Film Boiling Heat Transfer in Superfluid Helium

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1. Film Boiling Transfer in Superfluid Helium(He II)under Sathrated ConditionFilm boiling heat transfer from a horizontal Wire in super fluid helium under saturated condition was experimentally made clear for liquid temperatures ranging from 1.8 to 2.1 K. wire surface temperatures up to about 300 K and for the liquid heads above the wire ranging from 5 to 30 cm. Major conclusions are as follows :1)Film boiling heat transfer coefficients depend strongly on liquid head but weakly depend on liquid temperature within this experimental range.2. File Boiling Heat Transfer in He]I under Subcooled ConditionFilm boiling heat transfer from a horizontal in subcooled Hell at atmospheric pressure was made clear experimentally for liquid temperatures ranging from 1.85 to 2.15 K. Conclusions are as follows :1)Film boiling heat transfer coefficients under the subcooled conditions are higher than those for saturated conditions.2)Under subcooled conditions at atmospheric pressure, wire temperature for quasi-steadily increasing heat input does not jump at the critical heat flux but continuously increases to film boiling. Critical heat flux of Kapitza conductance regime and minimum heat flux of file boiling are almost same and no hysteresis effect is observed.3. Film Boiling ModelA new model for film boiling on a horizontal wire In Hell based on non-equilibrium kinetic effects at the vapoliquid interface and the HeII heat transport given expressed by the solution for Gorter-Mellink equatons was presented. It was confirmed that his model can describe our and other workers' experimental data of noiseless film boiling heat transfer coefficients on horizontal wires with the diameters ranging from 0.08 to 0.254 mm.