Question

A counter current double pipe heat exchanger is used to boil but not superheat water at 100 DegreeC at rate of about 0.1 kg/s. This is achieved by flowing hot oil at 400 DegreeC through the inner pipe at a rate of 5 kg/s.

Latent heat of water: 2265 kJ/kg

Heat capacity of water: 4180 J/kgK

Heat capacity of the oil: 1800 J/kgK

What is the temperature of he hot oil leaving the heat exchanger?

What is the overall heat transfer coefficient if the diameter of the inner pipe is 40mm, and the tube length is 12m? Assume the pipe has negligible thickness.

Answer #1

A thin-walled double pipe counter flow heat exchanger is to be
used to cool oil (cp = 2200 j/kg*K) from 150 ℃ to 30 ℃ at a rate of
2.1 kg/s by water (cp= 4180 J/kg*K) that enters at 20 ℃ at a rate
of 1.2 kg/s. The diameter of the tube is 2.5 cm, and its length is
10 m.
Using Excel (a) Determine the overall heat transfer coefficient
of this heat exchanger. (b) Investigate the effects of oil...

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A concentric tube heat exchanger is comprised of a stainless
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3-nominal schedule 40 (ID = 77.9 mm, OD = 88.9 mm). The heat
exchanger has an effective length of 35 m.
The inner pipe fluid is ammonia (?a = 0.3 · 10?6
m2/s, cpa...

A concentric tube heat exchanger is comprised of a stainless
steel (ks = 40 W/mK) inner pipe, NPS 2- nominal schedule
40 size (corresponding to an inner diameter of 52.5 mm and an outer
diameter of 60.3 mm), and an outer stainless steel pipe of NPS
3-nominal schedule 40 (ID = 77.9 mm, OD = 88.9 mm). The heat
exchanger has an effective length of 35 m.
The inner pipe fluid is ammonia (va = 0.3 ·
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Cold water enters a counter flow heat exchanger at 20ºC at a
rate of 10 kg/s, where it is heated by a hot water stream that
enters the heat exchanger at 80ºC at a rate of 2 kg/s. Assuming the
specific heat of water to remain constant at Cp=4.18 kJ/(kg.ºC),
determine the maximum heat transfer rate and the outlet
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Saturated steam at 200 C, 1000 kg/h is used to boil toluene in a
heat exchanger. The toluene enters at 50 C, 1 bar, 3500 kg/h and
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Problem 8.24
Water is used to cool ethylene glycol in a 60-ft-long double
pipe heat exchanger made of 4-std and 2-std (both type M) copper
tubing. The water inlet temperature is 60°F and the ethylene glycol
inlet temperature is 180°F. The flow rate of the ethylene glycol is
20 lbm/s, while that for the water is 30 lbm/s. Calculate the
expected outlet temperature of the ethylene glycol and determine
the pressure drop expected for both streams. Assume counterflow,
and place...

Water is used to cool R-134a in the condenser of a heat
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500 kPa and 18 0C and leaves the condenser at 30 0C. Determine the
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Question 2. Answer all parts of this question a) A shell and
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heat transfer problem
A counterflow concentric tube heat exchanger is used to cool
lubricant oil of a big gas turbine. The cooling water's flow rate
through the interior aluminum tube (Di= 25mm) is 0.2kg/seg, while
the oil's flow rate through the exterior ring (Do= 45mm) is
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respectively. How long does the tube have to be for oil to leave at
60°C?
Oil at 80°C
Cp = 2131 J/Kg K...

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