Continuous Measurement Of Viscosity Research Articles

Detailed Analysis of the Effects of Viscosity Measurement Errors Caused by Heat Transfer during Continuous Viscosity Measurements under Various Temperature Changes and the Proposed Solution of a Non-Dimensional Parameter Called the Akpek Number

It is extremely important to gather the viscosity behavior of fluids accurately for industries and academia. There is no better method than viscosity measurement to detect changes in the specific characteristics of the materials. However, viscosity measurement is indeed a very sensitive process. In nature, fluids are involved in widely various containers, and they are affected by serious temperature deviations. It is a necessity for viscometers to have the capability to obtain accurate data from all types of containers of fluids even in serious temperature variations in order to understand the natural phenomena inside the fluids. Conventional viscometers mainly neglect the effect of sudden temperature deviations inside the fluids, or they need to use very expensive water bath systems that stabilize the temperature around the test fluids, which is not feasible at all. In this research, the effects of non-uniform temperature fields are analysed detailly to confirm that even in extremely limited amounts, serious viscosity and temperature deviations may occur. Experiments were performed in two parts. The first part was conducted using several thermocouples with different test fluids to find out the effects of thermal conduction and convection. For the second part, particle image velocimetry (PIV) was utilized to comprehend the flow movement within the test fluids. It was shown that even for small volumes and even in very controlled environments, an almost 35% viscosity measurement error (VME) occurs. Finally, as a solution to this problem, a new non-dimensional parameter called the Akpek number was proposed. The Akpek number enables the estimation of VMEs in any possible case. VME is a very crucial obstacle that has urgency to be illuminated by researchers and scientists to improve fluid characteristics. The main goal of this research is to illuminate the importance of this problem and offer a potential solution. The final results are supported by experimental data and numerical simulations using OpenFOAM.

Development of an Integrated System for the Automatic Viscosity Correction of a Ceramic Slurry for the Investment Casting Process

Background: Starting from a wax model of the mold, which is later discarded, investment casting is used to make almost finished metal cast parts. The term "investment casting" is derived from the use of a ceramic liquid mixture (slurry), in which the model is repeatedly immersed (invested) to form, layer by layer, the shell which has to be filled with molten metal. The liquid of the slurry tends to evaporate so that the viscosity of the former increases and a correction is needed. Objective: The study aimed to investigate the simplest way to measure slurry viscosity and automatically correct it. Methods: Numerical and experimental tests have been implemented to correctly assess the proposed method. An integrated system for the automatic correction of slurry viscosity is realised which comprises: a reservoir of slurry including means for mixing it; a transducer which continuously measures the slurry viscosity; a pump that gradually feeds the diluent into the slurry to keep its viscosity constant; and a device, governed by the continuous viscosity measurement, that operates the pump. Results: It has been proved that the developed system is able to integrate the slurry viscosity continuous measurement with gradual addition of diluent into the slurry, so as to have a fully automated operation that can make corrections, whenever necessary, on the basis of the transducer output. Conclusion: The developed system works properly by keeping the slurry viscosity within a fixed range. A patent has been recently deposited to protect the integrated system for the automatic correction of slurry viscosity.

A Rapid Capillary-Pressure Driven Micro-Channel to Demonstrate Newtonian Fluid Behavior of Zebrafish Blood at High Shear Rates

Blood viscosity provides the rheological basis to elucidate shear stress underlying developmental cardiac mechanics and physiology. Zebrafish is a high throughput model for developmental biology, forward-genetics, and drug discovery. The micro-scale posed an experimental challenge to measure blood viscosity. To address this challenge, a microfluidic viscometer driven by surface tension was developed to reduce the sample volume required (3μL) for rapid (<2 min) and continuous viscosity measurement. By fitting the power-law fluid model to the travel distance of blood through the micro-channel as a function of time and channel configuration, the experimentally acquired blood viscosity was compared with a vacuum-driven capillary viscometer at high shear rates (>500 s−1), at which the power law exponent (n) of zebrafish blood was nearly 1 behaving as a Newtonian fluid. The measured values of whole blood from the micro-channel (4.17cP) and the vacuum method (4.22cP) at 500 s−1 were closely correlated at 27 °C. A calibration curve was established for viscosity as a function of hematocrits to predict a rise and fall in viscosity during embryonic development. Thus, our rapid capillary pressure-driven micro-channel revealed the Newtonian fluid behavior of zebrafish blood at high shear rates and the dynamic viscosity during development.

