Which pool boiling curve region corresponds to heat flux continuing to increase and reaching a maximum, known as Departure from Nucleate Boiling?

Which pool boiling curve region corresponds to heat flux continuing to increase and reaching a maximum, known as Departure from Nucleate Boiling?

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

Answer: (A)

As surface superheat increases in pool boiling, the nucleate boiling region has bubbles forming at the surface and departing into the liquid, which greatly enhances heat transfer and makes the heat flux rise. This rise continues until it reaches a maximum at the point of Departure from Nucleate Boiling, after which transition boiling begins. Beyond that, a vapor layer can form and heat transfer drops in film boiling.

As surface superheat increases in pool boiling, the nucleate boiling region has bubbles forming at the surface and departing into the liquid, which greatly enhances heat transfer and makes the heat flux rise. This rise continues until it reaches a maximum at the point of Departure from Nucleate Boiling, after which transition boiling begins. Beyond that, a vapor layer can form and heat transfer drops in film boiling.