Under side radius =r1
Out side radius. =r2
Under side temperature =t2
Out side temperature =t1
Thickness =dr
Area=2πrl
Q=-KA (dt/dx)---(1)
Q=-K(2πrl)dt/dr
Q=-k2πrl(dt/dr)
dr/r=-k2πl/Q.dt---(2)
In equ 2 intigreting r and t
∫dr/r=-k2πl/Q ∫dt
lnr2 - lnr1=-k2πl/Q(t2 - t1)
ln[r2/r1] =-k2πl/Q(t1 - t2)
Q= k2πl(t2 - t2)/ln[r2/r1]
This is the final equation of cylinder up to three layer