Effect of non-uniform temperature field in viscosity measurement

In viscosity measurement, temperature control is very important. In this research, the effects of temperature distribution in viscosity measurement are investigated. Vibrational viscometers are preferred in experiments over other types of viscometers due to their low cost, easy to use and effective continuous viscosity measurement capability. This study was conducted in two parts. In the first part, thermal convection phenomenon within the experimental cup is analyzed. The experiments are carried out with three different standard fluids in continuously increasing temperature environment. Experimental outcomes show that when viscosity of the test fluid increases, the non-uniformity of the temperature field grows in the cup and results in viscosity measurement errors. In the second part, thermal conduction phenomenon is investigated. This experiment is repeated several times with different heating speeds in one selected standard fluid to gain a better understanding about the effect of thermal conduction in fluid viscosity. Experimental outcomes show that under some conditions viscosity measurement errors could reach up to 49.6 %. These findings have also been verified by mathematical calculations.

Electromagnetically revolving sphere viscometer

In this paper, we propose a new method of low viscosity measurement, in which the rolling of a probe sphere on the flat solid bottom of a sample cell is driven remotely and the revolution speed of the probe in a sample liquid gives the viscosity measurements. The principle of this method is based on the electromagnetically spinning technique that we developed, and the method is effective especially for viscosity measurements at levels below 100 mPa·s with an accuracy higher than 1%. The probe motion is similar to that in the well-known rolling sphere (ball) method. However, our system enables a steady and continuous measurement of viscosity, which is problematic using the conventional method. We also discuss the limits of the measurable viscosity range common to rolling-sphere-type viscometers by considering the accelerating motion of a probe sphere due to gravity, and we demonstrate the performance of our methods.

A Study on Vibrational Viscometers Considering Temperature Distribution Effect

In viscosity measurement, temperature control is very important. In this study, the effects of temperature distribution on vibrational viscometers are investigated. Vibrational viscometers are preferred over other types of viscometers owing to their low cost, easy to use and efficacious continuous viscosity measurement capability. The study was conducted in two parts. In the first part, the challenge of unequal temperature distribution in vibrational viscometers was analyzed. The heat generated by a heater during continuous viscosity measurement disperses every part of a sample fluid and influences the fluid's viscosity. Therefore, the sample fluid may have inhomogeneous viscosity values because temperature distribution cannot be equal at every point in a fluid. This experiment is repeated several times with different temperature gradients for gaining a better understanding about the effect of unequal temperature distribution on fluid viscosity. Experimental outcomes show that under some conditions, viscosity measurement errors could reach 27.9%. This finding has been verified by mathematical calculations. In the second part of the research, for solving the unequal temperature distribution problem, the use of a magnetic stirrer for mixing up the fluid throughout the viscosity measurement with the aim of achieving homogenous temperature distribution is proposed.

Ultrasound Viscosity Measurements Allow Determination of Gas Volume Fraction in Foamed Gels

AbstractAerated whey protein gels were obtained by gelation of preheated solutions at room temperature by calcium, magnesium and ferrum (II) ions at different pH and protein concentration. The density of aerated and non‐aerated gels was determined by the flotation method. Dynamic viscosity of aerated and non‐aerated gels was measured using an ultrasonic viscometer. Air fraction of obtained aerated gels ranged from 24.5 to 76.8%. There was a linear increase in the product of viscosity and density values with increasing concentration of non‐aerated gels. For aerated gels, the highest values of the product of viscosity and density were noted at 7.5 and 8.0% (w/w). A formula for calculation of the air fraction in aerated gels by ultrasound viscosity measurements was derived. Air fraction values obtained by density measurements correlated with the air fraction values obtained by ultrasound viscosity measurements (R2 = 0.99). Measurements of the product of viscosity and density values by an ultrasound viscometer allow the determination of the air fraction of aerated gels.Practical ApplicationsDifferent methods can be applied to obtain aerated whey protein gels. One common method capitalizes on the gel reversibility. Another common method is based on the gelation of preheated solutions induced at room temperature by salt addition. Foamed gels can be applied in food technology and as matrices for active ingredient release. Ultrasonic viscometers are used for continuous measurement of viscosity under conditions where measurement is difficult and does not influence the sample shape. Viscoelastic properties of the gels can be measured using oscillatory rheometry, but ultrasound viscosity measurements can also characterize the viscosity of the gel samples. Ultrasound viscometers are cheaper than oscillatory rheometers and the measurements are simpler.

