Thermomechanical flow of He II through porous bodies

The thermomechanical flow of He II through a porous body has been studied by means of a variational principle. For a given porosity, the flow is a maximum for uniform pores. For actual pores the flow is always less, the reduction being primarily determined by the constriction at bottle-necks. It is shown that the thermomechanical mass flow of He II can be inferred from a measurement at room temperature of the electric current flow through the interstices of the porous body when they are filled with a conducting medium. (author)