scholarly journals Thinning of Emulsion Water-in-Oil Films Stabilized with Modified Aluminum Hydroxide under Influence of Applied Pressure Drop

Soft ◽  
2014 ◽  
Vol 03 (01) ◽  
pp. 11-17
Author(s):  
Alla V. Nushtaeva
Keyword(s):  
Pressure Drop ◽  
Aluminum Hydroxide ◽  
Applied Pressure ◽  
Oil Films

scholarly journals The Effect of Very Cohesive Ultra-Fine Particles in Mixtures on Compression, Consolidation, and Fluidization

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 439
Author(s):  
Abbas Kamranian Marnani ◽  
Andreas Bück ◽  
Sergiy Antonyuk ◽  
Berend van Wachem ◽  
Dominique Thévenin ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Binary Mixture ◽  
Packing Density ◽  
Fine Particles ◽  
Bulk Material ◽  
Applied Pressure ◽  
Gas Velocity ◽  
History Effect ◽  
Ultra Fine Particles ◽  
Linear Manner

This paper focuses on the effect of ultra-fine ( d < 10 µm) powders in mixtures with fine ( d < 100 µm) bulk material on compression processes and also evaluates the re-fluidization behavior of the compressed bed (history effect). Achieving this goal, different mixtures of fine and ultra-fine Ground-Carbonate-Calcium were compressed at three pressure levels. The results show that by increasing the applied pressure, the compressibility decreases due to change in compaction regime. Subsequently, for the higher pressure, the slope of packing density versus applied stress curves is noticeably different. However, this slope does not depend on the size distribution of mixtures, but on the type of material. Comparing fluidization and re-fluidization curves (bed pressure drop vs. gas velocity) shows an increase in the maximum bed pressure drop ( Δ P p e a k ) for re-fluidization. By increasing the portion of ultra-fine particles in the binary mixture, Δ P p e a k increases in a non-linear manner. Furthermore, the incipient fluidization point moves to a higher gas velocity. After compression, the peak of the bed pressure drop in the re-fluidization test happens at a lower gas velocity than in the initial fluidization test. Thus, the slope of the loading curve is much larger for re-fluidization. The opposite is observed for the unloading curves.

Geometric Optimisation of Forced Convection in Cooling Channels With Internal Heat Generation

2010 ◽  
Author(s):  
Olabode T. Olakoyejo ◽  
Tunde Bello-Ochende ◽  
Josua P. Meyer
Keyword(s):  
Pressure Drop ◽  
Forced Convection ◽  
Heat Generation ◽  
Applied Pressure ◽  
Internal Heat ◽  
Solid Material ◽  
Internal Heat Generation ◽  
Geometric Optimization ◽  
Peak Temperature ◽  
Cooling Channels

This paper presents a three dimensional geometric optimization of cooling channels in forced convection with internal heat generation within the solid. Three configurations were studied, circular channels, square channels and rectangular channels with different porosities. The configurations were optimized in such a way that the peak temperature is minimum. The optimization is subject to the constraint of fixed volume and solid material. The fluid is forced through the channels by the pressure difference across the channels. The structure has two degrees of freedom as design variables: channel hydraulic diameter and channel-to-channel spacing. The results obtained show the behaviour of the applied pressure drop on the optimized geometry. Results also show that as pressure drop increases the minimized peak temperature decreases.

scholarly journals An Easy Method for Pressure Measurement in Microchannels Using Trapped Air Compression in a One-End-Sealed Capillary

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 914
Author(s):  
Feng Shen ◽  
Mingzhu Ai ◽  
Jianfeng Ma ◽  
Zonghe Li ◽  
Sen Xue
Keyword(s):  
Pressure Drop ◽  
Pressure Measurement ◽  
Applied Pressure ◽  
Fluid Pressure ◽  
Principal Component ◽  
Ideal Gas ◽  
Easy Method ◽  
Trapped Air ◽  
Additional Equipment ◽  
Scale Range

