caa a22 4500 606197206 CHVBK 20210128100928.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s00348-015-1979-6 doi (NATIONALLICENCE)springer-10.1007/s00348-015-1979-6 Optical measurements of gas bubbles in oil behind a cavitating micro-orifice flow [Elektronische Daten] [Uwe Iben, Fabian Wolf, Hans-Arndt Freudigmann, Jochen Fröhlich, Winfried Heller] In hydraulic systems, it is common for air release to occur behind valves or throttles in the form of bubbles. These air bubbles can affect the behavior and the performance of these systems to a substantial extent. In the paper, gas release in a liquid flow behind an orifice is analyzed by optical methods for various operation points. The bubbles are observed with a digital camera, and a detection algorithm based on the Hough transformation is used to determine their number and size. The appearance of gas bubbles is very sensitive to the inlet and outlet pressure of the orifice. Gas bubbles are only observed if choking cavitation occurs. An empirical relationship between an adjusted cavitation number and the appearance of gas release is presented. It is assumed that the observed bubbles contain mostly air. With the applied pressure differences, up to 30% of the dissolved air was degassed in the form of bubbles. Springer-Verlag Berlin Heidelberg, 2015 Iben Uwe Robert Bosch GmbH, Robert-Bosch-Campus 1, 71272, Renningen, Germany aut Wolf Fabian Robert Bosch GmbH, Wernerstrasse 51, 70469, Stuttgart-Feuerbach, Germany aut Freudigmann Hans-Arndt Robert Bosch GmbH, Robert-Bosch-Campus 1, 71272, Renningen, Germany aut Fröhlich Jochen Institute of Fluid Mechanics, Technische Universität Dresden, 01062, Dresden, Germany aut Heller Winfried Faculty of Mechanical Engineering/Process Engineering, Hochschule für Technik und Wirtschaft Dresden, 01069, Dresden, Germany aut Experiments in Fluids Springer Berlin Heidelberg 56/6(2015-06-01), 1-10 0723-4864 56:6<1 2015 56 348 https://doi.org/10.1007/s00348-015-1979-6 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00348-015-1979-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Iben Uwe Robert Bosch GmbH, Robert-Bosch-Campus 1, 71272, Renningen, Germany aut NATIONALLICENCE 700 1- Wolf Fabian Robert Bosch GmbH, Wernerstrasse 51, 70469, Stuttgart-Feuerbach, Germany aut NATIONALLICENCE 700 1- Freudigmann Hans-Arndt Robert Bosch GmbH, Robert-Bosch-Campus 1, 71272, Renningen, Germany aut NATIONALLICENCE 700 1- Fröhlich Jochen Institute of Fluid Mechanics, Technische Universität Dresden, 01062, Dresden, Germany aut NATIONALLICENCE 700 1- Heller Winfried Faculty of Mechanical Engineering/Process Engineering, Hochschule für Technik und Wirtschaft Dresden, 01069, Dresden, Germany aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/6(2015-06-01), 1-10 0723-4864 56:6<1 2015 56 348