Wide-range viscoelastic measurement using resonating sensors

We have developed a specially designed sensor with its associated instrumentation using a so called acoustical near-field technique based on small resonating horns. Contrary to the conventional measuring devices used in the rheology industry, this sensor enables wide-range and continuous viscosity measurements, including liquid to solid material transition. The sensor is composed of a small piezoelectric element which enables the horn to resonate. Shear waves are generated by means of the thinner part of the sensor (dipped into the material) confining the acoustic field to the tip to ensure local measurements. The frequency is scanned across the resonating frequencies in order to perform these measurements with the maximum of speed and efficiency. The shear moduli G ′ and G ′′ of the material is deduced from the electrical impedance measurement at the resonance frequencies. In case of rapidly changing materials, such as quick setting cements or polyesters, we have developed a specific fast instrumentation based on the impulse response of the sensor, which realizes very fast measurements, typically 30 measurements per second. Modelization and experiments are reported.

Continuous viscosity measurement of non-Newtonian fluids over a range of shear rates using a mass-detecting capillary viscometer

A newly designed mass-detecting capillary viscometer uses a novel concept to continuously measure non-Newtonian fluids viscosity over a range of shear rates. A single measurement of liquid-mass variation with time replaces the flow rate and pressure drop measurements that are usually required by capillary tube viscometers. Using a load cell and a capillary, we measured change in the mass flow rate through a capillary tube with respect to the time,m(t), from which viscosity and shear rate were mathematically calculated. For aqueous polymer solutions, excellent agreement was found between the results from the mass-detecting capillary viscometer and those from a commercially available rotating viscometer. This new method overcomes the drawbacks of conventional capillary viscometers meassuring non-Newtonian fluid viscosity. First, the mass-detecting capillary viscometer can accurately and consistently measure non-Newtonian viscosity over a wide range of shear rate extending as low as 1 s−1. Second, this design provides simplicity (i. e., ease of operation, no moving parts), and low cost.

Method of Viscosity Measurement Using a New Oscillating-Plate Type Viscometer for High Tempertature Material and its Application to Quality Control of Mold Flux in Continuous Casting Process

A new oscillating-plate type viscometer, which makes instant and continuous measurement of viscosity for high temperature material possible, is developed and utilized. This viscometer is designed for industrial use, and viscosity can be measured automatically with high accuracy and easy operation. The measured value of viscosity is evaluated by using mold flux in continuous casting process, and it is verified that proper control of viscosity and primary crystallization temperature for mold flux yields continuous casting products of good quality and prevents troubles in casting. This method of viscosity measurement is currently used in various areas such as the examination of newly received mold flux, the selection of optimum fluidity characteristics for various casting conditions, and the development and the improvement of mold flux.

Continuous Viscosity Measurements in Order to Observe the Solubility and Miscibility of Carbon Dioxide in a Crude Oil

AbstractA spring‐bellows‐capillary viscometer is now semi‐automatically working and makes, thus, a continuous record of viscosity data possible. These very structure sensitive viscosity measurements have been used to observe the solubility of carbon dioxide in a crude oil, and to demonstrate under proper conditions the lack of miscibility between both compounds. Some measurements with other gases such as nitrogen, methane, and propane are shown for comparison.

The use of the DME for continuous viscosity measurements of liquids

The use of the DME for continuous viscosity measurements of liquids

Capillary Viscometer for Continuous Viscosity Measurement

Capillary Viscometer for Continuous Viscosity Measurement

On The Continuous Measurement of Viscosity

On The Continuous Measurement of Viscosity

Ultrasonic Viscosity Measurements and Industrial Control

The operating principles of the Ultra-Viscoson, an automatic viscosimeter that utilizes ultrasonic energy for the continuous measurement of viscosity, will be discussed. The viscosimeter comprises an ultrasonic probe approximately the size of a fountain pen and an electronic analog computer. The output of the computer is a meter and/or a continuous recorder/controller which are sensitive to the product of density and viscosity of the liquids being measured. Slides illustrating the use of the Ultra-Viscoson in industrial applications for automatic continuous control of processes are presented and discussed. Automatic temperature compensation equipment that permits the viscosity of a liquid to be referred to a particular reference temperature is described, and typical applications of the over-all system for the measurement of viscosity of liquids whose process temperature is varying are outlined.

A New Method for Continuous Viscosity Measurement. General Theory of the Ultra-Viscoson

A new continuous ultrasonic viscometer employing a pulsed resonant exponentially damped magnetostrictive strip is described and treated theoretically. Properties of viscoelastic materials affecting the propagation of transverse elastic waves are derived and are related to the response of the viscometer. Typical applications of the use of the ultrasonic viscometer are presented.