Relative stability between nucleate and film boiling on a nonuniformly heated plate surface

Flow boiling of methanol over a nonuniform, indirect conduction heating surface is investigated experimentally. An axial (discrete) heat flux distribution corresponding to a neutral stability region where nucleate and film boiling can coexist steadily is identified. Below such a heat flux distribution, nucleate boiling mode is more stable. Above this distribution, film boiling mode becomes more stable. We had employed an equal-area criterion for interpreting the heat flux and wall superheat relationship. Analogy between the wire boiling system is proposed, The differences between average and real transition boiling curves are discussed as well.