Quasi-Steady Analysis of Simultaneous HT and MT-3 — Lesson 4

This lesson covers the quasi-steady analysis of simultaneous heat and mass transfer, focusing on the evaporation of a water droplet suspended in a nitrogen atmosphere. The lesson explains the concept of transport phenomena and how it applies to non-Newtonian fluids. It discusses the time-dependent behavior of the system and the use of a quasi-steady analysis to understand the problem. The lesson also delves into the mathematical aspects of the problem, developing equations for flux, interfacial balance, and energy conservation. It further explains how to solve these equations to find the time required for the droplet to completely evaporate. The lesson concludes with the calculation of the total time for evaporation.

Video Highlights

02:28 - Explanation of the process of evaporation of the water droplet and the changes in size and state of the droplet over time.
05:40 -Explanation of the process of developing the flux equation and the use of a control volume for mass balance.
09:05 - Discussion on the concept of interfacial balance equations for both the components nitrogen and water.
41:58 - Explanation of the conservation of energy equation for the system and the concept of Lewis number.
46:52 - Conclusion of the lecture with the calculation of the total time required for the evaporation of the droplet.

Key Takeaways

• The quasi-steady analysis is used to understand the time-dependent behavior of a system where both heat and mass transfer occur.
• The evaporation of a water droplet in a nitrogen atmosphere can be analyzed using transport phenomena.
• The mathematical aspects of the problem involve developing equations for flux, interfacial balance, and energy conservation.
• The total time for evaporation can be calculated using the developed equations.