Excess Pressure Drop in Laminar Flow through Sudden Contraction. Newtonian Liquids

1968 ◽  
Vol 7 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Gianni Astarita ◽  
Guido Greco
Keyword(s):  
Pressure Drop ◽  
Laminar Flow ◽  
Excess Pressure ◽  
Sudden Contraction ◽  
Flow Through ◽  
Newtonian Liquids

Creeping Flow Through an Axisymmetric Sudden Contraction or Expansion

2001 ◽  
Vol 124 (1) ◽  
pp. 273-278 ◽  
Author(s):  
Sourith Sisavath ◽  
Xudong Jing ◽  
Chris C. Pain ◽  
Robert W. Zimmerman
Keyword(s):  
Pressure Drop ◽  
Expansion Ratio ◽  
Excess Pressure ◽  
Creeping Flow ◽  
Numerical Studies ◽  
Equivalent Length ◽  
Sudden Contraction ◽  
Circular Orifice ◽  
Flow Through ◽  
Infinite Wall

Creeping flow through a sudden contraction/expansion in an axisymmetric pipe is studied. Sampson’s solution for flow through a circular orifice in an infinite wall is used to derive an approximation for the excess pressure drop due to a sudden contraction/expansion in a pipe with a finite expansion ratio. The accuracy of this approximation obtained is verified by comparing its results to finite-element simulations and other previous numerical studies. The result can also be extended to a thin annular obstacle in a circular pipe. The “equivalent length” corresponding to the excess pressure drop is found to be barely half the radius of the smaller tube.

scholarly journals Variation of Pressure Drop along the Straight and Bifurcated Channel: Experiment and Simulation

2019 ◽  
Vol 8 (12) ◽  
pp. 2728-2731
Keyword(s):  
Pressure Drop ◽  
Laminar Flow ◽  
Aspect Ratio ◽  
Computational Model ◽  
Flow Rate ◽  
Normal Water ◽  
Flow Through ◽  
Experiment And Simulation

This paper derives an experimental and simulated investigation carried to analyze the performance of channel for calculating the pressure drop in laminar flow through rectangular shaped (straight and branched) microchannels. The microchannels taken ranged in variable aspect ratio from 0.75 to 1. Every check piece was made from copper and contained only one channel along a direction. The experiments were conducted with normal water, with Reynolds range starting from some 720 to 3500. Predictions obtained supported that with the variation in the aspect ratio the properties of the fluid also change. It is observed that the pressure drop changes with the change in the aspect ratio and flow rate and found that there is a correlation between the experimental and computational model results.

Predicting the excess pressure drop incurred by LPTT fluids in flow through a planar constricted channel

2019 ◽  
Vol 31 (3) ◽  
pp. 149-166
Author(s):  
Taha Rezaee ◽  
Mostafa Esmaeili ◽  
Solmaz Bazargan ◽  
Kayvan Sadeghy
Keyword(s):  
Pressure Drop ◽  
Excess Pressure ◽  
Flow Through ◽  
Constricted Channel

Steady laminar flow of blood through successive restrictions in circular conduits of small diameter

2008 ◽  
Vol 222 (8) ◽  
pp. 1557-1573 ◽  
Author(s):  
D Nag ◽  
A Datta
Keyword(s):  
Blood Flow ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Small Diameter ◽  
Rigid Wall ◽  
Pressure Loss Coefficient ◽  
Axial Velocity Distribution ◽  
Recirculation Zones ◽  
Flow Through ◽  
Steady Laminar

In this paper, numerical results on steady laminar flow of blood through an artery having two successive identical axisymmetric restrictions are presented, at varying degrees of restrictions. Physically, such a flow has features in common with steady blood flow through an artery with multiple stenoses. Additionally, results are presented for the blood flow through an artery in the presence of a single restriction, for comparison. The artery has been modelled as a tube with a rigid wall. The rheological characteristics of blood have been assumed both as Newtonian and non-Newtonian. Three different non-Newtonian models of blood — power law, Quemada, and Carreau—Yasuda models — have been considered in the analysis. The haemodynamic effects of the restrictions on the axial velocity distribution, recirculation zones formed downstream to the restrictions, the wall shear stress, and the pressure drop in the artery have been analysed. The irreversible pressure loss coefficient is calculated from the pressure drop and its variation with the degree of stenosis is obtained.

