scholarly journals Precise Method to Estimate the Herschel-Bulkley Parameters from Pipe Rheometer Measurements

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 157
Author(s):  
Elie Magnon ◽  
Eric Cayeux
Keyword(s):  
Rheological Behavior ◽  
Rheological Model ◽  
Flow Behavior ◽  
Process Efficiency ◽  
Low Flow ◽  
Model Parameters ◽  
Prediction Errors ◽  
Flow Behavior Index ◽  
Short Period ◽  
Wide Range

Accurate characterization of the rheological behavior of non-Newtonian fluids is critical in a wide range of industries as it governs process efficiency, safety, and end-product quality. When the rheological behavior of fluid may vary substantially over a relatively short period of time, it is desirable to measure its viscous properties on a more continuous basis than relying on spot measurements made with a viscometer on a few samples. An attractive solution for inline rheological measurements is to measure pressure gradients while circulating fluid at different bulk velocities in a circular pipe. Yet, extracting the rheological model parameters may be challenging as measurement uncertainty may influence the precision of the model fitting. In this paper, we present a method to calibrate the Herschel-Bulkley rheological model to a series of differential pressure measurements made at variable bulk velocities using a combination of physics-based equations and nonlinear optimization. Experimental validation of the method is conducted on non-Newtonian shear-thinning fluid based on aqueous solutions of polymers and the results are compared to those obtained with a scientific rheometer. It is found that using a physics-based method to estimate the parameters contributes to reducing prediction errors, especially at low flow rates. With the tested polymeric fluid, the proportion difference between the estimated Herschel-Bulkley parameters and those obtained using the scientific rheometer are −24% for the yield stress, 0.26% for the consistency index, and 0.30% for the flow behavior index. Finally, the computation requires limited resources, and the algorithm can be implemented on low-power devices such as an embedded single-board computer or a mobile device.

Development of an Efficient Phase Separator for Space and Ground Applications

2016 ◽  
Author(s):  
Xiongjun Wu ◽  
Greg Loraine ◽  
Chao-Tsung Hsiao ◽  
Georges L. Chahine
Keyword(s):  
Swirling Flow ◽  
Flow Behavior ◽  
Space Station ◽  
Low Flow ◽  
Design Parameters ◽  
Two Phase ◽  
Flow Rates ◽  
Void Fractions ◽  
Wide Range ◽  
Phase Separator

The limited amount of liquids and gases that can be carried to space makes it imperative to recycle and reuse these fluids for extended human operations. During recycling processes gas and liquid phases are often intermixed. In the absence of gravity, separating gases from liquids is challenging due to the absence of buoyancy. This paper discusses a phase separator that is capable of efficiently and reliably separating gas-liquid mixtures of both high and low void fractions in a wide range of flow rates that is applicable to reduced and zero gravity environments. The phase separator consists of two concentric cylindrical chambers. The fluid introduced in the space between the two cylinders enters the inner cylinder through tangential slots and generates a high intensity swirling flow. The geometric configuration is selected to make the vortex swirl intense enough to lead to early cavitation which forms a cylindrical vaporous core at the axis even at low flow rates. Taking advantage of swirl and cavitation, the phase separator can force gas out of the liquid into the central core of the vortex even at low void fraction. Gas is extracted from one end of the cylinder axial region and liquid is extracted from the other end. The phase separator has successfully demonstrated its capability to reduce mixture void fractions down to 10−8 and to accommodate incoming mixture gas volume fractions as high as 35% in both earth and reduced gravity flight tests. The phase separator is on track to be tested by NASA on the International Space Station (ISS). Additionally, the phase separator design exhibits excellent scalability. Phase separators of different dimensions, with inlet liquid flow rates that range from a couple of GPMs to a few tens of GPMs, have been built and tested successfully in the presence and absence of the gravity. Extensive ground experiments have been conducted to study the effects of main design parameters on the performance of the phase separator, such as the length and diameter of the inner cylinder; the size, location, and layout of injection slots and exit orifices, etc., on the swirling flow behavior, and on the gas extraction performance. In parallel, numerical simulations, utilizing a two-phase Navier-Stokes flow solver coupled with bubble dynamics, have been conducted extensively to facilitate the development of the phase separator. These simulations have enabled us to better understand the physics behind the phase separation and provided guideline for system parts optimization. This paper describes our efforts in developing the passive phase separator for both space and ground applications.

