Q$3.$ A double$-$pipe heat exchanger with inside tube dimensions $($I$.$ D$.2\mathrm{.}2$ cm and O$.$D$.2\mathrm{.}5$ cm $)$ is used as a condenser where steam condenses in an annulus at $54C$ outside the tube. The cooling water with $1k\frac{g}{s}$ flow rate enters at $20C$ and leaves at $36C.$ Determine the length of heat exchanger required. If the latent heat of condensation is $2454k\frac{J}{k}g,$ determine the condensation rate. Data available heat transfer coefficient for the steam is $7900\frac{W}{m^{2}C},$ water properties specific heat $-4180\frac{J}{kgC},$ viscosity $-0\mathrm{.}80{10}^{-3}k\frac{g}{m.s},$ thermal conductivity $($:$C\}$ for turbulent condition