scholarly journals Transient Behavior of Vortical Flow through a Constant Diameter Pipe

2001 ◽  
Vol 13 (9) ◽  
pp. S8-S8 ◽  
Author(s):  
T. W. Mattner ◽  
M. S. Chong ◽  
P. N. Joubert
Keyword(s):  
Transient Behavior ◽  
Vortical Flow ◽  
Constant Diameter ◽  
Diameter Pipe ◽  
Flow Through

scholarly journals Vortical flow. Part 1. Flow through a constant-diameter pipe

2002 ◽  
Vol 463 ◽  
pp. 259-291 ◽  
Author(s):  
T. W. MATTNER ◽  
P. N. JOUBERT ◽  
M. S. CHONG
Keyword(s):  
Axial Velocity ◽  
Test Section ◽  
Velocity Profiles ◽  
Vortical Flow ◽  
Outer Flow ◽  
Spiral Vortex ◽  
Constant Diameter ◽  
Diameter Pipe ◽  
Flow Through ◽  
Streamwise Distance

This paper describes an exploration of the behaviour and properties of swirling flow through a constant-diameter pipe. The experiments reveal a complicated transition process as the swirl intensity Ω is increased at fixed pipe Reynolds number Re ≈ 4900. For Ω [les ] 1.09, the vortex was steady, laminar, axisymmetric, and developed slowly with streamwise distance. The upstream velocity profiles were similar to those commonly appearing in the literature in similar apparatus. Spiral vortex breakdown appeared in the test section for 1.09 [les ] Ω [les ] 1.31 and was associated with a localized transition from jet-like to wake-like mean axial velocity profiles. Further increase in Ω caused the breakdown to move upstream of the test section. Downstream, the core of the post-breakdown flow was unsteady and recovered toward jet-like profiles with streamwise distance. At Ω = 2.68, a global transition occurred in which the mean axial velocity profiles suddenly developed an annular axial velocity deficit. At the same time, disturbances began to appear in the outer flow. Further increase in Ω eventually led to an annulus of reversed axial flow and a completely unsteady vortex.

scholarly journals Vortical flow. Part 2. Flow past a sphere in a constant-diameter pipe

2003 ◽  
Vol 481 ◽  
pp. 1-36 ◽  
Author(s):  
T. W. MATTNER ◽  
P. N. JOUBERT ◽  
M. S. CHONG
Keyword(s):  
Vortical Flow ◽  
Flow Past ◽  
Constant Diameter ◽  
Diameter Pipe ◽  
Flow Part ◽  
Flow Past A Sphere

Transient behavior of supersonic flow through inlets

1990 ◽  
Author(s):  
H. PORDAL ◽  
P. KHOSLA ◽  
S. RUBIN
Keyword(s):  
Supersonic Flow ◽  
Transient Behavior ◽  
Flow Through

An Investigation of Resonance Conditions for Pulsating Flow of Air through an Orifice in a Pipe

1973 ◽  
Vol 6 (1) ◽  
pp. 41-46
Author(s):  
B W Imrie ◽  
R A Evans†
Keyword(s):  
Acoustic Waves ◽  
Gas Flow ◽  
Pulsating Flow ◽  
Dimensional Parameter ◽  
Inertia Effects ◽  
Diameter Pipe ◽  
Dependent Variables ◽  
Mass Flow Rates ◽  
Flow Through ◽  
Variable Analysis

A review of some previous studies of pulsating air flow through orifices in pipes is presented. In particular, the authors comment on the significance of inertia effects, the use of Strouhal number as a non-dimensional parameter, and the effect of phase change on time-dependent variables. Attention is drawn to the possible importance of the previously neglected interaction between the effects of orifices as acoustical filters and as meters of pulsating flow. Using complex variable analysis, a theoretical model based on plane acoustic waves yields, for resonance conditions, relationships between frequency, pressure and geometry variables. These were investigated experimentally for a 1-in diameter pipe with different orifice diameters for a range of frequencies up to 180 Hz. The results indicate that accurate derivation of mass flow rates from pressure measurements across an orifice in a pipe depends on taking into account the effects of wave action at all frequencies. This would avoid the rig-dependent limitations to which experimental work on pulsating gas flow through an orifice in a pipe is subject.

