The analog of the Reynolds criterion for boiling

A physical model describing the motion of vapor bubbles in a fluid boiling in a pipe or in a large container is constructed. The effect of the normal and tangential velocity components of vapor motion on hydrodynamic and heat exchange processes in bulk boiling is investigated. It is shown that the Reynolds criterion analog for bulk boiling should incorporate velocity of vapor motion, rather than the rate of vapor formation, as the characteristic velocity. A general equation describing heat exchange in bulk boiling in a pipe or large container is derived.