Analysis of vortex core generation in pipe flows under different Reynolds number conditions

2021 ◽  
Vol 43 (6) ◽  
Author(s):  
F. J. Salvador ◽  
M. Carreres ◽  
P. Quintero ◽  
L. A. González-Montero
Keyword(s):  
Reynolds Number ◽  
Vortex Core ◽  
Pipe Flows

Numerical Study of Convective Heat Transfer From Expanding Annular Pipe Flows

2016 ◽  
Author(s):  
Khaled J. Hammad
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Prandtl Number ◽  
Convective Heat Transfer ◽  
Diameter Ratio ◽  
Wall Heat Transfer ◽  
Reattachment Point ◽  
Transfer Rates ◽  
Pipe Flows ◽  
Annular Pipe

Convective heat transfer from suddenly expanding annular pipe flows are numerically investigated within the steady laminar flow regime. A parametric study is performed to reveal the influence of the annular diameter ratio, k, the Prandtl number, Pr, and the Reynolds number, Re, over the following range of parameters: k = {0, 0.5, 0.7}, Pr = {0.7, 1, 7, 100}, and Re = {25, 50, 100}. Heat transfer enhancement downstream of the expansion plane is only observed for Pr > 1. Peak wall-heat-transfer-rates always appear downstream of the flow reattachment point, in the case of suddenly expanding round pipe flows, i.e. k = 0. However, for suddenly expanding annular pipe flows, i.e., k = 0.5 and 0.7, peak wall-heat-transfer-rates always appear upstream of the flow reattachment point. The observed heat transfer augmentation is more dramatic for suddenly expanding annular flows, in comparison with the one observed for suddenly expanding pipe flows. For a given annular diameter ratio and Reynolds number, increasing the Prandtl number, always results in higher wall-heat-transfer-rates downstream the expansion plane.

Measurements of the Tip Clearance Flow for a High-Reynolds-Number Axial-Flow Rotor

1995 ◽  
Vol 117 (4) ◽  
pp. 522-532 ◽  
Author(s):  
W. C. Zierke ◽  
K. J. Farrell ◽  
W. A. Straka
Keyword(s):  
Reynolds Number ◽  
Flow Visualization ◽  
Vortex Core ◽  
Rotor Blade ◽  
High Reynolds Number ◽  
Tip Clearance ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Blade Tip ◽  
High Reynolds

A high-Reynolds-number pump (HIREP) facility has been used to acquire flow measurements in the rotor blade tip clearance region, with blade chord Reynolds numbers of 3,900,000 and 5,500,000. The initial experiment involved rotor blades with varying tip clearances, while a second experiment involved a more detailed investigation of a rotor blade row with a single tip clearance. The flow visualization on the blade surface and within the flow field indicate the existence of a trailing-edge separation vortex, a vortex that migrates radially upward along the trailing edge and then turns in the circumferential direction near the casing, moving in the opposite direction of blade rotation. Flow visualization also helps in establishing the trajectory of the tip leakage vortex core and shows the unsteadiness of the vortex. Detailed measurements show the effects of tip clearance size and downstream distance on the structure of the rotor tip leakage vortex. The character of the velocity profile along the vortex core changes from a jetlike profile to a wakelike profile as the tip clearance becomes smaller. Also, for small clearances, the presence and proximity of the casing endwall affects the roll-up, shape, dissipation, and unsteadiness of the tip leakage vortex. Measurements also show how much circulation is retained by the blade tip and how much is shed into the vortex, a vortex associated with high losses.

Experimental evaluation of the mean momentum and kinetic energy balance equations in turbulent pipe flows at high Reynolds number

2019 ◽  
Vol 20 (5) ◽  
pp. 285-299 ◽  
Author(s):  
El-Sayed Zanoun ◽  
Christoph Egbers ◽  
Ramis Örlü ◽  
Tommaso Fiorini ◽  
Gabriele Bellani ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Energy Balance ◽  
Kinetic Energy ◽  
Experimental Evaluation ◽  
High Reynolds Number ◽  
Balance Equations ◽  
Pipe Flows ◽  
The Mean ◽  
High Reynolds

Hydraulic Behaviour of Nuclear Waste Flows

2009 ◽  
Author(s):  
S. R. Biggs ◽  
M. Fairweather ◽  
D. Harbottle ◽  
B. Lin ◽  
J. Peakall
Keyword(s):  
Reynolds Number ◽  
Nuclear Waste ◽  
Waste Treatment ◽  
Reynolds Numbers ◽  
Nuclear Industry ◽  
Doppler Velocity ◽  
Successful Implementation ◽  
Pipe Flows ◽  
Solids Concentration ◽  
Solid Liquid

