Flow Characteristics of Dilute Polymer Solutions in Micro Tubes

2007 ◽  
Author(s):  
Keizo Watanabe ◽  
Satoshi Ogata ◽  
Munehiko Hirao
Keyword(s):  
Flow Rate ◽  
Polymer Solutions ◽  
Flow Characteristics ◽  
Fused Silica ◽  
Flow Rate Ratio ◽  
Distilled Water ◽  
Number Range ◽  
Micro Piv ◽  
Dilute Polymer Solutions ◽  
Piv Measurement

Pressure drops and velocity profiles for micro tubes were investigated for the laminar flow of distilled water and dilute polymer solutions. The test micro tubes were fused silica capillaries with diameters in the range of 50.2–251.8 μm, and a value of l/d (length/diameter) of about 340. By performing pressure drop measurements, it is shown that the experimental data agree well with the Hagen-Poiseuille equation in the case of Newtonian fluids. On the other hand, the flow rate of dilute polymer solutions increases relative to that of distilled water in the low Reynolds number range. The increased flow rate ratio is a maximum of about 15% in the case of d = 251.8 μm. For the result of the micro PIV measurement, however, there are few differences between the velocity profile of distilled water and the Peo 5 ppm solution.

Micro-PIV Measurement on Transient Flows in Pneumatic MEMS Device for Cell Trapping

2011 ◽  
Author(s):  
Hyun Dong Kim ◽  
Kyung Chun Kim
Keyword(s):  
Flow Characteristics ◽  
Operational Conditions ◽  
Cell Trapping ◽  
Transient Flows ◽  
Micro Piv ◽  
Cell Chip ◽  
Piv Measurement ◽  
Measurement Results ◽  
Equilibrium Region ◽  
Pneumatic Vibrator

This paper presents a micro-PIV measurement for investigation of flow characteristics in a micro chamber for trapping of a live cell. The micro cell chip consisting of pneumatic vibrator arrays and a trap chamber was fabricated through a replica molding technology with a SU-8 mold and Polydimethylsiloxane (PDMS) polymer. The single cell in the trap chamber was manipulated and trapped in the equilibrium region by exploiting the geometrical symmetry of the vibrators. The x-axial velocity of the viscous fluid induced by the deformation of the flexible diaphragms was eliminated or minimized at the center of vibrators. From the measurement results, the proper operational conditions of the vibrators were determined and it is also verified that the particle can be actively manipulated and trapped as desired.

scholarly journals The laminar flow of dilute polymer solutions around circular cylinders

1970 ◽  
Vol 42 (2) ◽  
pp. 269-288 ◽  
Author(s):  
David F. James ◽  
Allan J. Acosta
Keyword(s):  
Heat Transfer ◽  
Relaxation Time ◽  
Polymer Solutions ◽  
Fluid Velocity ◽  
Maxwell Model ◽  
Circular Cylinders ◽  
Stream Velocity ◽  
Dimensionless Group ◽  
Number Range ◽  
Dilute Polymer Solutions

This paper describes the measurements of heat transfer and drag for the flow of dilute polymer solutions around very small cylinders. The thermal experiments were carried out at Reynolds numbers less than 50, and the results establish the dependence of the heat transfer on fluid velocity, cylinder diameter, solution concentration, and polymer molecular weight. The drag measurements were conducted with the same type of solutions and in the same Reynolds-number range. To complement the heat-transfer and drag measurements, the flows around a cylinder and through an orifice were examined visually. These flow-visualization studies showed that the streamline pattern with dilute polymer solutions can be significantly different from that with Newtonian fluids because of viscoelastic effects.An analysis of Rouse's theory of macromolecules shows that for low accelerations a dilute polymer solution behaves mechanically like a Maxwell model. The analysis thereby produces a relaxation time, a single parameter representing the elasticity of the fluid, which can be related to the properties of the solute and solvent. This relaxation time is contained in a new dimensionless group which governs dynamic similarity when induced elastic stresses dominate viscous stresses in the flow around a circular cylinder. The dimensionless group is shown to correlate the thermal data when the heat transfer does not depend on the free stream velocity.

