operation. Assume that only the thermal resistance of the foulant would change
A shell-and-tube heat exchanger has tubes with 19 mm outside diameter and
the overall heat transfer coecient (the other conditions remaining unchanged).
1.2 mm tube wall thickn

resistance of the wall is neglected?
3.4
Explain the physical reasoning why " 1 eNTU for all ow arrangements when
C * 0.
3.5
(a) For a typical counterow heat exchanger, explain briey the change in the
eectiveness as the ow rate of the cold uid is decrease

ME421
Heat Exchanger and
Steam Generator Design
Lecture Notes 9
Compact Heat Exchangers
Introduction
Usually for gas-to-gas or liquid-to-gas flows
Surface area density roughly greater than 700 m2/m3 are
compact HEX
Surface area mostly increased by fins

ME421
Heat Exchanger and
Steam Generator Design
Lecture Notes 7 Part 2
Shell-and-Tube Heat Exchangers
Basic Design Procedure
Flow rates & compositions,
temperatures, pressures.
Process Eng Design Eng
Shell and head types, baffles,
tube passes, etc.
Prelim

ME421
Heat Exchanger and
Steam Generator Design
Lecture Notes 5
Fouling of Heat Exchangers
Fouling
Accumulation of undesirable deposit on a HEX surface.
Fouling occurs in natural systems as well.
Introduction
HEX are designed for thermal processes to wor

ME421 Fall 2012 HW4 Solution
(Shah and Sekulic Prob. 6.4):
PROBLEMS
423
6.4 The objective is to evaluate the pressure drop for air and water at (1) equal velocity
and (2) equal ow rate through a 25-mm-inside-diameter 3-m-long circular tube.

ME421 Fall 2012 HW1 Solutions
1. Equation 2.22 of Kakac & Liu can be written for PF HEX as
= ! ! = ! !
(1)
= (! ! )
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
Also for heat transfer between sides w

ME421
Heat Exchanger and
Steam Generator Design
Lecture Notes 8 Part 2
Gasketed-Plate Heat Exchangers
Heat Transfer & Pressure Drop Calculations
Design is specialized and proprietary.
Manufacturers have computerized design procedures for
their HEX.
Mos

ME421
Heat Exchanger and
Steam Generator Design
Lecture Notes 7 Part 1
Shell-and-Tube Heat Exchangers
Introduction
stationary-end head
shell
rear-end head
Introduction
Most widely used HEX, round tubes mounted in a shell
(cylindrical)
One fluid flows in

ME421
Heat Exchanger and
Steam Generator Design
Lecture Notes 4
Heat Exchanger Pressure Drop
and Pumping Power
Need for pressure drop calculations
Fluid friction effects cause pressure drop
Pressure drop calculation determines the pump power
requirement

ME 421 Steam Generator and
Heat Exchanger Design
Lecture 1
Introduction
Fall 2012
Assoc. Prof. Dr. lker Tar
itari@metu.edu.tr
210 2551
Course Objectives
After taking this course, you will
know common heat exchanger types, their advantages and
limitations;

ME421 HEAT EXCHANGER AND STEAM GENERATOR DESIGN
HOMEWORK 6 SOLUTION
FALL 2012
Start with the following design problem and Kern method solution. You are asked to complete detailed
shell side calculations (heat transfer and pressure drop) using Bell-Delawar