scholarly journals Laminar flow past the bottom with obstacles – a suspension approximation

2015 ◽  
Vol 63 (3) ◽  
pp. 685-695
Author(s):  
R. Wojnar ◽  
W. Bielski
Keyword(s):  
Experimental Data ◽  
Spatial Distribution ◽  
Fluid Flow ◽  
Laminar Flow ◽  
Gravity Force ◽  
Fluid Viscosity ◽  
Suspension Concentration ◽  
Flow Past ◽  
Flow Through

Abstract From Albert Einstein’s study (1905) it is known that suspension introduced to a fluid modifies its viscosity. We propose to describe the influence of obstacles on the Stokesian flow as a such modification. Hence, we treat the fluid flow through small obstacles as a flow with suspension. The flow is developing past the plane bottom under the gravity force. The spatial distribution of suspension concentration is treated as given, and is regarded as an approximation of different obstacles which modify the fluid flow and change its viscosity. The different densities of suspension are considered, beginning of small suspension concentration until 40%. The influence of suspension concentration on fluid viscosity is analyzed, and Brinkman’s formula as fitting best to experimental data is applied.

Pore design and engineering for filters and membranes

2005 ◽  
Vol 364 (1838) ◽  
pp. 161-174 ◽  
Author(s):  
Richard Holdich ◽  
Serguei Kosvintsev ◽  
Iain Cumming ◽  
Sergey Zhdanov
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Pore Size ◽  
Suspended Material ◽  
Slot Length ◽  
Depth Filtration ◽  
Flow Through ◽  
Pore Flow ◽  
Modern Manufacturing ◽  
Manufacturing Techniques

In filtration, the concept of pore size is not easy to define. In microfiltration, there are numerous advantages in employing a surface filtering membrane, rather than one relying on depth filtration mechanisms from a tortuous pore flow channel. Modern manufacturing techniques provide means to produce surface filtering membranes. For filtration, it is shown that a suitable pore design is an array of long thin slots. An analysis of fluid flow through the slots suggests that a short slot is adequate, but experimental data with suspended material indicates that slot length is important. Using long slots and careful control of the flow through the membrane it is possible to filter deforming particles such as oil drops from water.

scholarly journals Numerical modeling of heat transfer in the fixed-matrix regenerator working in the Electric Thermal Storage heating system

2018 ◽  
Vol 240 ◽  
pp. 01008 ◽  
Author(s):  
Piotr Cisek ◽  
Dawid Taler ◽  
Grzegorz Cisek
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Flow Distribution ◽  
Thermal Storage ◽  
Heating System ◽  
Transfer Coefficients ◽  
Flow Through ◽  
Fixed Matrix

The study presents the concept of Electric Thermal Storage (ETS) central heating system. Thermal Energy Storage (TES) is carried out in the fixed-matrix regenerator. The energy conservation equations, determined for the discharge period of the regenerator operation, are implemented in MATLAB numerical procedures based on the Finite Volume Method (FVM). In the model pressure drops within the system are calculated, both for the airflow through the inner tubes, and between the tubes. The flow distribution calculations show that the assumption of even air flow distribution would not be justified. Subsequently, the values of heat transfer coefficients are determined for the four distinct heat transfer surfaces, for the variable axial coordinate z and during the time of the system operation. The use of two different criterion equations is considered, for determining the mean Nusselt number Num for fluid flow through the concentric annular duct, as well as for the local Nusselt number Nuz calculated for the fluid flow through a circular or non-circular ducts. The most appropriate approach is selected by comparing the calculation results with experimental data. Taking into account the relative error, RMSE, and MAPE values calculated, it may be concluded that the Taler correlation – for non-circular ducts – gives results closer to the experimental data obtained.

Laminar Fluid Flow in a Planar 90 Degree Bifurcation With and Without a Protruding Branching Duct

1996 ◽  
Vol 118 (1) ◽  
pp. 81-84 ◽  
Author(s):  
T. G. Travers ◽  
W. M. Worek
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Fluid Flow ◽  
Velocity Field ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Flow Field ◽  
Numerical Study ◽  
Main Duct

The laminar flow field in a planar, ninety degree bifurcation is examined. This numerical study uses the computational-fluid-dynamics software Fluent Version 4.11. First, the velocity field in a bifurcation without a protruding branching duct is modeled, and the results are successfully compared to experimental data. Next, the flow field is studied in bifurcations that have branching ducts that protrude into the main duct. The velocity field and pressure drop are documented, and are found to be strongly influenced by the extent of the branching duct protrusion.