scholarly journals Improving streamflow predictions at ungauged locations with real-time updating: application of an EnKF-based state-parameter estimation strategy

2014 ◽  
Vol 18 (10) ◽  
pp. 3923-3936 ◽  
Author(s):  
X. Xie ◽  
S. Meng ◽  
S. Liang ◽  
Y. Yao
Keyword(s):  
Real Time ◽  
Land Surface ◽  
Hydrological Model ◽  
Similarity Measures ◽  
State Parameter ◽  
Model Parameters ◽  
Prediction Errors ◽  
Distributed Hydrological Model ◽  
Streamflow Prediction ◽  
Short Period

Abstract. The challenge of streamflow predictions at ungauged locations is primarily attributed to various uncertainties in hydrological modelling. Many studies have been devoted to addressing this issue. The similarity regionalization approach, a commonly used strategy, is usually limited by subjective selection of similarity measures. This paper presents an application of a partitioned update scheme based on the ensemble Kalman filter (EnKF) to reduce the prediction uncertainties. This scheme performs real-time updating for states and parameters of a distributed hydrological model by assimilating gauged streamflow. The streamflow predictions are constrained by the physical rainfall-runoff processes defined in the distributed hydrological model and by the correlation information transferred from gauged to ungauged basins. This scheme is successfully demonstrated in a nested basin with real-world hydrological data where the subbasins have immediate upstream and downstream neighbours. The results suggest that the assimilated observed data from downstream neighbours have more important roles in reducing the streamflow prediction errors at ungauged locations. The real-time updated model parameters remain stable with reasonable spreads after short-period assimilation, while their estimation trajectories have slow variations, which may be attributable to climate and land surface changes. Although this real-time updating scheme is intended for streamflow predictions in nested basins, it can be a valuable tool in separate basins to improve hydrological predictions by assimilating multi-source data sets, including ground-based and remote-sensing observations.

Flow Speed Measurement and Rheometry by Pulsed Neutron Activation

1989 ◽  
Vol 111 (3) ◽  
pp. 337-341 ◽  
Author(s):  
K. G. A. Porges ◽  
S. A. Cox ◽  
C. Herzenberg ◽  
C. Kampschoer
Keyword(s):  
Laminar Flow ◽  
Neutron Activation ◽  
Flow Behavior ◽  
Industrial Plant ◽  
Rheological Parameters ◽  
Slurry Flow ◽  
Flow Behavior Index ◽  
Processing Scheme ◽  
Wide Range ◽  
Pulsed Neutron

Pulsed Neutron Activation (PNA) is a means of noninvasive flow velocity measurement based on tagging the flowing medium with a short-lived radioactivity. Previous work with salt or dye-tagging showed poor accuracy in turbulent and failed in laminar flow when conventional data processing was used. However, use of a data acquisition and processing scheme that is based on tag dispersion modelling can produce absolute values over a wide range of flow speeds and regimes with high accuracy. For non-Newtonian/laminar flow, rheological information can also be obtained. The inherently non-intrusive nature of PNA tagging makes this scheme available for slurry measurements. The performance of PNA in slurry flow at up to 60 percent solid content was compared to full-flow diversion and weighing. Errors ranged from less than 0.2 percent at high Reynolds’ numbers to about 2 percent for paste flow. Rheological parameters (yield shear stress or flow behavior index) could be determined with an accuracy that compared to that of a spindle viscometer with grab-samples. The PNA scheme thus offers a unique means of studying slurry flow in a dedicated laboratory facility, or of providing calibration for other flowmeters in an industrial plant through temporary installation by a team of expert consultants.

scholarly journals Using the Mitschka-Briggs-Steffe Method for Evaluation of Cactus Pear Concentrated Pulps Rheological Behavior

2012 ◽  
Vol 7 (6) ◽  
Author(s):  
Pedro Esteves Duarte Augusto ◽  
Marcelo Cristianini ◽  
Albert Ibarz
Keyword(s):  
Rheological Behavior ◽  
Process Design ◽  
Flow Behavior ◽  
Single Equation ◽  
Rheological Parameters ◽  
Rheological Characterization ◽  
Flow Behavior Index ◽  
Cactus Pear ◽  
Average Value ◽  
Product And Process

The rheological characterization of food is important for efficient product and process design. Although its importance in semi-arid regions, there are only a few studies regarding the rheological properties of cactus pear products in the literature. The present work has used the Mitschka-Briggs-Steffe method for evaluation of the rheological behavior of cactus pear concentrated pulps. The pulps have shown pseudoplastic behavior. The flow behavior index (n) shows a constant value in the evaluated conditions, and its average value was considered in the evaluated temperature and concentration range. The consistency index (k) has shown dependency of concentration and temperature, being well modeled by a modified Arrhenius equation. Thus, the rheological parameters of cactus pear concentrated pulps can be obtained using a single equation, related with temperature, concentration and shear rate. The obtained data are potentially useful for future studies on product development, food properties and process design.

