Systems and methods for determining the yield stress of a non-Newtonian fluid in real time are provided. A pressure loss and/or liquid rise technique, an ultrasonic technique, and/or a penetrometer technique can be used to determine the yield stress of a non-Newtonian fluid. The ultrasonic technique can include a longitudinal wave approach and/or a shear wave approach. The methods and systems are non-invasive and only require slight modifications to the piping containing the non-Newtonian fluid in order to measure the yield stress.

A time-varying detecting device and method for concrete rheological parameters, in which the double-covered cylinder has top and bottom covers (11, 12), both of which can be freely opened, is configured to contain a concrete sample, and a lifting frame includes a pair of vertical supports (21) extending in parallel with each other. The double-covered cylindrical container is held between the pair of vertical supports (21) by means of connecting members (30) in such a manner that it can be flipped 180° about a straight line along which the connecting members (30) extend under the action of an external force. To perform a test, the top cover (11) is opened and a concrete mix is filled in, followed by detecting initial rheological parameters. The top cover (11) is closed, and the concrete mix is left for a predetermined period of time. The double-covered cylindrical container is lifted to a predetermined height by raising the connecting members (30), flipped 180° and lowered back onto the floor. The bottom cover (12) is opened, and the concrete mix is re-mixed and homogenized, followed by finally detecting the time-varying rheological parameters of the concrete mix.

The invention relates to a method for determining the intrinsic viscosity [η] of an aqueous polymer solution at a temperature T, wherein the aqueous polymer solution comprises at least one acrylamide-based polymer in an aqueous solvent, the aqueous solvent having a salinity of from 6 to 250 g/L, the method comprising the steps of: —providing a single universal relation R.sub.1 between (i), the product of polymer concentration and intrinsic viscosity C.Math.[η], and (ii) specific viscosity at zero shear rate η.sub.sp; —performing a measurement of the dynamic viscosity of the aqueous polymer solution at one polymer concentration C.sub.1, at temperature T and at various shear rates; —determining from said measurement the zero-shear viscosity η.sub.0 of the aqueous polymer solution at polymer concentration C.sub.1 and at temperature T; —calculating the specific viscosity at zero shear rate of the aqueous polymer solution at polymer concentration C and at temperature T as η.sub.sp=(η.sub.0−η.sub.s)/η.sub.s, where η.sub.s is the zero-shear viscosity of the aqueous solvent; —estimating the intrinsic viscosity [η] of the aqueous polymer solution at temperature T by applying the universal relation R.sub.1 to the calculated specific viscosity at zero shear rate η.sub.sp and polymer concentration C.sub.1.

Apparatuses and methods are disclosed for the analysing of non-Newtonian fluids and determining parameters to characterise the relationship between shear stresses and shear rates, i.e. the parameters of one or more rheological models of viscosity. A plurality of viscosity measurements are made in a fluid using one or more vibratory transducers operating at a plurality of frequencies. Parameters for the fluid are determined based on the measured viscosity values and the frequencies of vibration at which the viscosity measurements were obtained.

The present disclosure is directed to rheometric fixtures for making rheological measurements of yield stress fluids. In some embodiments, the fixture can be an improvement of a typical vane by having the ability to create a more homogeneous shear profile in a test material, e.g., a yield stress fluid. These vane fixtures having fractal-like cross-sectional structures enable robust rheological measurements of the properties of yield stress fluids due to several outer contact edges that lead to increased kinematic homogeneity at the point of yielding and beyond. The branching structure of the fractal-like fixtures can alter the shape of a wetted perimeter of the fixture while minimizing an area thereof to allow the fixture to be inserted into fluids with less disturbance. In some embodiments, a cup with a ribbed inner surface can be used to hold the sample fluid and disassembles for ease of cleaning following completion of the measurement.

Techniques for determining rheological properties of a fluid include actuating a resonator disposed in a volume that contains a fluid sample to operate the resonator in the fluid sample at a predetermined actuation scheme; measuring at least one characteristic of the resonator based on the operation of the resonator in the fluid sample; comparing the at least one measured characteristic to a rheological model that associates characteristics of the fluid sample to one or more rheological properties; and based on the comparison, determining one or more rheological properties of the fluid sample.

A model of the viscoplastic boundary layer of a yield stress fluid is described and, based on which, there is provided a method of estimating the yield stress of a flowing yield stress fluid using one or more vibratory transducers having a vibratory surface in contact with the yield stress fluid, the method comprising: vibrating a vibratory surface of a vibratory transducer to transmit a wave from a vibrating surface into a viscoplastic boundary layer of the flowing yield stress fluid, the wave propagating a distance into the viscoplastic boundary layer; making, using the vibrations of the vibratory transducer, one or more measurements of the degree of damping of vibration; and estimating the yield stress of the flowing yield stress fluid based on the one or more measurements of the degree of damping of vibration. There are disclosed single-frequency, dual-frequency and triple-frequency modes of operation.

In some examples, a fluid analysis device (FAD) comprises a fluid chamber comprising an agitator and a shear stress sensor exposed to a surface within the fluid chamber.

A model of the viscoplastic boundary layer of a yield stress fluid is described and, based on which, there is provided a method comprises the steps of: vibrating a vibratory transducer at resonance at a first resonant mode in a yield stress fluid and making a first measurement of the resonant frequency; providing a vibration to liquefy at least a portion of the yield stress fluid around the one or more vibratory transducers; while said portion of the yield stress material is liquefied, vibrating a vibratory transducer at resonance at the first resonant mode in the yield stress fluid and making a second measurement of the resonant frequency; and estimating the yield stress of the yield stress fluid based on the first and second measurements. The vibration to liquefy yield stress fluid around the one or more transducers may be provided by the making of the second measurement at an increased amplitude of vibration relative to the first measurement.

The present invention relates to a method for predicting the break-up possibility of a synthetic resin filament in a melt blowing process from the rheological properties of the synthetic resin. According to the present invention, a method that is capable of predicting the break-up possibility of the synthetic resin filament in the melt blowing process for preparing a filament using the synthetic resin in advance, through the measurement of the rheological properties of the synthetic resin, is provided.