technical difficulties, results obtained on the <63, <180, and <400 µm fractions of the sampled sediment, suggest a purely frictional behaviour. Importantly, and contrary to previous experiments conducted with monodisperse suspensions, our results do not show any transition towards a viscous behaviour for high shear rates. These data provide important constraints for future physical and numerical modelling of lahar flows. Copyright © 2010 John Wiley & Sons, Ltd.

A numerical study of the flow of Bingham-like fluids in two-dimensional vane and cylinder rheometers using a smoothed particle hydrodynamics (SPH) based method

In this paper, a Lagrangian formulation of the Navier–Stokes equations, based on the smoothed particle hydrodynamics (SPH) approach, was applied to determine how well rheological parameters such as plastic viscosity can be determined from vane rheometer measurements. First, to validate this approach, a Bingham/Papanastasiou constitutive model was implemented into the SPH model and tests comparing simulation results to well established theoretical predictions were conducted. Numerical simulations for the flow of fluids in vane and coaxial cylinder rheometers were then performed. A comparison to experimental data was also made to verify the application of the SPH method in realistic flow geometries. Finally, results are presented from a parametric study of the flow of Bingham fluids with different yield stresses under various applied angular velocities of the outer cylindrical wall in the vane and coaxial cylinder rheometers. The stress, strain rate and velocity profiles, especially in the vicinity of the vane blades, were computed. By comparing the calculated stress and flow fields between the two rheometers, the validity of the assumption that the vane could be approximated as a cylinder for measuring the rheological properties of Bingham fluids at different shear rates was tested.

Vers une réelle rhéométrie adaptée aux bétons frais

ABSTRACT In the first section of this paper, the rheological behaviour of concretes obtained with different rheometers is investigated from a procedure allowing the plot of the flow curve of sheared material. Secondly, the rheological properties of industrial concretes are studied with a high torque vane rheometer. The flow properties of concrete are evaluated and compared, as well as the reproductibility of the making process of concrete.

Vers une réelle rhéométrie adaptée aux bétons frais

ABSTRACT In the first section of this paper, the rheological behaviour of concretes obtained with different rheometers is investigated from a procedure allowing the plot of the flow curve of sheared material. Secondly, the rheological properties of industrial concretes are studied with a high torque vane rheometer. The flow properties of concrete are evaluated and compared, as well as the reproductibility of the making process of concrete.

Analysis of the vane rheometer using 3D finite element simulation

The vane rheometer has been used for more than two decades to characterize various complex materials. The objective of this work is to investigate for the first time the flow hydrodynamics of Newtonian, shear-thinning and yield stress fluids in one such rheometer by means of three-dimensional finite element simulation. The velocity field and stress distributions are predicted using finite element meshes that are much more refined than the two-dimensional meshes of previous studies. The validity of the no-slip boundary condition on the blade surfaces, which is commonly assumed in these previous studies, is assessed by comparing the calculated torque to experimental data in the case of Newtonian, shear-thinning and yield stress fluids. The effect of the power-law index and apparent yield stress on the stress profile near the blades and away from them is investigated and discussed. It is shown, in particular, that the uniform stress assumption at the vane ends is reasonable for power-law fluids with n<0.5 an...