The Transient Response of Orifices and Very Short Lines

1972 ◽  
Vol 94 (2) ◽  
pp. 483-489 ◽  
Author(s):  
J. E. Funk ◽  
D. J. Wood ◽  
S. P. Chao
Keyword(s):  
Steady State ◽  
Pressure Drop ◽  
System Analysis ◽  
Transient Flow ◽  
Transient Behavior ◽  
Short Term ◽  
State Equations ◽  
Steady State Condition ◽  
Orifice Flow ◽  
Flow Through

It is generally assumed that orifices and valves follow closely their steady-state characteristics during transient operation. However, this assumption of quasisteady behavior may lead to errors in predicting transient flow conditions under certain circumstances. In order to evaluate the transient behavior of an orifice, a differential equation relating the flow through and the pressure drop across an orifice was derived. An extension was made to include an axial dimension for the orifice. The solution of this equation for transient flow through an orifice subjected to a step change in pressure drop across the orifice is significantly different than that obtained using the steady state relationship. An experiment was designed to evaluate the theoretical results in which an orifice on the end of a line was subjected to a sudden pressure change and the resulting transient pressures were observed. It was found that a significant short term transient occurs before the orifice flow reaches the new steady state condition. The observed short term transient agrees well with that predicted by the theory. It is concluded that the behavior of an orifice can deviate considerably from that predicted by steady-state equations during periods of rapid pressure or flow changes. The dynamic description of orifice flow may be combined with a larger system analysis (e.g., using the method of characteristics) to more accurately predict the overall transient performance of flow systems.

Transient behavior of supersonic flow through inlets

AIAA Journal ◽  
1992 ◽  
Vol 30 (3) ◽  
pp. 711-717 ◽  
Author(s):  
H. S. Pordal ◽  
P. K. Khosla ◽  
S. G. Rubin
Keyword(s):  
Supersonic Flow ◽  
Transient Behavior ◽  
Flow Through

scholarly journals CFD Analysis of Non-Newtonian Pseudo Plastic Liquid Flow through Bends

2017 ◽  
Vol 61 (3) ◽  
pp. 184 ◽  
Author(s):  
Suman Debnath ◽  
Tarun Kanti Bandyopadhyay ◽  
Apu Kumar Saha
Keyword(s):  
Pressure Drop ◽  
Liquid Flow ◽  
Static Pressure ◽  
Methyl Cellulose ◽  
Bend Angle ◽  
Frictional Pressure Drop ◽  
Fluid Behavior ◽  
Diameter Pipe ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through

Non-Newtonian pseudo plastic liquid flow through different types of 0.0127 m diameter pipe bends as well as straight pipe have been investigated experimentally to evaluate frictional pressure drop across the bends in laminar and water flow in turbulent condition. We have studied here the effect of flow rate, bend angle, fluid behavior on static pressure and pressure drop. A Computational Fluid Dynamics (CFD) based software is used to predict the static pressure, pressure drop, shear stress, shear strain, flow structure, friction factor, loss co- efficient inside the bends for Sodium Carboxy Methyl Cellulose (SCMC) solution as a non-Newtonian pseudo plastic fluids and water as a Newtonian fluid. Laminar Non-Newtonian pseudo plastic Power law model is used for SCMC solution to numerically solve the continuity and the momentum equations. The experimental data are compared with the CFD generated data and is well matched. The software predicted data may be used to solve any industrial problem and also to design various equipment.

A New Emergency Stop and Control Valve Design: Part 2 — Validation of Numerical Model and Transient Flow Physics

2014 ◽  
Author(s):  
Christian Musch ◽  
Frank Deister ◽  
Gerta Zimmer ◽  
Ingo Balkowski ◽  
Peter Brüggemann ◽  
...  
Keyword(s):  
Steady State ◽  
Mass Flow ◽  
Transient Flow ◽  
Control Valve ◽  
Transient Behavior ◽  
Complex Flow ◽  
Stop Valve ◽  
Turbine Inlet ◽  
Flow Through ◽  
Emergency Stop

In order to enhance steam mass flow through a turbine it becomes necessary to reduce the flow resistance of the turbine inlet valves. Consequently, a replacement of the high pressure turbine inlet valves is required. The valve combination described in this paper consists of a control valve and an emergency stop valve, opposite to the control valve. Both valves share a common valve seat. The control valve is a single-seat valve with integral pilot disc. A pre-stoke is introduced to allow for moderate opening forces. The emergency stop valve closes in countercurrent with the steam mass flow. The flow through the valve is analyzed by steady state and transient computational flow simulations. In addition to the steam mass flow, the forces acting upon the valve are determined. Transient behavior will be investigated by means of analyzing pressure fluctuations. Therefore frequencies caused by the steam flow are determined in the range up to 2000Hz. It will be shown that neither steady state nor transient simulations with a simple eddy viscosity turbulence model are capable to correctly predict the complex flow inside the valve. More sophisticated turbulence modeling like Large-Eddy simulation is thus inevitable. Furthermore, the physical phenomena causing the transient behavior are discussed. All findings are verified by comparison of the CFD with the measurements.

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