Zur vermeidung von thermischen effekten bei der messung der strömungsdoppelbrechung
article
In order to avoid the thermal perturbation of flow birefringence measurements a modified Couette-apparatus was developed. In the usual apparatus the heat of friction generated in the liquid is removed by thermal conduction through the cylinder walls. As discussed by Björnsthl8) a stationary distribution of temperature is established showing a maximum at the centre of the gap. Consequently the light used in the measurements is refracted and is partly reflected by the cylinder walls. This perturbation severely limits the measurement of small flow birefringences. It may be avoided by superimposing a slow motion of the liquid parallel to the axis on the main stream in the Couette-apparatus. This convection current removes an important part of the heat of friction. Its consequences were studied theoretically and experimentally. Essential for the method proposed here is the use of glass cylinders. Indeed, the high thermal conductivity of metal walls suppresses the effect of a slow convection stream. © 1956.
TNO Identifier
226660
ISSN
00318914
Source
Physica, 22(6-12), pp. 1197-1214.
Pages
1197-1214