Mechanical Engineering Question:
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What is the formula for Heat loss in a pipe?
Answer:
Pipes are generally cylindrical in structure of amount of heat loss through pipe is given by the formula
Q= 2 pi k L (T1-T2)/ln (r2/r1)
Where
k=conductivity of material of which pipe is made
T1= temperature of inside layer pipe
T2=temperature outside layer of pipe
L= length of pipe
r1= inner radius
r2=outer radius
ln=natural logarithm
pi=22/7
The above condition applies for steady state flow, single layer over cylinder and neglecting conductivity
To take conductivity into account term Q* must be added
Q*=2 pi L {r1 hi (Ti-T1) +r2 ho (T2-To)}
hi=convective coefficient for inside layer
ho=convective coefficient for outside layer
Ti= temperature of inside space of pipe
To=temperature of outside space of pipe
Q= 2 pi k L (T1-T2)/ln (r2/r1)
Where
k=conductivity of material of which pipe is made
T1= temperature of inside layer pipe
T2=temperature outside layer of pipe
L= length of pipe
r1= inner radius
r2=outer radius
ln=natural logarithm
pi=22/7
The above condition applies for steady state flow, single layer over cylinder and neglecting conductivity
To take conductivity into account term Q* must be added
Q*=2 pi L {r1 hi (Ti-T1) +r2 ho (T2-To)}
hi=convective coefficient for inside layer
ho=convective coefficient for outside layer
Ti= temperature of inside space of pipe
To=temperature of outside space of pipe
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