A great deal of existing nuclear waste is stored as a solid-liquid slurry, and the effective transportation of such systems is an essential element in the successful implementation of almost all waste treatment strategies involving particulate wastes within the nuclear industry. A detailed knowledge of turbulent, particle-laden liquid flow behaviour is therefore obviously important. However, systematic and detailed studies of solid-liquid flows by experimental investigation are still limited for pipe flows, contrary to the significant amount of work available for channel flows. Research is therefore required to understand the effects of physical parameters, such as particle shape, size and size distribution, and solids concentration, on the properties of solid-liquid systems, particularly in horizontal pipe flows where particles may settle out of the flow and form solid beds which can potentially lead to pipe blockages. The presence of particles in a turbulent pipe flow also modifies the characteristics of the flow, thereby changing its ability to maintain particles in suspension. The work described concerns pipe flows over a Reynolds number range of 1,000–10,000, with varying levels of solids concentration within the flow. Measurements of the flow and particle characteristics have been gathered using particle image velocimetry (PIV) and, for high solids concentrations, ultrasound Doppler velocity profiling (UDVP) techniques. This work has demonstrated that the intensity of turbulence within such flows can be significantly affected by the presence of solid particles, with small particles generally attenuating turbulence levels, while large particles often augment turbulence levels from the pipe centre-line to the near-wall region. In addition, the coagulation of particles into larger agglomerates is also of importance, with data demonstrating that whilst turbulence levels are influenced and augmented by such agglomerates at low Reynolds numbers, high turbulence levels at high Reynolds numbers can destroy the agglomerates and reduce their effect on the carrier fluid. Work has also been undertaken to examine the effect of particle size and Reynolds number on particle deposition within the flows, and also to establish the minimum transport velocity required to re-suspend particles from solid beds. All these findings are of importance in enhancing our understanding of flows of particles in pipes which in turn is of value in enabling the design of cost effective and efficient waste treatment processes.

scholarly journals Electron Spin-Vorticity Coupling in Pipe Flows at Low and High Reynolds Number

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Hamid Tabaei Kazerooni ◽  
Alexander Thieme ◽  
Jörg Schumacher ◽  
Christian Cierpka
Keyword(s):  
Reynolds Number ◽  
Electron Spin ◽  
High Reynolds Number ◽  
Pipe Flows ◽  
High Reynolds

Highly viscous liquid flow in pipeline components

2005 ◽  
Vol 219 (3) ◽  
pp. 267-281 ◽  
Author(s):  
D A McNeil ◽  
A D Stuart
Keyword(s):  
Reynolds Number ◽  
Viscous Liquid ◽  
Liquid Flow ◽  
Flow Behaviour ◽  
Number Range ◽  
Pipe Flows ◽  
Discharge Coefficients ◽  
Friction Factors ◽  
Loss Coefficients ◽  
Globe Valve

Water and an aqueous glycerine solution were used to obtain liquids with nominal viscosities of 1 and 550 mPa s. These fluids were used to obtain friction factors for pipe flows, discharge coefficients for orifice plates and nozzles, and loss coefficients for an abrupt enlargement, a nozzle, an orifice plate, and a globe valve in the Reynolds number range 10-200. Existing methods are shown to be adequate for the prediction of friction factors and discharge coefficients, but inadequate for the prediction of loss coefficients. Insight is given into the flow behaviour that is associated with the loss coefficients.

scholarly journals Numerical study of upward particulate pipe flows at a constant Reynolds number

2012 ◽  
Vol 62 (2) ◽  
pp. 97
Author(s):  
A Kartushinsky ◽  
Y Rudi ◽  
S Tisler ◽  
I Shcheglov ◽  
A Shablinsky
Keyword(s):  
Reynolds Number ◽  
Numerical Study ◽  
Pipe Flows

Analytical Solution for Newtonian Laminar Flow Through the Concave and Convex Ducts

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
M. Firouzi ◽  
S. H. Hashemabadi
Keyword(s):  
Reynolds Number ◽  
Steady State ◽  
Friction Factor ◽  
Cross Section ◽  
Cross Sections ◽  
Fully Developed Flow ◽  
Pipe Flows ◽  
Dimensionless Velocity ◽  
Flow Through ◽  
Fanning Friction Factor

In this paper, the motion equation for steady state, laminar, fully developed flow of Newtonian fluid through the concave and convex ducts has been solved both numerically and analytically. These cross sections can be formed due to the sedimentation of heavy components such as sand, wax, debris, and corrosion products in pipe flows. The influence of duct cross section on dimensionless velocity profile, dimensionless pressure drop, and friction factor has been reported. Finally based on the analytical solutions three new correlations have been proposed for the product of Reynolds number and Fanning friction factor (Cf Re) for these geometries.

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