Oxygen Transport in Salmon Spawning Gravels

1980 ◽  
Vol 37 (2) ◽  
pp. 155-162 ◽  
Author(s):  
R. A. Johnson
Keyword(s):  
Oxygen Transport ◽  
Flow Resistance ◽  
Head Loss ◽  
Flow Through Porous Media ◽  
Air Entrapment ◽  
Flow Rates ◽  
Pressure Drops ◽  
Salmon Eggs ◽  
Flow Through ◽  
Media Data

The importance of understanding transport characteristics of flow through gravel media is discussed from the viewpoint of salmonid enhancement programs. A summary of the important features of the incubation process with respect to mass transport is provided along with applicable theories describing flow through porous media. Data obtained from experiments described herein are used to assess the accuracy of existing correlations for predicting pressure drops across gravel substrates. It is found that available hydraulic relations can be used to predict flow velocity magnitudes in gravel media with an accuracy of ± 50% over a twofold range of flow rates, providing one measurement of head loss is available at one flow rate. An adaptation of the Carman–Kozeny equation is found to be suitable for calculating the influence of fines on permeability. The importance of air entrapment on flow resistance is confirmed experimentally and modeled using available correlations. Lastly, the applications of these results for calculating oxygen transport to incubating salmon eggs and minimum water flows in hatcheries are discussed.Key words: Salmon enhancement, oxygen transport, permeability, gravel, incubation, hatcheries

Estimating the Coefficient of Inertial Resistance in Fluid Flow Through Porous Media

1974 ◽  
Vol 14 (05) ◽  
pp. 445-450 ◽  
Author(s):  
J. Geertsma
Keyword(s):  
Fluid Flow ◽  
Flow Resistance ◽  
Single Phase ◽  
Darcy’S Law ◽  
Darcy's Law ◽  
High Flow ◽  
Flow Through Porous Media ◽  
Flow Rates ◽  
Flow Through ◽  
Phase Fluid

Abstract The object of this paper is to introduce an empirical, time-honored relationship between inertia coefficient - frequently misnamed "turbulence factor" - permeability, and porosity, based on a combination of experimental data, dimensional analysis, and other physical considerations. The formula can be used effectively for, among other things, the preliminary evaluation of the number of wells in a new gas field and the spacing between them. Introduction It has long been recognized that Darcy's law for single-phase fluid flow through porous media,Equation 1 in which ?=superficial velocity µ=fluid viscosity k=formation permeability p=pressure head, is approximately correct only in a specific flow regime where the velocity ? is low. Single-phase fluid flow in reservoir rocks is often characterized by conditions in favor of this linearized flow law, but important exceptions do occur. They are in particular related to the surroundings of wells producing at high flow rates such as gas wells. For the prediction or analysis of the production behavior of such wells it is necessary to apply a more general nonlinear flow law. The appropriate formula was given in 1901 by Forchheimer1; it readsEquation 2 in which ?=density a=coefficient of viscous flow resistance 1/k ß=coefficient of inertial flow resistance. This equation indicates that in single-phase fluid flow through a porous medium two forces counteract the external force simultaneously - namely, viscous and inertial forces - the latter continuously gaining importance as the velocity ? increases. For low flow rates the viscous term dominates, whereas for high flow rates the inertia term does. The upper limit of practical applicability of Darcy's law can best be specified by some "critical value" orf the dimensionless ratio.Equation 3 which has a close resemblance to the Reynolds number. Observe that ß/a has the dimension of a length. Inertia and Turbulence As the Reynolds number is commonly used as an indicator for either laminar or turbulent flow conditions, the coefficient ß is often referred to as the turbulence coefficient. However, the phenomenon we are interested in has nothing to do with turbulence. The flow regime of concern is usually fully laminar. The observed departure from Darcy's law is the result of convective accelerations and decelerations of the fluid particles on their way through the pore space. Within the flow range normally experienced in oil and gas reservoirs, including the well's surroundings, energy losses caused by actual turbulence can be safely ignored.

