Authors:
P Reinke, T Beckmann, C Ahlers, J Ahlrichs
Publisher:
MDPI
Abstract:
Digital photography of cavitation in narrow gap flows, e.g., lubrication films in journal
bearings or squeeze film dampers, demands a high time-resolution and a solution to approaching
the particular spatial restrictions. Typically, the lubrication film thickness is in the range of a few
microns and the characteristic time for vapor bubble generation and collapse is about one millisecond,
respectively. The authors have developed a Journal Bearing Model Experiment, which is designed
according to similarity laws providing fully similar flow conditions to real journal flows while
offering ideal access to the flow by means of optical measurement equipment. Compared with
other methods, e.g., pulsed laser, electrical discharge, tube arrest, applied to produce vapor bubbles,
the work on hand applies a dynamic variation of the minimum film thickness to produce suction
cavitation, which proves the applicability of this novel approach to study vapor cavitation in fluid
films similar to lubricant flows. The results are obtained by means of digital high-speed photography
of vapor bubbles from inception to implosion triggered by the dynamic variation of the minimum
film thickness of a narrow gap flow. Moreover, the results are set in relation to a general overview of
cavitation processes.
... high-speed camera (IXCameras i-Speed 720) is used to capture bubble
formation and transport inside the liquid film. The maximum data capacity of the
camera is 20 Gpx/s. Hence, the resolution and frame rate have to be balanced ...
