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.