STRATIFIED FLOW FILM BOILING INSIDE HORIZONTAL TUBES

Stratified flow film boiling inside a horizontal tube was investigated . A one-dimensional flow model was used to solve for the local vapor f ilm thickness and vapor velocity in the vapor channel in the circumfer ential direction. Analytical solutions for the local vapor film thickn ess and heal transfer coefficient at the bottom of the tube were deriv ed. The solutions were compared with expressions obtained for other ex ternal geometries. A simple experiment was also performed to provide l ocal heat transfer data for direct comparison. It was found that the l ocal heat transfer coefficient normalized with respect to h(0) can be represented by a single curve for different liquid inventory and initi al wall temperatures. The curve was expressed in the form of a polynom ial and it provides a simple way of calculating the local heat transfe r coefficient in stratified flow film boiling in horizontal tubes.