Water Single-Phase Fluid Flow and Heat Transfer in Capillary Tubes

2003 ◽  
Author(s):  
A. Bucci ◽  
G. P. Celata ◽  
M. Cumo ◽  
E. Serra ◽  
G. Zummo
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Fluid Flow ◽  
Laminar Flow ◽  
Transfer Coefficient ◽  
Single Phase ◽  
Heat Transfer Correlations ◽  
Good Agreement

This paper reports the results of an experimental investigation of fluid flow and single-phase heat transfer of water in stainless steel capillary tubes. Three tube diameters are tested: 172 μm, 290 μm and 520 μm, while the Reynolds number varying from 200 up to 6000. Fluid flow experimental results indicate that in laminar flow regime the friction factor is in good agreement with the Hagen-Poiseuille theory for Reynolds number below 800–1000. For higher values of Reynolds number, experimental data depart from the Hagen-Poiseuille law to the side of higher f values. The transition from laminar to turbulent regime occurs for Reynolds number in the range 1800–3000. This transition is found in good agreement with the well known flow transition for rough commercial tubes. Heat transfer experiments show that heat transfer correlations in laminar and turbulent regimes, developed for conventional size tubes, are not adequate for calculation of heat transfer coefficient in microtubes. In laminar flow the experimental values of heat transfer coefficient are generally higher than those calculated with the classical correlation, while in turbulent flow regime experimental data do not deviate significantly from classical heat transfer correlations. Deviation from classical heat transfer correlations increase as the channel diameter decrease.

The Flow of a Perfect Fluid through Cascades of Aerofoils

1941 ◽  
Vol 45 (365) ◽  
pp. 183-213
Author(s):  
A. R. Collar
Keyword(s):  
Fluid Flow ◽  
Perfect Fluid ◽  
Conformal Transformation ◽  
Flow Past ◽  
Flow Through

SummaryThe paper contains a generalisation of the conformal transformation by means of which a circle is converted into Joukowski aerofoils. The transformation is applied to a cascade of oval bodies which is the corresponding generalisation of the isolated circle; and it converts the oval bodies into a wide variety of cascades of curved shapes, which are generalisations of the isolated Joukowski aerofoils. In one particular case, the transformation yields a grid of flat laminae. Since the perfect fluid flow through such a grid is known (it appears to have been first given by Joukowski) the perfect fluid flow past the ovals, in any direction, and with equal but otherwise arbitrary circulation round each, is obtained. Accordingly, the perfect fluid flow through any of the derived cascades can be obtained.

Steady and Unsteady Laminar Flow Past an Equilateral Triangular Cylinder for Two Different Orientations

2007 ◽  
Author(s):  
Zakir Faruquee ◽  
Temitope V. Olatunji
Keyword(s):  
Fluid Flow ◽  
Laminar Flow ◽  
Drag Coefficient ◽  
Incompressible Flow ◽  
Vortex Shedding ◽  
Equilateral Triangle ◽  
Downstream Side ◽  
Flow Past

Unconfined fluid flow past an equilateral triangle was numerically studied for laminar incompressible flow. Two configurations of the cylinder were studied. In the first configuration; a vertex was placed upstream and a side was placed in the downstream position normal to the flow, while in the second configuration; the orientation of the triangle was reversed, i.e. the side normal to the flow was placed upstream and a vertex was placed at the downstream. Both steady and unsteady simulations were performed at 30 ≤ Re ≤ 150. The results clearly show that the orientation of the triangle with the vertex at the downstream side stabilized the flow and delayed the onset of vortex shedding. Significant differences of drag coefficient, wake length, and velocity distributions were found between the two orientations of the equilateral triangle.

scholarly journals Review and a Theoretical Approach on Pressure Drop Correlations of Flow through Open-Cell Metal Foam

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3153
Author(s):  
Huizhu Yang ◽  
Yongyao Li ◽  
Binjian Ma ◽  
Yonggang Zhu
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Metal Foam ◽  
Flow Characteristics ◽  
Metal Foams ◽  
High Porosity ◽  
Open Cell ◽  
Wide Range ◽  
Flow Through

Due to their high porosity, high stiffness, light weight, large surface area-to-volume ratio, and excellent thermal properties, open-cell metal foams have been applied in a wide range of sectors and industries, including the energy, transportation, aviation, biomedical, and defense industries. Understanding the flow characteristics and pressure drop of the fluid flow in open-cell metal foams is critical for applying such materials in these scenarios. However, the state-of-the-art pressure drop correlations for open-cell foams show large deviations from experimental data. In this paper, the fundamental governing equations of fluid flow through open-cell metal foams and the determination of different foam geometry structures are first presented. A variety of published models for predicting the pressure drop through open-cell metal foams are then summarized and validated against experimental data. Finally, two empirical correlations of permeability are developed and recommended based on the model of Calmidi. Moreover, Calmidi’s model is proposed to calculate the Forchheimer coefficient. These three equations together allow calculating the pressure drop through open-cell metal foam as a function of porosity and pore diameter (or strut diameter) in a wide range of porosities ε = 85.7–97.8% and pore densities of 10–100 PPI. The findings of this study greatly advance our understanding of the flow characteristics through open-cell metal foam and provide important guidance for the design of open-cell metal foam materials for different engineering applications.

scholarly journals CFD study of heat transfer enhancement and fluid flow characteristics of laminar flow through tube with helical screw tape insert

2019 ◽  
Vol 160 ◽  
pp. 699-706 ◽  
Author(s):  
Mehedi Tusar ◽  
Kazi Ahmed ◽  
Muhammad Bhuiya ◽  
Palash Bhowmik ◽  
Mohammad Rasul ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Laminar Flow ◽  
Heat Transfer Enhancement ◽  
Flow Characteristics ◽  
Transfer Enhancement ◽  
Flow Through ◽  
Fluid Flow Characteristics
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