Rheology and Rotational Rheometry of Concentrated Clay Based Ceramic Suspensions: Steps From Measured to Relevant Data

2010 ◽  
Author(s):  
Jana Andertova´ ◽  
Frantisˇek Rieger
Keyword(s):  
Experimental Data ◽  
Rheological Behavior ◽  
Flow Behavior ◽  
Slip Casting ◽  
Rheological Parameters ◽  
Technological Parameters ◽  
Flow Curves ◽  
Rotational Viscometer ◽  
Flow Behavior Index ◽  
Ceramic Suspensions

The rheological behavior of ceramic suspensions affects significantly wet ceramic processing. On the base of knowledge of rheological parameters the technological parameters of various processes (mixing, batching, spray drying, slip casting, of rheological parameters the selection of proper geometry and sensors must be done. From the data measured the flow curves must be designed and parameters of appropriate rheological models must be calculated. The power-law is the simplest model mostly used for description of rheological behavior of non-Newtonian fluids. Using this model, the dependence of shear stress on shear rate can be expressed. The aim of this paper is to show how the flow curves necessary for parameters of rheological model evaluation can be obtained from primary experimental data received from measurements on rotational viscometer. The two arrangements of rotational viscometer method were used in rheological measurements. The procedure of experimental data to obtain parameters K (coefficient of consistency) and n (flow behavior index) is presented.

INFLUENCE OF SPACE HOLDER ON RHEOLOGICAL BEHAVIOR OF COPPER FEEDSTOCKS FOR METAL INJECTION MOLDING

2015 ◽  
Vol 76 (6) ◽  
Author(s):  
Mohammad Dahar Kamal Bahrin ◽  
Nor ‘Aini Wahab ◽  
Nor Amalina Nordin ◽  
Muhammad Hussain Ismail ◽  
Ismail Nasiruddin Ahmad
Keyword(s):  
Injection Molding ◽  
Rheological Behavior ◽  
Flow Behavior ◽  
Palm Stearin ◽  
Metal Injection Molding ◽  
Plastic Behavior ◽  
Flow Behavior Index ◽  
Space Holder ◽  
Porous Copper

The characterization of MIM feedstock consisting of 63 vol% of copper powder with a binder system consisting of palm stearin (PS) and low density polyethylene (LDPE) was studied. To achieve porous structure, sodium chloride (NaCl) was added as a space holder. The effect of shear rate (s-1), temperature (oC) and viscosity (Pa.s) on the rheological behavior of solid and porous copper feedstocks were investigated by using the Rosand RH2000 Capillary Rheometer at temperatures of 160, 170 and 180oC. The feedstocks achieved desirable injection molding characteristics such as pseudo-plastic behaviour, stable flow, flow behavior index less than 1 (n<1) and low activation energy (E). It can be concluded from the analysis that both feedstocks showed a good pseudo-plastic behavior within acceptable ranges in MIM. 

scholarly journals Utilization of Bitter orange seeds as a novel source for recovery of pectin: Compositional and rheological characterization

2021 ◽  
Author(s):  
Mohammad Nejatian ◽  
Diako Khodaei ◽  
Hassan Ahmadi Gavlighi ◽  
Azizollaah Zargaraan
Keyword(s):  
Flow Behavior ◽  
Rheological Characterization ◽  
Flow Behavior Index ◽  
Bitter Orange ◽  
Rheological Measurements ◽  
Wide Range ◽  
Neutral Sugars ◽  
Strain Sweep ◽  
Increasing Temperature ◽  
First Time

