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UNIVERSITY OF JORDAN
CHEMICAL ENGINEERING DEPARTMENT
PROCESS HEAT TRANSFER (0905343)
Forced Convection (Tube bundle)
Instructor: Dr. Ali Al-Shawabkeh
In-class tutorial 4P
Problem 1:
A preheater involves the use of condensing steam at 100°C on the inside of a bank of tubes to heat
air that enters at 1 atm and 25°C. The air moves at 5 m/s in cross flow over the tubes. Each tube is 1
m long and has an outside diameter of 10 mm. The bank consists of 196 tubes in a square, aligned
array for which ST = SL = 15 mm.
Ts = 100°C
N = 196
S L = S T = 15 mm
Air
Ti = 25°C
To = ?
υ = 5 m/s
L =1m
D = 10 mm
a)- What is the total rate of heat transfer to the air?
b)- What is the pressure drop associated with the airflow?
Problem 2:
Air is flowing over a 5-row tube bank. The air enters the enclosing duct at a temperature of 288 K,
and it leaves at 312 K. The air flow is 0.236 m3/s, and is at atmospheric pressure. The staggered
tubes have an outside diameter of 0.025 m, and a length of 1.22 m. The outside surface temperature
Ts = 381 K
SL
S
= T = 2 .0
D
D
+
+
+
Air
0 . 236 m 3 /s
Ti = 288 K
+
+
+
+
+
+
+
+
L = 1 .22 m
+
+
+
+
+
+
+
+
+
To = 312 K
+
+
+
D = 2 .5 cm
+
+
of the tubes is maintained at a uniform temperature of 381 K. The longitudinal and transverse
S
S
pitches for the bundle are given by L = T = 2.0 . If the minimum free flow cross-sectional area
D
D
is 0.155 m2, calculate the average heat transfer coefficient.