(Solved):   Consider the internal flow system shown in the figure. Assume the flow is fully developed ...

 

Consider the internal flow system shown in the figure. Assume the flow is fully developed both hydrodynamically and thermally. The properties of the fluid to be used are as follows: \[ k=0.670 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K} ; \quad \mu=352^{*} 10^{-6} \mathrm{~N} \cdot \mathrm{s} / \mathrm{m}^{2} ; \quad \rho=922 \mathrm{~kg} / \mathrm{m}^{3} ; \quad C_{\rho}=4181 \mathrm{~J} / \mathrm{kg} \cdot \mathrm{K} ; \quad \operatorname{Pr}=2.2 \] - What tube length \( L \) is required to obtain an exit temperature of \( 80^{\circ} \mathrm{C} \) ? - What is the surface temperature at the outlet of the tube?