Page 121 - Design and Operation of Heat Exchangers and their Networks

Steady-state characteristics of heat exchangers 109

Example AB 4,6 2 2
A B
1 1
ð
ð
½
ε 1 ¼ 1 2ν a,2bÞ +2 ν a, bފν a, bÞ
ð
(3.204)
¼ 1 2 0:8006 + 2 0:7263Þ 0:7263 ¼ 0:3238
ð

Example AB 5,5 2 2
A B
1 1

ð
ð
ε 1 ¼ μ a, bÞ + μ b, aÞ=R 1
(3.205)
¼ 0:1228 + 0:3901=2 ¼ 0:3178

Example AB 5,6 2 2
A B
1 1

½
ð
ð
ð
ε 1 ¼ ν b, aÞ ν 2b, aÞ + μ b, aފ=R 1
(3.206)
¼ 0:4525 0:2026 + 0:3901Þ=2 ¼ 0:3200
ð
(Eq. (65) of Baclic (1990) is wrong. So Eq. (64) of Baclic (1990) is used
for the ε-NTU relationship, Eq. (3.206))

Example AB 6,6 2 2
A B
1 1

ð
ð
ð
ε 1 ¼ 1 ν 2a, bÞ 2ν a,2bÞ +2ν a, bÞ
(3.207)
¼ 1 0:5238 2 0:8006 + 2 0:7263 ¼ 0:3274