Page 120 - Design and Operation of Heat Exchangers and their Networks

108 Design and operation of heat exchangers and their networks

Example AB 1,6 2 2
A B
1 1
∗ ∗ 2
ε 1 ¼ 1 ν a, bÞ ν a, bÞ + abK bðÞ
ð
ð
(3.200)
¼ 1 0:7290 0:7290 + 0:5 1 0:6321Þ ¼ 0:3229
ð

Example AB 2,5 2 2 and AB 3,5 2 2
A B A B
1 1 1 1
∗
f
½
ð
ε 1 ¼ 1+ hb, a, Kbðފ ν a, bފgν a, bÞ
ð
¼ 1+ 0:1666 0:7263Þ 0:7290 ¼ 0:3210 (3.201)
ð

Example AB 2,6 2 2 and AB 3,6 2 2
A B A B

1 1 1 1
∗
ε 1 ¼ 1 ν a, bފν a, bÞ hb, a, Kbðފ
½
ð
ð
½
(3.202)
¼ 1 0:7263Þ 0:7290 0:1238Þ ¼ 0:3233
ð
ð

Example AB 4,5 2 2
A B
1 1
ð
ð
ε 1 ¼ ν a, bÞ 1 ν a, bފ + μ a, bÞ
ð
½
(3.203)
¼ 0:7263 1 0:7263Þ +0:1228 ¼ 0:3216
ð