scholarly journals An Experimental Study of the Flow Field Inside the Diffuser Passage of a Laboratory Centrifugal Pump

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Qiaorui Si ◽  
Patrick Dupont ◽  
Annie-Claude Bayeul-Lainé ◽  
Antoine Dazin ◽  
Olivier Roussette ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Design Flow ◽  
Low Flow ◽  
Mean Flow ◽  
Local Pressure ◽  
Flow Rates ◽  
Piv Measurement ◽  
Measurement Results

Measurements are processed on a centrifugal pump model, which works with air and performs with the vane-island type diffuser of a real hydraulic pump, under five flow rates to investigate the internal flow characteristics and their influence on overall pump performance. The mean flow characteristics inside the diffuser are determined by using a miniature three-hole probe connected to an online data acquisition system. The flow structure at the inlet section of the diffuser is analyzed in detail, with a focus on the local pressure loss inside the vaneless gap and incidence angle distributions along the hub-to-shroud direction of the diffuser. Some existing calculations, including leakage effects, are used to evaluate the pressure recovery downstream of the impeller. Furthermore, particle image velocimetry (PIV) measurement results are obtained to help analyze the flow characteristics inside the vane-island diffuser. Each PIV measuring plane is related to one particular diffuser blade-to-blade channel and is analyzed by using the time-averaged method according to seven different relative positions of the impeller. Measurement results show that main loss is produced inside the vaneless part of the diffuser at low flow rates, which might have been caused by the strong rotor–stator interaction. When the impeller flow rate is greater than the diffuser design flow rate, a large fluctuating separated region occurs after the throat of the diffuser on the pressure side. Mean loss originates from the unsteady pressure downstream of the diffuser throat. For better characterization of the separations observed in previous experimental studies, complementary unsteady static pressure measurement campaigns have been conducted on the diffuser blade wall. The unsteadiness revealed by these measurements, as well as theirs effects on the diffuser performance, was then studied.

Retention and Flow Characteristics of Polymer Solutions in Porous Media

1977 ◽  
Vol 17 (02) ◽  
pp. 111-121 ◽  
Author(s):  
J.G. Dominguez ◽  
G.P. Willhite
Keyword(s):  
Porous Media ◽  
Flow Rate ◽  
Polymer Solutions ◽  
Polymer Concentration ◽  
Flow Characteristics ◽  
Porous Matrix ◽  
Polymer Molecules ◽  
Partially Hydrolyzed Polyacrylamide ◽  
Hydrolyzed Polyacrylamide ◽  
Polymer Retention