scholarly journals EXPERIMENTAL STUDY OF THE FLOW DYNAMICS OF COMPLEX VISCOELASTIC FLUID THROUGH HYPERBOLIC CONTRACTION/EXPANSION

2020 ◽  
pp. 76-94
Author(s):  
Muñoz Garduño Kevin David ◽  
Pérez Camacho Mariano
Keyword(s):  
Pressure Drop ◽  
Shear Flow ◽  
Extensional Flow ◽  
Viscoelastic Fluids ◽  
Excess Pressure ◽  
Flow Dynamics ◽  
Shear Type ◽  
Flow Through ◽  
Expansion System ◽  
Hyperbolic Contraction

The main objetive of this work was to experimentally study the Flow dynamics of viscoelastic fluids (Boger fluid and Hase) when they flow through a contraction/expansion system defined by a hyperbolic tube, therefore through equations analogous to the Hagen-Poiseuille equation, the pressure drop associated with the viscous interaction was quantified, and subsequently the excess pressure drop (EPD), a parameter associated with the elasticity of viscoelastic fluids, conducting comparative studies with respect to a Newtonian reference for the same shear viscosity value, which allowed observing shear speed intervals where three predominant zones were observed. The first of them of shear type coinciding with the trajectories of the Newtonian fluid of identical viscosity value, the second zone was attributed to the elastic manifestation of the fluids due to the preferential development of the extensional flow that is in constant competition with the shear flow within of the same geometry. The third zone was attributed to a predominance of the shear flow over the extensional one, because of to the fact that the hyperbolic geometry favors the development of this type of flow at high values of shear rate KEYWORDS: Excess pressure drop; Extensional flow; Hyperbolic contractions

An Analysis of Laminar Flow and Pressure Drop in Complex Shaped Ducts

1976 ◽  
Vol 98 (4) ◽  
pp. 702-706 ◽  
Author(s):  
John P. Zarling
Keyword(s):  
Pressure Drop ◽  
Laminar Flow ◽  
Cross Section ◽  
Flow Rate ◽  
Series Solution ◽  
Complex Geometry ◽  
Constant Cross Section ◽  
Point Matching ◽  
Friction Factors ◽  
Flow Through

An analytical method is presented for solving the governing equation for fully developed, steady, incompressible laminar flow through ducts of constant cross-section having a complex geometry. The technique uses the Schwarz-Neumann alternating method along with least squares point matching. The method is applied to a complex shaped duct and the resulting velocity series solution is used to calculate the flow rate and pressure drop (f•Re) for a range of duct sizes. Numerical results are presented and compared with experimentally determined friction factors for a duct of similar geometry.

Relationship Between Pressure Drop and Heat Transfer of Fully Developed Flow in Smooth Horizontal Circular Tubes and Spiral Coiled Tubes in the Laminar Flow Regime

2021 ◽  
Author(s):  
Rahul H Patil ◽  
Mandar V Tendolkar
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Flow Regime ◽  
Length Ratio ◽  
Dimensionless Group ◽  
Laminar Flow Regime ◽  
Friction Factors ◽  
Flow Through ◽  
Spiral Coils

Abstract Studies on isothermal steady state frictional pressure drop for flow of petroleum base oil SN70, SN150, Diesel and water are carried out in spiral coils with diameter to length ratio, 0.00042, 0.00047, 0.00073, 0.00164, 0.00189, 0.003 and 0.0037. An attempt is made to correlate friction factors with a better and more appropriate dimensionless group for flow of Newtonian fluids through spiral coiled tubes. An innovative approach of correlating heat transfer data with the newly established dimensionless group is presented. Heat transfer experiments are performed for spiral coils with diameter to length ratio 0.000474, 0.00042, 0.001896, 0.00198, 0.000942, 0.00164 in laminar flow regime. Suitable correlations for friction factors and Nusselt numbers are proposed. Relationship between pressure drop and heat transfer is studied. The incapability of the conventional analogy equations to estimate the heat and momentum transfer coefficients for laminar flow through straight or curved tubes is explained based on the viscous and form drag existing in straight and curved pipe flow. The limitations of the existing analogy equations are examined critically. A new general analogy equation is derived for laminar flow through spiral and straight tubes considering the influencing geometrical parameters of the tube. Keywords: Forced Convection; Heat and Mass transfer; Heat Exchangers; Thermal Systems.

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