Boiling Heat Transfer — Lesson 2

This lesson covers the topic of two-phase flow and heat transfer, focusing on boiling heat transfer. It delves into the differences between pool boiling and flow boiling, and explores different regimes of pool boiling heat transfer. The lesson also explains how the departure radius of a bubble varies with the degree of superheat and how heat flux can be evaluated when the bubble is growing. It further discusses the process of boiling, the differences between evaporation and boiling, and the methodologies for calculating flow boiling heat transfer. The lesson also provides an overview of the boiling curve and how it varies with the degree of superheat.

Video Highlights

01:23 - Process of boiling heat transfer
03:01 - Differences between evaporation and boiling
09:08 - Boiling curve and how heat flux varies with degree of superheat
23:00 - Rosenau correlation for nucleate boiling heat transfer
25:20 - Bromley's correlation for film boiling heat transfer

Key Takeaways

- Boiling heat transfer describes the process where the addition of heat causes a change of phase from liquid to gas.
- Boiling can be divided into two broad classifications: pool boiling and flow boiling.
- The departure radius of a bubble varies with the degree of superheat.
- The boiling curve shows how heat flux varies with the degree of superheat.
- The heat transfer coefficient in flow boiling is higher than in pool boiling.