GENERAL PRINCIPLES

Retrogradation and Gel Textural Attributes of Corn Starch Amylose and Amylopectin Fractions. J.P. Mua and D.S. Jackson. Tailoring Texture for the Elderly: Theoretical Aspects and Technological Options. M. Peleg.Shear‐thinning Predictions From Particles Motion Modeling. R.R. Bilodeau and D.W. BousfieldRheology of Suspensions of Weakly Attractive Particles: Approach to Gelation. C.J. Rueb and C.F. ZukowskiCharacterization of Dynamic Viscoelastic Behavior of Wheat Flour Doughs at Different Moisture Content. P. MasiRheological Properties of (l+ 3), (l‐r 4)‐β‐D‐Glucans from Raw, Roasted, and Steamed Oat Groats. D. Zhang, D.C. DoehlertComposition, Thermal Behavior, and Gel Texture of Prime and Tailings Starches from Garbanzo Beans and Peas. Z. CzuchajowskaRheological Properties of (l+ 3), (l‐r 4)‐@‐D‐Glucans from Raw, Roasted, and Steamed Oat Groats. D. Zhang, D.C. DoehlertComposition, Thermal Behavior, and Gel Texture of Prime and Tailings Starches from Garbanzo Beans and Peas. Z. CzuchajowskaPredicting the Electrorheological Behavior of Milk Chocolate. C.R. DaubertAdhesion‐Strength Characteristics of Double‐Layered Agar‐Galactomannan Mixed Gels. 0. Ben‐Zion and Z. NussinovitchPeach Firmness Prediction by Multiple Location Impulse Testing. M.L. Stone, P.R. ArmstrongAcoustic Testing of Avocado for Fruit Ripeness Evaluation. N. GhaliliComparative Study of Viscoelastic Properties Using Virgin Yogurt. G. DimonteMeasurement of Foam Modulus via a Vane Rheometer. X.D. Zhang, D.W. Giles, V.H. Barocas, K. Yasunaga and C.W. MacoskoRheological Phenomena Occurring During the Shearing Flow of Mayonnaise. J.A. Goshawk, D. M. BindingA New Approach to Category Scales of Intensity: I Traditional Versus Rank‐Rating. K.‐0. Kim and M. O'MahonyA Warm‐up Sample Improves Reliability of Responses in Descriptive Analysis. L.E. Plemmons and A.V.A. ResureccionCalcium Chelators and Salt Extracted Myofibrillar Protein Injection into Lean Prerigor Beef Muscle: Effects on Tenderness Indices. J.R. ClausPork Softness Assessed Subjectively and Objectively Using Vacuum‐Induced Changes in Reflectance. H.J. SwatlandFormation of Resistant Starch During Deep‐Fat Frying and Its Role in Modifying Mechanical Properties of Fried Patties Containing Corn, Rice, Wheat, or Potato Starch and Water. R.J. Pinthus, R.P. SinghTextural Quality of Green and White Asparagus. E.A. BrovelliEffects of Harvest Maturity on Banana Quality. S. Laylieam and M. KosittrakunEffect of Principal Ingredients on Rheological Behaviour of Biscuit Dough and on Quality of Biscuits. Z. Maache‐RezzougEffect of Pressure (Crust Formation) on Bread Crumb Grain Development. D'A. Hayman, R.C. HoseneyBread Crumb Grain Development During Baking. D'A. Hayman, R.C. Hoseney and J.M. FaubionFactors Controlling Gas Cell Failure in Bread Dough. D'A. Hayman, K. Sipes, R.C. Hoseney

Yield stress measurements of aqueous foams in the dry limit

This paper reports measurements of yield stress of aqueous foams approaching the dry foam limit using a pendulum device. Traditionally, the vane rheometer has been used to measure the yield stress in liquids that exhibit wall slip. However, using the simple and inexpensive pendulum technique, shear rates many orders of magnitudes lower can be achieved. The pendulum was used to observe the change in yield stress for the foam as the gas fraction and bubble size increased. The local gas fraction in the foam was found by measuring the sonic velocity, and the bubble size was determined photographically. Strong support is found for the existence of a true yield stress in aqueous foams at the dry foam limit. Yield stress results, once scaled by σ/〈R〉, agree well with data from previous studies.

Measurement of foam modulus via a vane rheometer

A vane rheometer was used to measure the modulus of foam systems. Modulus development in a reactive polyurethane foam system was captured using a commercial stress-controlled rheometer with a four-blade vane geometry test fixture. The results were compared to those from a temperature programmed flooded parallel plate method. The vane geometry method was shown to be a convenient and accurate way to measure the physical gelation time of the reactive foaming system, without the complexity of the temperature-program method. Shaving cream was used as a calibration material to show the validity of the vane method for foam modulus measurements. For open cell foams, the error in the vane method increases due to the additional compressibility of the foam. The nature and magnitude of this error was analyzed via numerical simulation.

