Optical flow visualization system for the cryogenic environment

Abstract

Low temperature optical visualization provides an essential tool in understanding some types of fluid flow. We outline the various optical systems we have successfully used to visualize Rayleigh–Bénard convection in normal He4, with comparisons of image quality between each method. The current system uses a cooled charge coupled device camera at liquid nitrogen temperatures and a 1 mW laser diode light source for illumination.

Development of a camera casing suited for cryogenic and vacuum applications

“…However, the camera fully recovered after warming up the inner unit to 250 K. During earlier tests, the inner unit was cooled down to 77 K and the camera also fully recovered after warming up. Similar behaviour was reported by Seddon et al [4] who used a CCD camera to visualize cryogenic flow. At 250 K the camera works without any image degradation, and thus, this temperature was chosen as the nominal operation temperature.…”