DA-2399 -- Freezing Process Between Two Concentric Pipes with a Constant Heating Temperature at the Inner Wall ✓ Most Recent

Consider any equipment utilizing a liquid with laminar flow through a duct across a regioncontaining a cold medium, which has a temperature lower than the solidification temperature ofthe fiuid. To prevent frost formation and reduction of flow viscosity, the fluid has to bewarmed. A method of warming the fluid is to use two concentric pipes with heat supplied at theinner wall and allowing the fluid to flow through the annular space. The heat supplied at thewall can be expressed by means of a constant wall temperature obtained, for example, by condensationof vapor at a fixed pressure. The heat removed at the outer wall is a result of heatconvection in a cold ambient medium. The freezing process may take place in the fluid when theheat removed at the outer wall is greater than that supplied at the inner wall. The rate ofpropagation of the phase boundary between the solid and liquid phases for such a case will bedetermined in this paper.