Flow Resistance in Tracheotomy Tubes

1973 ◽  
Vol 82 (6) ◽  
pp. 827-830 ◽  
Author(s):  
John Cavo ◽  
Joseph H. Ogura ◽  
Donald G. Sessions ◽  
J. Roger Nelson
Keyword(s):  
Laminar Flow ◽  
Respiratory System ◽  
Flow Resistance ◽  
Airway Resistance ◽  
Upper Airway ◽  
Plastic Tube ◽  
Flow Rates ◽  
Pressure Drops ◽  
Adult Human

The role of the upper airway (the breathing passage above the trachea) in maintaining the normal junction of the respiratory system has been suggested by previous investigators. During a tracheotomy the upper airway is by-passed by a prosthetic metal or plastic tube which is placed into the trachea through the neck. In order to determine which, among the most commonly used tracheotomy tubes, most closely simulate the flow resistance of the adult human upper airway, a series of varying flow rates were passed through different sized tubes. Pressure drops were recorded and resistance values were thereby determined. Our data was compared with previously determined values for flow resistance of the adult human upper airway. Resistance related to turbulent and laminar flow was considered. On the basis of our data we have suggested that large caliber tracheotomy tubes be used in adult patients in whom the prolonged need for a tracheotomy is anticipated.

Friction Factor for Isothermal and Nonisothermal Flow Through Porous Media

1977 ◽  
Vol 99 (3) ◽  
pp. 367-373 ◽  
Author(s):  
J. C. Koh ◽  
J. L. Dutton ◽  
B. A. Benson ◽  
A. Fortini
Keyword(s):  
Reynolds Number ◽  
Porous Media ◽  
Friction Factor ◽  
Nonisothermal Flow ◽  
Flow Through Porous Media ◽  
Gaseous Flow ◽  
Pressure Drops ◽  
Flow Through ◽  
Temperature Levels ◽  
Nonisothermal Conditions

Measurements were performed to determine the pressure drops for gaseous flow through porous materials of different microstructures, porosities, and thickness under isothermal and nonisothermal conditions at various temperature levels. Results were satisfactorily correlated by a simple equation relating the friction factor to the Reynolds number and porosities.

scholarly journals Pipe Network Design and Analysis: An Example with WaterCAD

2021 ◽  
Author(s):  
Shiblu Sarker
Keyword(s):  
Water Systems ◽  
Water Utilities ◽  
Pipe Network ◽  
Flow Rates ◽  
Pressure Drops ◽  
Specialized Software ◽  
Hydraulic Design ◽  
Flow Through ◽  
The Common ◽  
The Individual

Pipe network analysis is the analysis of the fluid flow through a network that containing several interconnected branches of pipes and their components. The common analysis of pipe network often demonstrates to determine the flow rates and pressure drops in the individual components of the pipe network. Water utilities typically use specialized software to solve these issues automatically. Municipal water systems frequently route water through a water supply network to reach a large number of users. In this paper we aim to demonstrate the use of WaterCAD software to solve hydraulic design parameter of an example pipe network problem.

scholarly journals Simulation of the Flow Through Porous Layers Composed of Converging-Diverging Capillary Fissures or Tubes

2018 ◽  
Vol 23 (1) ◽  
pp. 161-185 ◽  
Author(s):  
A. Walicka
Keyword(s):  
Porous Medium ◽  
Power Law ◽  
Analytical Method ◽  
Algebraic Equations ◽  
Governing Equations ◽  
Flow Rates ◽  
Pressure Drops ◽  
Porous Layers ◽  
Linear Algebraic Equations ◽  
Flow Through

AbstractIn this paper, a porous medium is modelled by a network of converging-diverging capillaries which may be considered as fissures or tubes. This model makes it necessary to consider flows through capillary fissures or tubes. Therefore an analytical method for deriving the relationships between pressure drops, volumetric flow rates and velocities for the following fluids: Newtonian, polar, power-law, pseudoplastic (DeHaven and Sisko types) and Shulmanian, was developed. Next, considerations on the models of pore network for Newtonian and non-Newtonian fluids were presented. The models, similar to the schemes of central finite differences may provide a good basis for transforming the governing equations of a flow through the porous medium into a set of linear or quasi-linear algebraic equations. It was shown that the some coefficients in these algebraic equations depend on the kind of the capillary convergence.