Pressure is one basic parameter involved in microfluidic systems. In this study, we developed an easy capillary-based method for measuring fluid pressure at one or multiple locations in a microchannel. The principal component is a commonly used capillary (inner diameter of 400 μm and 95 mm in length), with one end sealed and calibrated scales on it. By reading the height (h) of an air-liquid interface, the pressure can be measured directly from a table, which is calculated using the ideal gas law. Many factors that affect the relationship between the trapped air volume and applied pressure (papplied) have been investigated in detail, including the surface tension, liquid gravity, air solubility in water, temperature variation, and capillary diameters. Based on the evaluation of the experimental and simulation results of the pressure, combined with theoretical analysis, a resolution of about 1 kPa within a full-scale range of 101.6–178 kPa was obtained. A pressure drop (Δp) as low as 0.25 kPa was obtained in an operating range from 0.5 kPa to 12 kPa. Compared with other novel, microstructure-based methods, this method does not require microfabrication and additional equipment. Finally, we use this method to reasonably analyze the nonlinearity of the flow-pressure drop relationship caused by channel deformation. In the future, this one-end-sealed capillary could be used for pressure measurement as easily as a clinical thermometer in various microfluidic applications.

Pressure-driven flow across a hyperelastic porous membrane

2019 ◽  
Vol 871 ◽  
pp. 742-754 ◽  
Author(s):  
Ryungeun Song ◽  
Howard A. Stone ◽  
Kaare H. Jensen ◽  
Jinkee Lee
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Darcy’S Law ◽  
Applied Pressure ◽  
Soft Materials ◽  
Porous Membrane ◽  
Darcy's Law ◽  
Membrane Thickness ◽  
Pressure Driven Flow ◽  
Pressure Driven

We report an experimental investigation of pressure-driven flow of a viscous liquid across thin polydimethylsiloxane (PDMS) membranes. Our experiments revealed a nonlinear relation between the flow rate $Q$ and the applied pressure drop $\unicode[STIX]{x0394}p$, in apparent disagreement with Darcy’s law, which dictates a linear relationship between flow rate, or average velocity, and pressure drop. These observations suggest that the effective permeability of the membrane decreases with pressure due to deformation of the nanochannels in the PDMS polymeric network. We propose a model that incorporates the effects of pressure-induced deformation of the hyperelastic porous membrane at three distinct scales: the membrane surface area, which increases with pressure, the membrane thickness, which decreases with pressure, and the structure of the porous material, which is deformed at the nanoscale. With this model, we are able to rationalize the deviation between Darcy’s law and the data. Our result represents a novel case in which macroscopic deformations can impact the microstructure and transport properties of soft materials.

scholarly journals Analysis of Implementation Effectiveness of Two Working Fluids Characterized by Different Viscoelastic Characteristics at Hydrodynamic Impact on the Borehole Bottom Zone

2019 ◽  
Vol 18 (2) ◽  
pp. 164-170
Author(s):  
K. S. Kupavykh ◽  
A. S. Kupavykh ◽  
V. A. Morenov
Keyword(s):  
Pressure Drop ◽  
Acid Solution ◽  
Applied Pressure ◽  
Working Fluid ◽  
Hydrodynamic Impact ◽  
Technology Application ◽  
Analytical Studies ◽  
Geological Conditions ◽  
Pressure Pulses ◽  
Viscoelastic Characteristics

Combination of hydrodynamic impact on the formation with acid treatment may be seen as a promising direction in the field of well development and repair in complex geological conditions. With multiple repetition of hydraulic shocks in conjunction with the injection of acid solution, the depth and opening of cracks gradually increases, which contributes to a deeper penetration of the acid solution into the reservoir. The article presents analytical studies, which are aimed at determining the effectiveness of applying the technology of hydrodynamic impact on the bottomhole zone of an oil reservoir when using two fluids with different viscoelastic characteristics as a working fluid. They are devoted to determining the pressure drop at the borehole bottom depending on the initial applied pressure at the wellhead, the velocity of the shock wave, the viscosity of the working and well fluid, and their quantity. These studies were based on the well-known models of Thomson – Tаt and Maxwell, considering viscous liquid flow. The dependence obtained proves that with an increase in the pressure pulse generated at the wellhead, the development of pressure pulses at the borehole bottom is a power-law dependence, and with significant volumes of fluid in contact with the bottomhole formation zone, the pressure drop generated at the borehole bottom does not depend only on pressure pulses generated at the wellhead, but also on the dynamic viscosity of this fluid. Conducted studies have shown the effectiveness of hydrodynamic impact technology application when using two liquids with different viscoelastic characteristics and obtaining a synergistic effect during the development and repair of wells in low-permeable reservoirs. Analytical studies were based on data from previously conducted experimental industrial tests on the operating injection well.

