Heat Exchanger
MP3003/AE3003 Heat Transfer Semester 1, AY 2012-2013
(9) Heat Exchangers by Assoc Prof Leong Kai Choong School of Mechanical and Aerospace Engineering
Read Chapter 11 of the textbook before these lecture slides
© Dr. K.C. Leong, 2006 Lecture 2:Radiation & Conservation of Energy Requirement
Learning Objectives
At the end of these lectures, you should be able to: • recognise 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, and apply it for different types of heat exchangers using the correction factor, • analyse heat exchangers when outlet temperatures are not known using the effectiveness-NTU method, and • know the primary considerations in the selection of heat exchangers.
2
Introduction to Heat Exchangers
A heat exchanger is a device which facilitates the transfer of heat between two fluids - one hotter and the other colder.
Examples: Car radiator, refrigerator, air-conditioner.
Two methods for design and rating of heat exchangers: – Log Mean Temperature Difference (LMTD) – Effectiveness - Number of Transfer Units ( – NTU)
3
Scope
Heat exchanger types Overall heat transfer coefficient Heat exchanger analysis
Logarithmic mean temperature difference method Effectiveness-NTU method
Read Chapter 11 of prescribed text, Çengel, Y.A. and Ghajar, A.J., Heat and Mass Transfer: Fundamentals and Applications, 4th Edition (SI Units), McGraw-Hill, 2011.
4
Main Types of Heat Exchangers
Double-pipe heat exchanger
Cross-flow heat exchanger
Shell-and-tube heat exchanger
5
Double-Pipe Heat Exchanger
• Also known as Concentric Tube Heat Exchanger • Simplest design. One fluid passes through a pipe and the second fluid flows in the annulus
(9) Heat Exchangers by Assoc Prof Leong Kai Choong School of Mechanical and Aerospace Engineering
Read Chapter 11 of the textbook before these lecture slides
© Dr. K.C. Leong, 2006 Lecture 2:Radiation & Conservation of Energy Requirement
Learning Objectives
At the end of these lectures, you should be able to: • recognise 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, and apply it for different types of heat exchangers using the correction factor, • analyse heat exchangers when outlet temperatures are not known using the effectiveness-NTU method, and • know the primary considerations in the selection of heat exchangers.
2
Introduction to Heat Exchangers
A heat exchanger is a device which facilitates the transfer of heat between two fluids - one hotter and the other colder.
Examples: Car radiator, refrigerator, air-conditioner.
Two methods for design and rating of heat exchangers: – Log Mean Temperature Difference (LMTD) – Effectiveness - Number of Transfer Units ( – NTU)
3
Scope
Heat exchanger types Overall heat transfer coefficient Heat exchanger analysis
Logarithmic mean temperature difference method Effectiveness-NTU method
Read Chapter 11 of prescribed text, Çengel, Y.A. and Ghajar, A.J., Heat and Mass Transfer: Fundamentals and Applications, 4th Edition (SI Units), McGraw-Hill, 2011.
4
Main Types of Heat Exchangers
Double-pipe heat exchanger
Cross-flow heat exchanger
Shell-and-tube heat exchanger
5
Double-Pipe Heat Exchanger
• Also known as Concentric Tube Heat Exchanger • Simplest design. One fluid passes through a pipe and the second fluid flows in the annulus