Abstract Retention and flow characteristics of a solution containing Pusher 700, a high-molecular-weight, partially hydrolyzed polyacrylamide, were studied partially hydrolyzed polyacrylamide, were studied in an 86-md core made by compacting Teflon powder. The quantity, of polymer retained during linear displacement experiments ranged from 10 to 21 mu gm/gm for polymer concentrations of 100 to 500 ppm in 2-percent NaCl solutions. Nearly all retention ppm in 2-percent NaCl solutions. Nearly all retention was attributed to mechanical entrapment because of low polymer adsorption on the Teflon surface. Flow rate affected polymer retention. In increase in velocity was accompanied by polymer retention. Polymer was expelled when the flow rate was Polymer was expelled when the flow rate was reduced. Inaccessible pore volume was about 19 percent of the total pore volume. percent of the total pore volume.Resistance factors in different sections of the core ranged Pam 2 to 10 /or solutions of 100 to 500 ppm polymer concentration in 2-percent NaCl. ppm polymer concentration in 2-percent NaCl. Permeability reduction resulting from polymer Permeability reduction resulting from polymer retention produces the resistance factor in most of the core at a velocity of 3.2 ft/D. Resistance factors in the Teflon cores were two to three times lower than those reported for natural porous media where polymer is also retained by adsorption. Introduction The search for a low-cost, effective mobility control agent is currently focused on dilute aqueous solutions containing partially hydrolyzed polyacrylamides or polysaccharides. Rheological polyacrylamides or polysaccharides. Rheological properties have been studied, including the properties have been studied, including the effects of polymer concentration, shear rate, electrolyte concentration, and type of electrolyte. Correlation of rheological data and models with the flow behavior of polymer solutions in porous media has been complicated by the many interactions that occur between the complex porous matrix and the polymer solutions. Some data have been correlated using non-Newtonian rheological models to describe the variation of fluid viscosity with the apparent shear rate that the fluid experiences as it flows through the tortuous paths in porous media. These correlations have adjustable parameters determined from the particular set of parameters determined from the particular set of data used to develop the correlation. Investigators studying partially hydrolyzed polyacrylamide solutions observed apparent polyacrylamide solutions observed apparent viscosities 5 to 20 times the values measured in a conventional viscometer at the shear rates believed to exist in the porous media. These viscosity increases were not anticipated from the rheological behavior of the fluids. Pye introduced the concept of the resistance factor to quantify this effect. Burcik observed a decrease in the mobility of brine in a Berea sandstone disk that had been previously contacted with partially hydrolyzed previously contacted with partially hydrolyzed polyacrylamide. The mobility reduction persisted polyacrylamide. The mobility reduction persisted even after 100 PV of brine had been flushed through the disk. Burcik concluded that polymer molecules retained in the pore structure by adsorption or mechanical entrapment were hydrophillic and restricted the flow of water. Gogarty made an extensive experimental study of partially hydrolyzed polyacrylamide solutions in porous media and concluded that these polymer porous media and concluded that these polymer solutions reduced the permeability of the porous media. He noosed that polymer retention in natural cores occurred by mechanical entrapment and adsorption. Both mechanisms contributed to the resistance and residual or flushed resistance factors observed with polyacrylamide solutions. Other evidence of interactions between the polymer solution and the porous matrix was found. polymer solution and the porous matrix was found. Adsorption of polymer molecules on the surface of materials present in the porous matrix has been demonstrated in batch adsorption experiments. Material-balance calculations made on the streams entering and leaving porous media following step changes in concentrations show retention of polymer molecules in the porous media. polymer molecules in the porous media. A dependence of polymer retention on flow rate has been reported. Szabo devised a set of static and flow experiments in which polymer adsorption was held to a low level by using silica sand with a small surface area. Mechanical entrapment was found to be the dominant retention mechanism in short sand packs. packs. SPEJ P. 111

scholarly journals Experimental and Numerical Investigations on the Flow Characteristics within Hydrodynamic Entrance Regions in Microchannels

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 317 ◽  
Author(s):  
Haiwang Li ◽  
Binghuan Huang ◽  
Min Wu
Keyword(s):  
Stokes Equations ◽  
Flow Characteristics ◽  
Simulated Data ◽  
Working Fluid ◽  
Separation Flow ◽  
Entrance Length ◽  
Number Range ◽  
Numerical Investigations ◽  
Micro Piv ◽  
Strong Agreement

Flow characteristics within entrance regions in microchannels are important due to their effect on heat and mass transfer. However, relevant research is limited and some conclusions are controversial. In order to reveal flow characteristics within entrance regions and to provide empiric correlation estimating hydrodynamic entrance length, experimental and numerical investigations were conducted in microchannels with square cross-sections. The inlet configuration was elaborately designed in a more common pattern for microdevices to diminish errors caused by separation flow near the inlet and fabrication faults so that conclusions which were more applicable to microchannels could be drawn. Three different microchannels with hydraulic diameters of 100 μm, 150 μm, and 200 μm were investigated with Reynolds (Re) number ranging from 0.5 to 50. For the experiment, deionized water was chosen as the working fluid and microscopic particle image velocimetry (micro-PIV) was adopted to record and analyze velocity profiles. For numerical simulation, the test-sections were modeled and incompressible laminar Navier–Stokes equations were solved with commercial software. Strong agreement was achieved between the experimental data and the simulated data. According to the results of both the experiments and the simulations, new correlations were proposed to estimate entrance length. Re numbers ranging from 12.5 to 15 was considered as the transition region where the relationship between entrance length and Re number converted. For the microchannels and the Reynolds number range investigated compared with correlations for conventional channels, noticeable deviation was observed for lower Re numbers (Re < 12.5) and strong agreement was found for higher Re numbers (Re > 15).

