Flow rate–pressure drop relation for shear-thinning fluids in narrow channels: approximate solutions and comparison with experiments

2021 ◽  
Vol 923 ◽  
Author(s):  
Evgeniy Boyko ◽  
Howard A. Stone
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Approximate Solutions ◽  
Shear Thinning ◽  
Narrow Channels ◽  
Shear Thinning Fluids ◽  
Comparison With Experiments

Abstract

On the elastohydrodynamic analysis of shear-thinning fluids

2007 ◽  
Vol 463 (2088) ◽  
pp. 3271-3290 ◽  
Author(s):  
J.Y Jang ◽  
M.M Khonsari ◽  
S Bair
Keyword(s):  
Film Thickness ◽  
Numerical Solutions ◽  
Elastohydrodynamic Lubrication ◽  
Shear Thinning ◽  
Line Contact ◽  
Carreau Model ◽  
Shear Thinning Fluids ◽  
Realistic Prediction ◽  
Comparison With Experiments ◽  
Ehl Contact

Realistic prediction of the characteristics of the elastohydrodynamic lubrication (EHL) contact requires consideration of the appropriate constitutive equation for the lubricant. In many applications, the lubricant exhibits a shear-thinning behaviour which significantly affects the film thickness. In this paper, we present a generalized formulation that can efficiently treat shear-thinning fluids with provision for compressibility in the EHL line contact. Specifically, the Carreau model and the sinh-law model are investigated. An extensive set of numerical solutions and comparison with experiments reveal that the Carreau equation properly captures the film thickness behaviour under both rolling and sliding conditions.

Microchannels in series connected via a contraction/expansion section

2002 ◽  
Vol 459 ◽  
pp. 187-206 ◽  
Author(s):  
WING YIN LEE ◽  
MAN WONG ◽  
YITSHAK ZOHAR
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Flow Direction ◽  
Pressure Sensors ◽  
Narrow Channel ◽  
Narrow Channels ◽  
Pressure Losses ◽  
Transition Section ◽  
In Series ◽  
Straight Segments

Fluid flow in microdevices consisting of pairs of microchannels in series was studied. The dimensions of the channels are about 40 μm × 1 μm × 2000 μm for the wide and about 20 μm × 1 μm × 2000 μm for the narrow channels. Pairs of wide and narrow channels, with integrated pressure sensors, are connected via transition sections with included angles varying from 5° to 180°. Minor pressure losses (not due to friction) were studied by passing nitrogen through the channels under inlet pressures up to 60 p.s.i. Each device was tested in the contraction mode, flow from wide to narrow channel, and in the opposite expansion mode, flow from narrow to wide channel. Mass flow rate was first measured as a function of the overall pressure drop. The detailed pressure distribution along the straight segments and around the transition section was then measured in order to understand the flow pattern. The Reynolds number for these flows is less than 1, suggesting the flow to be of the Hele-Shaw type with no separation such that the results for all the devices should be similar. However, the flow rate was found to decrease and the pressure loss to increase significantly with increasing included angle of the transition section, regardless of the flow direction. Flow separation due to the transition sections, if indeed there is any, cannot explain the large pressure drop since the kinetic energy is negligible.

Study of fluid flow through a channel deformed by piezoelement

2018 ◽  
Vol 13 (3) ◽  
pp. 1-10 ◽  
Author(s):  
I.Sh. Nasibullayev ◽  
E.Sh Nasibullaeva ◽  
O.V. Darintsev
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Flow Rate ◽  
Contact Surface ◽  
Piezoelectric Element ◽  
Neumann Boundary ◽  
Differential Pressure ◽  
Physical Parameters ◽  
Flow Through

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.

Pressure Drop Measurements for Air Flow Through Open-Cell Aluminum Foam

2004 ◽  
Author(s):  
Nihad Dukhan ◽  
Angel Alvarez
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Flow Rate ◽  
Aluminum Foam ◽  
Flow Direction ◽  
The Other ◽  
Turbulent Regime ◽  
Thick Sample ◽  
Open Cell ◽  
Two Samples

Wind-tunnel pressure drop measurements for airflow through two samples of forty-pore-per-inch commercially available open-cell aluminum foam were undertaken. Each sample’s cross-sectional area perpendicular to the flow direction measured 10.16 cm by 24.13 cm. The thickness in the flow direction was 10.16 cm for one sample and 5.08 cm for the other. The flow rate ranged from 0.016 to 0.101 m3/s for the thick sample and from 0.025 to 0.134 m3/s for the other. The data were all in the fully turbulent regime. The pressure drop for both samples increased with increasing flow rate and followed a quadratic behavior. The permeability and the inertia coefficient showed some scatter with average values of 4.6 × 10−8 m2 and 2.9 × 10−8 m2, and 0.086 and 0.066 for the thick and the thin samples, respectively. The friction factor decayed with the Reynolds number and was weakly dependent on the Reynolds number for Reynolds number greater than 35.