The yield surface of viscoelastic and plastic fluids in a vane viscometer

Vane viscometers are often used to investigate the low shear rate properties of plastic fluids. The shear stress is determined by assuming that the material is held in the space between the vane blades so that it behaves like a rigid cylinder. Experimental evidence supports this assumption and the aim of the present study is to model numerically the yield process in a vane rheometer using viscoelastic and plastic fluids. The finite element method has been used to model the behavior of Herschel-Bulkley (Bingham), Casson and viscoelastic (Maxwell type) fluids. The penalty function approach for the pressure approximation and a rotating reference frame are used together with fine meshes containing more than 1300 elements. The results show that for Herschel-Bulkley (Bingham), and Casson fluids a rotating rigid cylinder of fluid is trapped inside the periphery of the vane, the shear stress is uniformly distributed over the surface of the cylinder. Finally a modified second order fluid is used to simulate the viscoelastic behaviour, anticipated to be an intermediate between the elastic deformation and the plastic flow, to provide a more realistic simulation of the yield process about a vane. In this case, contrast with the concentration of the elastic strain rate at the blade tips, a nearly uniform distribution of the plastic shear rate is still found. This implies that the plastic shear always distributes uniformly during the entire yielding process. Evidently the assumption of uniform shear on a rotating cylinder of material occluded in the blades of a vane is a valid and useful model for many types of fluid possessing a yield stress.

The use of the vane to measure the shear modulus of linear elastic solids

The vane rheometer may be used to obtain an estimate of the shear modulus G of a gelled suspension. Complex variable techniques are used to determine the torque required to turn a two-bladed vane (i.e. a single plate) of diameter 2 a through an angle θ when immersed in a linear elastic material with shear modulus G and Poisson's ratio σ. The torque per unit length is π a 2Gθ(1 + k −1), where k = 3 – 4σ. When σ = 1 2 (a reasonable approximation when studying weak gels) the shear stress τ xy over the surface of the vane is zero, and there is no tendency for slip to occur at the walls of the vane. The more general case of a two-bladed vane in the form of an ellipse is studied, with either a no-slip boundary condition, or a stress-free (slip) boundary condition. This latter case is resolved by representing the complex deformation potentials as infinite series of exponentials. These series are truncated, and the coefficients of each term are determined numerically. Boundary element methods are then used to compute the torque required to turn finite vanes, of length l = l̂a, in a fluid of viscosity μ, at low Reynolds numbers. There is a direct analogy between the governing equations for low Reynolds number flow and the equations governing linear elastic or viscoelastic deformation when σ = 1 2 , with G replaced by μ and θ by the vane's angular velocity Ω. A no-slip boundary condition is assumed over the surface of the vane. The torque is found to be M = 2π a 3μΩ( l̂ + 0.66) for the two-bladed vane, and M = 2π a 3μΩ(1.5 l̂ + 1.20) for a four-bladed vane, when l̂ ⩾ 3. Numerical results on vanes with 3, 6 and 8 blades indicate that the torque per unit length on an n-bladed vane of infinite length is 2π a 2μΩ(2 - 2 n −1). These results were tested experimentally, and good agreement was found between theory and experiment.

Experiments made at the Mare Island Navy-Yard, California, with different screws applied to the united states steam launch no. 4, to ascertain their relative propelling efficiency

The vane rheometer may be used to obtain an estimate of the shear modulus G of a gelled suspension. Complex variable techniques are used to determine the torque required to turn a two-bladed vane (i.e. a single plate) of diameter 2a through an angle θ when immersed in a linear elastic material with shear modulus G and Poisson's ratio σ. The torque per unit length is πa2Gθ(1 + k−1), where k = 3 – 4σ. When σ = 12 (a reasonable approximation when studying weak gels) the shear stress τxy over the surface of the vane is zero, and there is no tendency for slip to occur at the walls of the vane. The more general case of a two-bladed vane in the form of an ellipse is studied, with either a no-slip boundary condition, or a stress-free (slip) boundary condition. This latter case is resolved by representing the complex deformation potentials as infinite series of exponentials. These series are truncated, and the coefficients of each term are determined numerically. Boundary element methods are then used to compute the torque required to turn finite vanes, of length l = l̂a, in a fluid of viscosity μ, at low Reynolds numbers. There is a direct analogy between the governing equations for low Reynolds number flow and the equations governing linear elastic or viscoelastic deformation when σ = 12, with G replaced by μ and θ by the vane's angular velocity Ω. A no-slip boundary condition is assumed over the surface of the vane. The torque is found to be M = 2πa3μΩ(l̂ + 0.66) for the two-bladed vane, and M = 2πa3μΩ(1.5l̂ + 1.20) for a four-bladed vane, when l̂ ⩾ 3. Numerical results on vanes with 3, 6 and 8 blades indicate that the torque per unit length on an n-bladed vane of infinite length is 2πa2μΩ(2 - 2n−1). These results were tested experimentally, and good agreement was found between theory and experiment.