(Solved): Consider a concentric tube annulus for which the inner and outer diameters are 25 and 50mm. Water ...

Consider a concentric tube annulus for which the inner and outer diameters are 25 and $50\mathrm{mm}$. Water enters the annular region at $0.035\mathrm{kg}/\mathrm{s}$ and $25^{?}\mathrm{C}$. If the inner tube wall is heated electrical y at a rate (per unit length) of $q^{?}=4000\mathrm{W}/\mathrm{m}$, while the outer tube wall is insulated, how long must the tubes be for the water to achieve an outlet temperature of $85^{?}\mathrm{C}$ ? What is the inner tube surface temperature at the outlet, where fully developed conditions may be assumed? Determine the length of the tubes to achieve an outlet temperature of $85^{?}\mathrm{C}$. in $\mathrm{m}$. $L=$ $\mathrm{m}$ Determine the inner tube surface temperature at the outlet, in ${}^{?}\mathrm{C}$. $T_{4y}=$ $?\mathrm{C}$ Prysical Properties Mathematical Functions