Weitere Untersuchungen an der konstruktiv verbesserten Kohlesteinisolierung Heft 1

Abstract

The kohlestein insulation has been modified to improve the thermal properties. Two of the five gaps between the pressure tube and the kohlestein were sealed by teflon. Thus a bypass-flow through the First test ring should be elirninated. The tests have been carried out in the high pressure wind tunnel up to a pressure of about 4o bars. Helium temperatures of about 400 °C were reached. When operating with air the temperatures were restricted to 300 °C because of the corrosion. The maximum velocity was about 2o m/s. The sealed test ring 2 exhibited Iower heat fluxes and a more uniform heat flux distribution. The heat fluxes were higher for the succeeding rings which were not sealed. The inspection of the -Lest tube revealed the cracking of four kohlestein rings. This damage is supposed to be due to thermal stresses.