Abstract The seeds from bitter orange, a by-product from the juice making step, hold the potential to facilitate novel, easy yet high quality pectin extraction. To test this hypothesis, the pectin from orange seeds (OSP) were extracted by distilled water and its compositional parameters and rheological behavior then evaluated. Results showed that galacturonic acid was the major component of OSP (~ 425 mg/g) confirming the purity of extracted pectin, followed by glucose and some minor neutral sugars. Mw, Rn and, Rz for the OSP were 4511.8 (kDa), 61 (nm), and 61.1 (nm), respectively. Rheological measurements showed shear-thinning behavior for OSP that by increasing temperature from 5 to 45 oC, the viscosity of the gum decreased. Power law fitted as the best rheological model describing the flow behavior of OSP. Strain sweep dynamic rheological measurements confirmed an entangled network structure for OSP and the addition of NaCl to the gum dispersion, decreased the consistency coefficient from 35.6 to 23.18 Pa.sn, while the flow behavior index remained unchanged. These results demonstrate for the first time that the OSP can be used as a new source of pectin, with likely a wide range of applications in food industry.

scholarly journals Caesalpinia pulcherrima seed galactomannan on rheological properties of dairy desserts

2020 ◽  
Vol 50 (6) ◽  
Author(s):  
Stella Regina Arcanjo Medeiros ◽  
Victor Alves de Oliveira ◽  
Amanda Mazza Cruz de Oliveira ◽  
Marjory Lima Holanda Araujo ◽  
Judith Pessoa de Andrade Feitosa ◽  
...  
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Milk Protein ◽  
Flow Behavior ◽  
Flow Behavior Index ◽  
N Yield ◽  
Dynamic Rheological Behavior ◽  
Behavior Index

ABSTRACT: Dairy desserts containing Caesalpinia pulcherrima seed galactomannan were evaluated to determine their static and dynamic rheological behaviors. Variations in consistency index (k), flow behavior (n), yield stress and thixotropy of the desserts indicated that the galactomannan caused an increase in the shear stress and apparent viscosity of the system. All samples exhibited shear-thinning behavior with flow behavior index values (n) between 0.06 and 0.37. Dynamic rheological behavior was evaluated for MD (high solid levels) and MD/2 (half the amount of solids) groups, and both G’ and G’’ moduli were depended on the frequency. The MD and MD/2 groups showed variations in the elastic modulus (G’) throughout the temperature range (mainly at 50 °C), showing greater sensitivity at high temperatures. C. pulcherrima galactomannan was able to promote synergism with starch, milk protein and sucrose and to improve the development of stronger and more resistant gels.

scholarly journals Aqueous Solutions of Polyethoxylated Fatty Alcohols Rheological behavior and superficial properties

2019 ◽  
Vol 70 (2) ◽  
pp. 382-386
Author(s):  
Andra Tamas ◽  
Sabina Nitu
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Aqueous Solutions ◽  
Rheological Behavior ◽  
Flow Behavior ◽  
Fatty Alcohols ◽  
Flow Behavior Index ◽  
Foaming Power ◽  
Newtonian Behavior ◽  
Behavior Index

The paper presents the study of the rheological and superficial behavior (foaming power and wetting capacity) of some aqueous solutions with polyethoxylated fatty alcohols content. The influence of fatty alcohols concentration and their degree of ethoxylation as well as that of temperature on the rheological behavior was determined from the dependences between the shear stress t and the shear rate. The results demonstrate that all the studied solutions have non-Newtonian behavior, with flow behavior index smaller than 1.

Statistical Evaluation of Interstate 4 Traffic Prediction System

2003 ◽  
Vol 1856 (1) ◽  
pp. 16-24 ◽  
Author(s):  
Sherif Ishak ◽  
Haitham Al-Deek
Keyword(s):  
Traffic Management ◽  
Traffic Prediction ◽  
Model Parameters ◽  
Prediction Errors ◽  
Prediction System ◽  
Traveler Information ◽  
Planning Stage ◽  
Traffic Conditions ◽  
Wide Range ◽  
Prediction Systems

Short-term traffic prediction systems have received considerable attention in the past few years as a means to support advanced traveler information and traffic management systems. Predictive information allows transportation system users to make better trip decisions at the pretrip planning stage and en route. A comprehensive statistical analysis of the traffic prediction system performance implemented on the 40-mi corridor of Interstate 4 in Orlando, Florida, is presented. The system was evaluated under a wide range of traffic conditions and various model parameters. The prediction performance in terms of prediction errors was examined with both link-based and path-based approaches.

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