We adopt the general theory of Non-equilibrium thermodynamics to
the two-fluid Model of He-II. In this Model superfluid is considered
as a fluid of two-components each of with its own density and velocity
fields. In contrast to the earlier works, our model assumes that super-fluid
carries small entropy ( ), owing to the Fliessbach. Since the fluid
has two independent velocity fields, there is no preferred frame of
references and hence, no unique definition of internal energy. The
explicit forms of this quantity are worked out in different models and
compared with our definition of internal energy and Gibbs function.
The existing relation and unification together with the equivalency of
London and Landau’s theories is also introduced
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