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Simultaneous 3D Lagrangian Particle Tracking of bubbles and fluid tracer particles in a bubbly water jet

Schröder, Andreas and Schanz, Daniel and Novara, Matteo and Kim, Dong and Seo, Hyundok and Kim, Youngwoo and Kim, Kyung Chun (2023) Simultaneous 3D Lagrangian Particle Tracking of bubbles and fluid tracer particles in a bubbly water jet. In: 15th International Symposium on Particle Image Velocimetry – ISPIV 2023 (243), pp. 1-2. The California State University (ScholarWorks). 15th International Symposium on Particle Image Velocimetry – ISPIV 2023, 18. -21. June 2023, San Diego, CA, USA.

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Official URL: https://scholarworks.calstate.edu/concern/publications/7s75dm11j


The experimental investigation of two-phase flows by means of particle-based optical field measurement techniques like PIV or Lagrangian Particle Tracking (LPT) pose significant challenges. Typically, the tracer particles within the fluid phase (e.g. water, air) are much smaller (Stokes numbers << 1), compared to the objects in the other phase (e.g. bubbles, solid particles, else). The illumination required to visualize the tracer particles therefore often significantly overexposes the larger objects, inhibiting a precise localization of both particle regimes. In such flows the grade of complexity for the particle position reconstruction and -tracking process even increases when applying 3D PIV or -LPT techniques using several camera projections. Two-phase turbulent flows are widely used in engineering and environmental applications (Balachandar & Eaton 1993; Mathai, Lohse & Sun 2020). This study describes a method for simultaneous measurements of time-resolved three-dimensional velocity and acceleration fields of the dispersed and continuous phases of a turbulent bubbly jet flow at a low void fraction using 3D LPT with the Shake-The-Box algorithm (Schanz et al. 2016, Schröder & Schanz 2023). Four high-speed cameras are used to acquire time series of images that include both bubbles and fluid tracer particles illuminated by a combination of two pulsed illumination sources with different intensities. A pulsed UV- LED array excites fluorescent tracer particles, which are imaged by four high-speed cameras using optical low-pass filters and a dimmer white-light LED array illuminates the bubbles (which are invisible for the cameras in the fluorescent light), leading to well exposed bubble and tracer images in the same image series. Bubbles are firstly tracked using intensity differences between tracer particles and bubbles, then the bubble images are removed from the camera images and all tracer particles are tracked using the residual images. Subsequently, FlowFit data assimilation (Gesemann et al. 2016) is applied to the obtained LPT results by phase separation to investigate the flow characteristics of the bubbly jet. This contribution is aiming at describing mainly the experimental set-up using two different LED arrays and fluorescent tracer particles and the image processing methods.

Item URL in elib:https://elib.dlr.de/195726/
Document Type:Conference or Workshop Item (Speech)
Additional Information:Contribution_243_final.pdf 2023-06-10 Public; http://hdl.handle.net/20.500.12680/7s75dm11j
Title:Simultaneous 3D Lagrangian Particle Tracking of bubbles and fluid tracer particles in a bubbly water jet
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Schröder, AndreasUNSPECIFIEDhttps://orcid.org/0000-0002-6971-9262138958724
Schanz, DanielUNSPECIFIEDhttps://orcid.org/0000-0003-1400-4224UNSPECIFIED
Novara, MatteoUNSPECIFIEDhttps://orcid.org/0000-0002-8975-0419UNSPECIFIED
Date:June 2023
Journal or Publication Title:15th International Symposium on Particle Image Velocimetry – ISPIV 2023
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:No
Page Range:pp. 1-2
Publisher:The California State University (ScholarWorks)
Series Name:Proceedings of the International Symposium on Particle Image Velocimetry
Keywords:Conference Track: Multiphase Flows, Shake-The-Box, 3D LPT, velocimetry and accelerometry, phase separation, turbulent bubbly jet
Event Title:15th International Symposium on Particle Image Velocimetry – ISPIV 2023
Event Location:San Diego, CA, USA
Event Type:international Conference
Event Dates:18. -21. June 2023
Organizer:San Diego State University
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Efficient Vehicle
DLR - Research area:Aeronautics
DLR - Program:L EV - Efficient Vehicle
DLR - Research theme (Project):L - Virtual Aircraft and  Validation
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Experimental Methods, GO
Deposited By: Micknaus, Ilka
Deposited On:19 Jul 2023 17:03
Last Modified:09 Aug 2023 14:56

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