Solution:
Water out
Water in
Given:
Outer diameter
Thickness
Then and
Let be the final temperature of the water and be the mass flow rate and let it be unity.
Assumption: and heat transfer takes place only through convection and conduction. Let the pipe made of copper so
From Incropera table A.6
Water properties
From Incropera table A.4
Air properties
Free convective heat transfer coefficient of air
As the ambient is infinite source of heat absorber it will remain same throughout the length of pipe.
Then heat lost by the water
Now using LMTD
Here overall heat transfer coefficient will be
Where water flow through the tube
So the flow is turbulent as
So the Nusselt number will be
So overall heat transfer coefficient will be
So
Solving equation (1) and (2)
Solving
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