Nonisothermal flow of helium II film

Abstract

The flow of helium II film is studied under conditions in which the temperature of the midpoint of the film can be changed in two ways. It is found that when cooling is effected by direct pumping on the film, flow is stopped with a cooling of about one millidegree. When cooling is by contact with a cold reservoir, however, there is no effect on the flow rate up to 40 millidegrees change. The film can thus flow through a temperature well. Further support is also given to the view that film transport rates are the same whether induced by gravitational or thermomechanical potential differences.