PIV measurements of waves and turbulence in stratified horizontal two-phase pipe flow

2014 ◽  
Vol 62 ◽  
pp. 161-173 ◽  
Author(s):  
M. Birvalski ◽  
M.J. Tummers ◽  
R. Delfos ◽  
R.A.W.M. Henkes
Keyword(s):  
Pipe Flow ◽  
Two Phase ◽  
Piv Measurements

Kinematic and Dynamic Parameters of a Liquid-Solid Pipe Flow Using DPIV∕Accelerometry

2007 ◽  
Vol 129 (11) ◽  
pp. 1415-1421 ◽  
Author(s):  
Joseph Borowsky ◽  
Timothy Wei
Keyword(s):  
Pipe Flow ◽  
Solid Phase ◽  
Fluid Phase ◽  
Central Moment ◽  
Steady Flows ◽  
Dynamic Parameters ◽  
Two Phase ◽  
Turbulence Structures ◽  
Two Phases ◽  
Flat Profile

An experimental investigation of a two-phase pipe flow was undertaken to study kinematic and dynamic parameters of the fluid and solid phases. To accomplish this, a two-color digital particle image velocimetry and accelerometry (DPIV∕DPIA) methodology was used to measure velocity and acceleration fields of the fluid phase and solid phase simultaneously. The simultaneous, two-color DPIV∕DPIA measurements provided information on the changing characteristics of two-phase flow kinematic and dynamic quantities. Analysis of kinematic terms indicated that turbulence was suppressed due to the presence of the solid phase. Dynamic considerations focused on the second and third central moments of temporal acceleration for both phases. For the condition studied, the distribution across the tube of the second central moment of acceleration indicated a higher value for the solid phase than the fluid phase; both phases had increased values near the wall. The third central moment statistic of acceleration showed a variation between the two phases with the fluid phase having an oscillatory-type profile across the tube and the solid phase having a fairly flat profile. The differences in second and third central moment profiles between the two phases are attributed to the inertia of each particle type and its response to turbulence structures. Analysis of acceleration statistics provides another approach to characterize flow fields and gives some insight into the flow structures, even for steady flows.

Two Phase PIV Measurements at the Runner Outlet in a Francis Turbine

2003 ◽  
Author(s):  
Monica Sanda Iliescu ◽  
Gabriel Dan Ciocan ◽  
Franc¸ois Avellan
Keyword(s):  
Francis Turbine ◽  
Cavitation Flow ◽  
Two Phase ◽  
Piv Measurements ◽  
Turbine Runner ◽  
Physical Insight ◽  
Complex Phenomena ◽  
Hydro Turbines ◽  
Operating Regimes ◽  
Averaging Techniques

Part load operation of hydro turbines with fixed pitch blades causes complex instable cavitation flow in the diffuser cone. Application of PIV systems provides the opportunity to investigate the flow velocity and turbulent fields in the case of development of cavitation vortex, the so-called turbine rope, at the outlet of a Francis turbine runner. The synchronization of the PIV flow survey with the rope precession allows to apply phase averaging techniques in order to extract both the periodic velocity components and the rope layout. The influence of the turbine setting level on the volume of the cavity rope and its center is investigated, providing a physical insight on the hydrodynamic complex phenomena involved in the development of the cavitation rope at Francis turbine operating regimes.

PIV Measurements Within the Waves of Wavy and Wavy-Annular Horizontal Two-Phase Flow

2005 ◽  
Author(s):  
R. E. Foster ◽  
T. A. Shedd
Keyword(s):  
Particle Image ◽  
Image Processing Algorithm ◽  
Two Phase ◽  
Piv Measurements ◽  
Post Process ◽  
Image Velocimetry ◽  
Processed Form ◽  
Image Pairs ◽  
Particle Images ◽  
The Waves

A novel technique of microscopic Particle Image Velocimetry (PIV) is presented for two-phase annular, wavy-annular and stratified flow. Seeding of opaque particles in a water/dye flow allows the acquisition of instantaneous film velocity data in the film cross-section at the center of the tube in the form of digital image pairs. An image processing algorithm is also described that allows numerical velocities to be distilled from particle images by commercial PIV software. The approach yields promising results for stratified and wavy-annular flows, however highly bubbly flows remain difficult to image and post-process. Initial data images are presented in raw and processed form.

A hybrid phase boundary detection technique for two-phase-flow PIV measurements

2020 ◽  
Vol 74 ◽  
pp. 101776
Author(s):  
F. Gökhan Ergin ◽  
Jimmy Olofsson ◽  
Per Petersson ◽  
Nicolai Fog Gade-Nielsen
Keyword(s):  
Phase Boundary ◽  
Two Phase Flow ◽  
Boundary Detection ◽  
Detection Technique ◽  
Phase Flow ◽  
Two Phase ◽  
Piv Measurements

Unified Model for Gas-Liquid Pipe Flow Via Slug Dynamics: Part 1 — Model Development

2002 ◽  
Author(s):  
Hong-Quan Zhang ◽  
Qian Wang ◽  
Cem Sarica ◽  
James P. Brill
Keyword(s):  
Flow Pattern ◽  
Pipe Flow ◽  
Slug Flow ◽  
Control Volume ◽  
Model Development ◽  
Flow Patterns ◽  
Hydrodynamic Characteristics ◽  
Momentum Exchange ◽  
Two Phase ◽  
Inclination Angles

A unified hydrodynamic model is developed for predictions of flow pattern transitions, pressure gradient, liquid holdup and slug characteristics in gas-liquid pipe flow at different inclination angles from −90 to 90 deg. The model is based on the dynamics of slug flow, which shares transition boundaries with all the other flow patterns. By use of the entire film zone as the control volume, the momentum exchange between the slug body and the film zone is introduced into the momentum equations for slug flow. The equations of slug flow are used not only to calculate the slug characteristics, but also to predict transitions from slug flow to other flow patterns. Significant effort has been made to eliminate discontinuities among the closure relationships through careful selection and generalization. The flow pattern classification is also simplified according to the hydrodynamic characteristics of two-phase flow.

Three-Dimensional Bubble Reconstruction in a Pipe Flow Using Shadow Technique

2002 ◽  
Author(s):  
Javier Ortiz-Villafuerte ◽  
Yassin A. Hassan ◽  
Toru Furukawa
Keyword(s):  
Pipe Flow ◽  
Particle Image ◽  
Three Dimensional ◽  
Bubbly Flows ◽  
Three Dimensional Reconstruction ◽  
Two Phase ◽  
Generalized Hough Transform ◽  
Image Velocimetry ◽  
Dimensional Reconstruction ◽  
Shadow Image Velocimetry

Two different three-dimensional reconstruction techniques for the shape of gas bubbles flowing in a liquid are presented. The first technique is based on the Dynamic Generalized Hough Transform Algorithm, and the second on the Metaball Model. These techniques are suitable for analysis of turbulent two-phase bubbly flows. Both techniques require at least two views of the bubble intended for three-dimensional reconstruction, and can be used in either stereoscopic or orthogonal camera setups. Once the reconstruction is accomplished, the bubble images can be accurately removed from the images acquired during Particle Image Velocimtery or Shadow Image Velocimetry measurements. After removing the bubble images from PIV images, a typical analysis of the liquid phase can be performed. This improves the accuracy of the statistical analysis of the parameters of each phase.

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