Transient Filtration in a Porous Elastic Cylinder

1976 ◽  
Vol 43 (4) ◽  
pp. 594-598 ◽  
Author(s):  
D. E. Kenyon
Keyword(s):  
Pressure Drop ◽  
Contact Stress ◽  
Tube Wall ◽  
Applied Pressure ◽  
Elastic Cylinder ◽  
Constant Volume ◽  
Thin Layers ◽  
Time Dependent ◽  
Porous Tube ◽  
Direction Opposite

The time-dependent filtration of liquid through the wall of a soft, porous tube can be quite unlike that of a hard, porous tube. Under conditions described, the seepage is limited to thin layers near each surface, and in one of these layers, liquid seepage proceeds in a direction opposite to the sense of the applied pressure drop across the tube wall. This occurs because it is impossible to produce isotropic contact stress in the solid if kept at constant volume by the slowness of seepage. The liquid must then bear the entire isotropic stress.

scholarly journals Viscous flow in a soft valve

2017 ◽  
Vol 836 ◽  
Author(s):  
K. Park ◽  
A. Tixier ◽  
A. H. Christensen ◽  
S. F. Arnbjerg-Nielsen ◽  
M. A. Zwieniecki ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Viscous Flow ◽  
Flow Rate ◽  
Ad Hoc ◽  
Solid Mechanics ◽  
Applied Pressure ◽  
Closed Form Expression ◽  
Nonlinear Relation ◽  
Set Up ◽  
Drop Flow

Fluid–structure interactions are ubiquitous in nature and technology. However, the systems are often so complex that numerical simulations or ad hoc assumptions must be used to gain insight into the details of the complex interactions between the fluid and solid mechanics. In this paper, we present experiments and theory on viscous flow in a simple bioinspired soft valve which illustrate essential features of interactions between hydrodynamic and elastic forces at low Reynolds numbers. The set-up comprises a sphere connected to a spring located inside a tapering cylindrical channel. The spring is aligned with the central axis of the channel and a pressure drop is applied across the sphere, thus forcing the liquid through the narrow gap between the sphere and the channel walls. The sphere’s equilibrium position is determined by a balance between spring and hydrodynamic forces. Since the gap thickness changes with the sphere’s position, the system has a pressure-dependent hydraulic resistance. This leads to a nonlinear relation between applied pressure and flow rate: flow initially increases with pressure, but decreases when the pressure exceeds a certain critical value as the gap closes. To rationalize these observations, we propose a mathematical model that reduced the complexity of the flow to a two-dimensional lubrication approximation. A closed-form expression for the pressure drop/flow rate is obtained which reveals that the flow rate $Q$ depends on the pressure drop $\unicode[STIX]{x0394}p$, sphere radius $a$, gap thickness $h_{0}$, and viscosity $\unicode[STIX]{x1D702}$ as $Q\sim \unicode[STIX]{x1D702}^{-1}a^{1/2}h_{0}^{5/2}(1-\unicode[STIX]{x0394}p/\unicode[STIX]{x0394}p_{c})^{5/2}\unicode[STIX]{x0394}p$, where the critical pressure $\unicode[STIX]{x0394}p_{c}$ scales with the spring constant $k$ as $\unicode[STIX]{x0394}p_{c}\sim kh_{0}a^{-2}$. These predictions compared favourably to the results of our experiments with no free parameters.

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