Simultaneous Measuring Method for Both Volumetric Flow Rates of Air-Water Mixture Using a Turbine Flowmeter

1996 ◽  
Vol 118 (1) ◽  
pp. 29-35 ◽  
Author(s):  
K. Minemura ◽  
K. Egashira ◽  
K. Ihara ◽  
H. Furuta ◽  
K. Yamamoto
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Oil Field ◽  
Liquid Density ◽  
Water Mixture ◽  
Rotor Speed ◽  
Flow Rates ◽  
Field Development ◽  
Turbine Flowmeter

A turbine flowmeter is employed in this study in connection with offshore oil field development, in order to measure simultaneously both the volumetric flow rates of air-water two-phase mixture. Though a conventional turbine flowmeter is generally used to measure the single-phase volumetric flow rate by obtaining the rotational rotor speed, the method proposed additionally reads the pressure drop across the meter. After the pressure drop and rotor speed measured are correlated as functions of the volumetric flow ratio of the air to the whole fluid and the total volumetric flow rate, both the flow rates are iteratively evaluated with the functions on the premise that the liquid density is known. The evaluated flow rates are confirmed to have adequate accuracy, and thus the applicability of the method to oil fields.

scholarly journals Effect of Surfactants on Gas Holdup in Shear-Thinning Fluids

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Shaobai Li ◽  
Siyuan Huang ◽  
Jungeng Fan
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Sodium Dodecyl ◽  
Shear Thinning ◽  
Gas Holdup ◽  
Bubble Columns ◽  
Gas Velocity ◽  
Shear Thinning Fluids ◽  
Liquid Surface Tension ◽  
Superficial Gas Velocity

In this study, the gas holdup of bubble swarms in shear-thinning fluids was experimentally studied at superficial gas velocities ranging from 0.001 to 0.02 m·s−1. Carboxylmethyl cellulose (CMC) solutions of 0.2 wt%, 0.6 wt%, and 1.0 wt% with sodium dodecyl sulfate (SDS) as the surfactant were used as the power-law (liquid phase), and nitrogen was used as the gas phase. Effects of SDS concentration, rheological behavior, and physical properties of the liquid phase and superficial gas velocity on gas holdup were investigated. Results indicated that gas holdup increases with increasing superficial gas velocity and decreasing CMC concentration. Moreover, the addition of SDS in CMC solutions increased gas holdup, and the degree increased with the surfactant concentration. An empirical correlation was proposed for evaluating gas holdup as a function of liquid surface tension, density, effective viscosity, rheological property, superficial gas velocity, and geometric characteristics of bubble columns using the experimental data obtained for the different superficial gas velocities and CMC solution concentrations with different surfactant solutions. These proposed correlations reasonably fitted the experimental data obtained for gas holdup in this system.

Stability of Shear-Thickening Liquids Between Rotating Cylinders

2010 ◽  
Author(s):  
Nariman Ashrafi ◽  
Habib Karimi Haghighi
Keyword(s):  
Couette Flow ◽  
Dynamical Behavior ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Taylor Vortex ◽  
Shear Dependent Viscosity ◽  
Shear Thinning Fluids ◽  
Shear Thickening Fluids ◽  
The Stability ◽  
Dependent Viscosity

The effects of nonlinearities on the stability are explored for shear thickening fluids in the narrow-gap limit of the Taylor-Couette flow. It is assumed that shear-thickening fluids behave exactly as opposite of shear thinning ones. A dynamical system is obtained from the conservation of mass and momentum equations which include nonlinear terms in velocity components due to the shear-dependent viscosity. It is found that the critical Taylor number, corresponding to the loss of stability of Couette flow becomes higher as the shear-thickening effects increases. Similar to the shear thinning case, the Taylor vortex structure emerges in the shear thickening flow, however they quickly disappear thus bringing the flow back to the purely azimuthal flow. Naturally, one expects shear thickening fluids to result in inverse dynamical behavior of shear thinning fluids. This study proves that this is not the case for every point on the bifurcation diagram.

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