What is the sequence of pool boiling curve regions from nucleate boiling to film boiling?

What is the sequence of pool boiling curve regions from nucleate boiling to film boiling?

• A. Nucleate Boiling → Transition Boiling → Film Boiling
• B. Nucleate Boiling → Film Boiling → Transition Boiling
• C. Transition Boiling → Nucleate Boiling → Film Boiling
• D. Film Boiling → Nucleate Boiling → Transition Boiling

Answer: (A)

The sequence reflects how boiling changes as the surface is heated more. In nucleate boiling, many small bubbles form at active sites on the heated surface and depart, effectively removing heat and giving high heat transfer. As heat input continues to rise, those bubbles grow and begin to coalesce, creating partial vapor coverage that insulates portions of the surface. This is the transition boiling region, where heat transfer becomes unstable and typically declines. With even higher heat flux, a continuous vapor film forms across the surface, fully separating the liquid from the heater; this is film boiling, with markedly reduced heat transfer. So the progression from nucleate boiling to transition boiling to film boiling follows the physical change from active bubble nucleation to partial vapor coverage to a complete vapor blanket.

The sequence reflects how boiling changes as the surface is heated more. In nucleate boiling, many small bubbles form at active sites on the heated surface and depart, effectively removing heat and giving high heat transfer. As heat input continues to rise, those bubbles grow and begin to coalesce, creating partial vapor coverage that insulates portions of the surface. This is the transition boiling region, where heat transfer becomes unstable and typically declines. With even higher heat flux, a continuous vapor film forms across the surface, fully separating the liquid from the heater; this is film boiling, with markedly reduced heat transfer. So the progression from nucleate boiling to transition boiling to film boiling follows the physical change from active bubble nucleation to partial vapor coverage to a complete vapor blanket.