INFLUENCE OF POROUS COATINGS ON HEAT-TRANSFER IN SUPERFLUID-HELIUM

Different types of porous materials as surface coatings on samples (Rh Fe wire) are investigated at HeIIs and HeIIp in respect to their influ ences on the heat transfer. Experimental results of measurements on sa mples with and without coatings are presented. Wires covered with capi llary filter plates as well as a mixture of gypsum and alumina abrasiv e show higher (up to 3.5 times) peak and recovery heat flux densities than those of the comparable bare wire at HeIIs. They show an increasi ng tendency of heat flux density with decreasing bath temperature at H eIIs similar to those at HeIIp. A discussion of the results is also gi ven in the paper.