scholarly journals Brownian Motion and Thermophoretic Effects in Mini Channels with Various Heights

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1965
Author(s):  
Zainab Al Hajaj ◽  
Mohamad Ziad Saghir
Keyword(s):  
Aspect Ratio ◽  
Heat Removal ◽  
Major Effect ◽  
Working Fluid ◽  
Flow Rates ◽  
Pressure Drops ◽  
Optimum Configuration ◽  
Mini Channels ◽  
Flow Through ◽  
The One

Flow-through mini channels have received tremendous interest from researchers over a long period. However, the study of flow between the channel and on top of the channel has received little to no attention. In the present paper, different parameters have been used to investigate this heat enhancement. The height of 10 mini channels has been varied, allowing the corresponding aspect ratio to vary from 3 to 6, 9, and 12. When the aspect ratio is 12, flow circulates through the mini channel only, and when the aspect ratio is less than 12, flow is distributed between the one circulating inside the channel and moving on top of the channel. Different flow rates are studied corresponding to a Reynolds number varying from 250 to 1250 if water is the working fluid. Brownian and thermophoresis effects are taken into consideration to investigate the nanoparticle sedimentation. Results revealed that the optimum configuration, if one needs to take into consideration the friction factor, is 12. If one ignores the pressure drops, then the optimum configuration is when the aspect ratio is equal to 6. This means that the flow interaction between the one circulating in the channel and above the channel plays a major effect in heat removal.

Creeping Flow Through Microchannels With Integrated Micro-Pillars

2012 ◽  
Author(s):  
Ali Tamayol ◽  
Naga S. K. Gunda ◽  
Mohsen Akbari ◽  
Sushanta K. Mitra ◽  
Majid Bahrami
Keyword(s):  
Pressure Drop ◽  
Flow Resistance ◽  
Creeping Flow ◽  
Geometrical Parameters ◽  
Flow Rates ◽  
Proposed Model ◽  
Pillar Diameter ◽  
Reverse Relationship ◽  
Flow Through ◽  
Micro Pillars

Pressure drop through micro-pillar-integrated mini/microchannels is studied experimentally and analytically. Following our previous studies, the low aspect ratio micropillars embedded in a microchannel are modeled as a porous medium sandwiched between channel walls. The pressure drop is expressed as a function of the salient geometrical parameters such as channel dimension, diameter and spacing between the adjacent cylinders as well as their arrangement. To verify the developed model, several silicon/glass samples with and without integrated pillars are fabricated using the deep reacting ion etching (DRIE) technique. Pressure drop measurements are performed over a range of water flow rates ranging from 0.1 ml/min to 0.5 ml/min. The proposed model is successfully verified with the present experimental data. A parametric study is performed by employing the proposed model, which shows that the flow resistance has a reverse relationship with the micro-pillar diameter and the mini/microchannel porosity. In addition, staggered arrangements have a significantly lower flow resistance than squared arrays of pillars especially in dense structures.

FRACTAL ANALYSIS OF FLOW RESISTANCE IN TREE-LIKE BRANCHING NETWORKS WITH ROUGHENED MICROCHANNELS

Fractals ◽  
2017 ◽  
Vol 25 (01) ◽  
pp. 1750008 ◽  
Author(s):  
SHANSHAN YANG ◽  
HUAHUA FU ◽  
BOMING YU
Keyword(s):  
Flow Resistance ◽  
Structural Parameters ◽  
Relative Increase ◽  
Average Height ◽  
Pressure Gradients ◽  
Pressure Drops ◽  
Relative Roughness ◽  
Branching Networks ◽  
Roughness Elements ◽  
Flow Through

In this work, the effective average height of the roughness elements, the relative increase of the pressure gradients, the relative decrease of the permeability are derived based on the fractal geometry theory and technique for laminar flow through tree-like branching networks with roughened channels. The relationships among the effective average height, the structural parameters and pressure drops as well as permeability are studied. It is found that the total pressure drop across a tree-like branching network with roughened channels is increased by a factor of [Formula: see text], and the permeability for the network with roughened channels is decreased by a factor of [Formula: see text], where [Formula: see text] is the relative roughness of surfaces of channels, compared to those with smooth channels.

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