Data publication: Measurement of liquid foam flow through a diverging nozzle

2026-06-05T01:58:37Z https://rodare.hzdr.de/oai2d

oai:rodare.hzdr.de:3624 2025-07-16T06:56:57Z openaire_data user-fwd user-rodare user-hzdr

true 3.1 HZDR.RODARE 10.14278/rodare.3624 Skrypnik, Artem 0000-0002-3472-3421 Lappan, Tobias 0000-0003-2826-1395 Knüpfer, Leon 0000-0001-7012-7662 Ziauddin, Muhammad 0000-0002-4580-9482 Arnal Tribaldos, Icíar 0009-0008-1824-5037 Shevchenko, Natalia 0000-0002-6177-2130 Heitkam, Sascha 0000-0002-2493-7629 Data publication: Measurement of liquid foam flow through a diverging nozzle Rodare 2025 Drainage Liquid fraction Particle tracking velocimetry Particle image velocimetry Pneumatic foam theory X-ray radiography 2025-03-07 en https://rodare.hzdr.de/record/3624 https://www.hzdr.de/publications/Publ-41083 https://www.hzdr.de/publications/Publ-41024 10.14278/rodare.3623 https://rodare.hzdr.de/communities/fwd https://rodare.hzdr.de/communities/hzdr https://rodare.hzdr.de/communities/rodare Creative Commons Attribution 4.0 International Open Access The hydrodynamic theory of pneumatic foam analytically predicts the advective transport of liquid by foam rising continuously in a vertical column or pipe, relying on cross-sectional averaging of the foam velocity and liquid fraction. This experimental study accumulates a database for assessing the pneumatic foam theory in a vertically aligned diverging nozzle, i.e. at increasing cross-sectional area in nominal flow direction. The velocity distribution of the flowing foam and its liquid fraction distribution were measured by means of X-ray, optical and electrical techniques in three different nozzles distinguished by their half angle θ = 5°, 10°, 20°. The experimental setup and the measurements are described in detail in Skrypnik et al. (<a href="https://www.hzdr.de/publications/Publ-41024">https://www.hzdr.de/publications/Publ-41024</a>). <ul> <li>X-ray radiography (XR) has measured the distribution of the liquid fraction (εXR) inside the nozzle as a two-dimensional projection, i.e. integrated in the X-ray beam direction.</li> <li>X-ray particle tracking (XPTV) has measured the local velocity uT inside the nozzle, along the motion path of each tracer particle described by the radial (r) and vertical position (z) in consecutive frames. The velocity uT was normalised by the superficial gas velocity jg(z) = Qg / (π * R(z)2), with Qg denoting the gas flow rate of compressed air applied for foam generation, and R(z) denoting the radius of the cross-sectional area depending on the vertical position z. To compare different nozzles, the vertical position z was normalised by the total length L = 25 mm / tan(θ) of the nozzle depending on its half angle θ = 5°, 10°, 20°.</li> <li>Optical PIV adapted to foam (FoamPIV) has measured the time-averaged velocity uW through the transparent wall of the nozzle, i.e. at the nozzle radius r = R(z) depending on the vertical position z. As described above, the velocity uW was normalised by the superficial gas velocity jg(z), and the vertical position z was normalised by the total length L of the nozzle.</li> <li>Electrode pairs (EP) have measured the cross-sectional average values of the liquid fraction (εEP) upstream and downstream the nozzle, simultaneously to the X-ray radiographic measurement of the liquid fraction distribution (εXR) inside the nozzle.</li> </ul> The experimental data in this repository is structured into different folders and files as follows. <ul> <li>FoamNozzle_Overview.CSV gives an overview of all measurements runs, nozzles, and techniques.</li> <li>Level 1 are folders classified by the measurement technique: 01_XR: X-ray radiography, 02_XPTV: X-ray particles tracking velocimetry, 03_FoamPIV: Optical PIV adapted to foam, 04_EP: Electrode pairs.</li> <li>Level 2 are folders classified by the different nozzles, distinguished by the nozzle half angle θ = 5°, 10°, 20°, and divided into bottom and top part in the case of θ = 5°, 10°.</li> <li>Level 3 are TIF and CSV files of measurement results. <ul> <li>01_XR: Each TIF image shows the time-averaged distribution of the liquid fraction inside the nozzle; the liquid fraction (0 < εXR < 1) is indicated by the value of each pixel.</li> <li>02_XPTV: Each CSV file consists of three columns, namely the radial position (r, in mm), the normalised vertical position (z / L), and the normalised velocity (uT / jg(z)).</li> <li>03_FoamPIV: Each CSV file consists of two columns, namely the normalised vertical position (z / L), and the normalised velocity (uW / jg(z)).</li> <li>04_EP: Each CSV file consists of three columns, namely the cross-sectional average of the liquid fraction (0 < εEP < 1) downstream as well as upstream the nozzle, and the time (in s).</li> </ul> </li> </ul> The authors gratefully acknowledge the financial support provided by the German Research Foundation (DFG, under grant number HE 7529/3-1, project numbers 431077191 and 551239760), by the German Federal Ministry of Education and Research (BMBF, under grant number 03HY123E), and by the Summer Student Program at the Helmholtz-Zentrum Dresden-Rossendorf.