Relative Stability Between Nucleate and Film Boiling on a Nonuniformly Heated Plate Surface

Abstract

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.

Boiling of methanol and HFE-7100 on heated surface covered with a layer of mesh

“…The socalled ``equilibrium heat ¯ux'', q C , characterizes the relative stability between nucleate and ®lm boiling. A higher q C designates a lesser chance for the occurrence of non-hydrodynamic burnout [19].…”

Relative stability of subcooled flow boiling on non-uniformly heated, inclined flat surface

“…Lin et al [31] discussed the eects of heater orien- tation at a saturated condition on the basis of the equal-area criterion. Based on the heat conduction equation and the no-¯ux boundary conditions, the equal-area criterion can be stated as follows [29]:…”

“…Lin and Lee [29] demonstrated the feasibility of applying the equal-area criterion to interpret the multimode boiling data (the Maddock's criterion). With each q N and q F set in Fig.…”