BOILING STABILITY CHARACTERISTICS OF METHANOL FLOWING OVER A NONUNIFORMLY HEATED SURFACE

The stability characteristics of methanol flow boiling over a nonunifo rmly heated surface has been investigated. An axial heat Aux distribut ion corresponding to a neutral stability condition, at which nucleate and film boiling can coexist steadily, was identified under various sy stem pressures, liquid subcooling and liquid flowrates. An increase (d ecrease) in the bottom heat flux under nucleate boiling mode would enh ance (weaken) the relative stability of the film boiling mode. Further more, nucleate boiling would become more stable under increasing liqui d subcooling. The dependence on system pressure is relatively weak. Th e 'equilibrium heat flux' is proven for the first time, to exist on an indirectly conductive heating surface, which can serve for direct com parison between stability characteristics among different boiling syst ems. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.