Red 0.8 Pr0.4 after establishing that the flow is turbulent. For oil flowing through the annulus, find hydraulic diameter, Dh and Re. If Re is less than 2300, and the flow is laminar, you can use Nu =...

Red 0.8 Pr0.4 after establishing that the flow is turbulent. For oil flowing through the annulus, find hydraulic diameter, Dh and Re. If Re is less than 2300, and the flow is laminar, you can use Nu = 3.66, assuming uniform temperature along the annular surface. If the flow is turbulent, you have to use appropriate equation to find h₀. Find A₀
=
d₀L and then L.

Hints: By energy balance, Q = m_h
C_h
() We can fi nd the area by using Eq. (8.22), Q = U₀A₀F(T_lm) cf. Find (T_lm) cf, capacity

the shell side and subscript t refers to the tube side fluid. Consulting Fig. 8.20 and considering the mixed fluid as mixed and the oil as unmixed, we find the correction factor F and then A₀.