CBE 30356 - Lecture Notes - February 28, 2023
Announcements
Class notes
Read through pages 181-197 of the notes and view the online narration below. Don't forget to complete the quiz in Canvas!
The main points of the lecture were
- Heat transfer correlations for pipe flow
- Analogies between energy and momentum transport in pipes
- Heat exchanger analysis for cocurrent and counter current double pipe heat exchangers
Goals:
After this class you should be able to:
- Know how to calculate the heat transfer coefficient for turbulent flow in a pipe.
- Know how to calculate the area required for a given amount of heat transfer.
Reading
- The class notes.
- BS&L, 13.1 to 4, 14.1 to 3, 15.4-1
Problem of the Day:
In class today we will discuss the dimensionless groups we've looked at this semester and examine how to analyze a double-pipe heat exchanger. Brief notes on this are provided here.
Demonstration:
In class today we will demonstrate the fascinating problem of a double-diffusive instability. This occurs in many systems, notably in the ocean when warm salty water overlays cooler fresh water such as would occur in cases where there is melting ice. As the warm fluid cools down it becomes denser, and goes from being stably stratified (less dense fluid on top) to unstably stratified. This causes the growth of plumes of water changing places, and is a major mechanism for nutrient transport in the oceans. An interesting description of the phenomenon is found in the article by Huppert and Turner given here.
David.T.Leighton.1@nd.edu