scholarly journals Turbulence Calculations of a Dual-Structure Oxygen Lance for Converter Based on Hydrodynamics

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Hongbin Jia ◽  
Yanxin Li ◽  
Peng Han ◽  
Kun Liu ◽  
Haolei Han ◽  
...  
Keyword(s):  
Flow Rate ◽  
Molten Pool ◽  
Rate Ratio ◽  
Flow Characteristics ◽  
Radial Pressure ◽  
Flow Rate Ratio ◽  
Oxygen Lance ◽  
Special Equipment ◽  
Dual Structure ◽  
Jet Behavior

The oxygen lance is a piece of special equipment in the converter steelmaking process for blowing oxygen into the molten steel. After more than 80 years of development, the structure and function of the oxygen lance have undergone many changes. In this paper, based on the theory of hydrodynamics, the jet behavior characteristics of a dual-structure oxygen lance for the converter are determined and optimized by CFD simulations and compared with those of the traditional-structure oxygen lance. The research results show that multiple jets deflect to the central axis of the oxygen lance during movement and the inclination angle of the nozzle holes influences the jet deflection. A decrease in the nozzle hole angle results in an increase in the mutual suction between the streams. With the increasing flow rate through the large holes in the new dual-structure oxygen lance, the dynamic radial pressure increases at the middle of the jet. The jet flow characteristics of the new dual-structure oxygen lance are better than those of the traditional oxygen lance. Its impact on the molten pool includes greater momentum, a larger impact area, and a more uniform and powerful stirring of the molten pool. A nozzle angle of 14° combined with a flow rate ratio of 65% and a nozzle angle of 17° combined with a flow rate ratio of 35% are the optimal parameters for the new dual-structure oxygen lance.

Temperature-Dependent Property Effects on Laminar Flow Characteristics in a Rectangular Microchannel

2001 ◽  
Author(s):  
Ho Joon Park ◽  
Sang Young Son ◽  
Mun Cheol Choi ◽  
Geunbae Lim ◽  
In-Seob Song ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Laminar Flow ◽  
Flow Resistance ◽  
Flow Characteristics ◽  
Working Fluid ◽  
Micro Channel ◽  
Temperature Dependent ◽  
Micro Piv ◽  
Piv Measurement ◽  
Dependent Property

Abstract This paper investigated experimentally effects of the temperature-dependent property on the laminar flow characteristics in the micro-channel, where water was used as a working fluid. A rectangular straight micro-channel was fabricated with the dimension of 57 μm (H) × 200 μm (W) × 48050 μm (L), in which the resistance temperature detectors (RTDs) were integrated to measure precise temperatures of the fluid directly on the inside-surface of the channel wall. A micro-heater was also installed at the outlet of the channel to generate the heat flux. We measured pressure drop by increasing mass flow rate and the applied heating power. At the same time, micro-Particle Image Velocimetry (micro-PIV) [1] measured the detailed velocity fields along the microchannel, where the wall temperature varied. Based on the pressure drop and Micro-PIV measurement, it was determined that the variation of the fluid property along the microchannel has an effect significantly on flow resistance but not considerably on the velocity profile. Also, it was observed that flow resistance and velocity field shows a good agreement with those estimated in the macro laminar theory under our experimental conditions.

Sign in / Sign up

Export Citation Format

Share Document