Drift Flux Model — Lesson 4

This lesson covers the concept of two-phase flow and heat transfer, focusing on the drift flux model. It explains the applicability of the drift flux model in different adiabatic and phase change situations. The lesson also discusses the derivation of continuity and momentum equations applicable for the drift flux model and important terminologies involved. It further explores the different operating points for upward and downward movements of gas and liquid in a gas-liquid vertical pipe flow. The lesson concludes with the calculation of critical heat flux for departure from nucleate boiling.

Video Highlights

00:52 - Discussion on important terminologies involving the drift flux model.
05:25 - Derivation of equations related to the drift flux model.
08:18 - Explanation of the schematic of a situation where the drift flux model can be applicable.
14:23 - Derivation of the mixture continuity and momentum equations.
24:59 - Discussion on the operating points in a vertical pipe.
30:39 - Explanation of the concept of pool boiling crisis.

Key Takeaways

- The drift flux model is applicable in situations where there is a significant drop between the velocities of the gaseous phase and the liquid phase.
- The model considers the relative motion between the phases, leading to the derivation of continuity and momentum equations.
- The model is applicable for bubbly flow, slug flow, and droplet flow where the interface is not clearly distinct.
- The drift flux model helps in predicting the critical heat flux for departure from nucleate boiling.
- The model is useful in analyzing different operating points for gas-liquid two-phase flow.