Advanced Heat Transfer: Heat Exchangers
Log Mean Temperature Difference Method, Effectiveness NTU, Parallel Flow, Counter Flow, Shell and Tube, Cross Flow
What you’ll learn
- Recognize numerous types of heat exchangers, and classify them
- Develop an awareness of fouling on surfaces, and determine the overall heat transfer coefficient for a heat exchanger
- Perform a general energy analysis on heat exchangers
- Obtain a relation for the logarithmic mean temperature difference for use in the LMTD method
- Modify the LMTD method for different types of heat exchangers using the correction factor
- Develop relations for effectiveness, and analyze heat exchangers when outlet temperatures are not known using the effectiveness-NTU method
- Fundamentals of Heat Transfer Course
- Fundamentals of Fluid Mechanics Course
- Fundamentals of Engineering Thermodynamics
Heat exchangers are devices that facilitate the exchange of heat between two fluids that are at different temperatures while keeping them from mixing with each other. Heat exchangers are commonly used in practice in a wide range of applications, from heating and air-conditioning systems in a household, to chemical processing and power production in large plants. Heat exchangers differ from mixing chambers in that they do not allow the two fluids involved to mix.
Heat transfer in a heat exchanger usually involves convection in each fluid and conduction through the wall separating the two fluids. In the analysis of heat exchangers, it is convenient to work with an overall heat transfer coefficient U that accounts for the contribution of all these effects on heat transfer. The rate of heat transfer between the two fluids at a location in a heat exchanger depends on the magnitude of the temperature difference at that location, which varies along the heat exchanger.
Heat exchangers are manufactured in a variety of types, and thus we start this course with the classification of heat exchangers: Parallel Flow, Counter Flow, Cross Flow and Shell and Tube heat exchangers. We then discuss the determination of the overall heat transfer coefficient in heat exchangers, and the log mean temperature difference (LMTD) for some configurations. We then introduce the correction factor F to account for the deviation of the mean temperature difference from the LMTD in complex configurations. Next we discuss the effectiveness–NTU method, which enables us to analyze heat exchangers when the outlet temperatures of the fluids are not known.
Enjoy and happy learning!!
Who this course is for:
- Engineering Students
- Anyone Interested in Learning about Heat Exchangers
Author(s): Prof. Samer