A thick-walled, stainless steel (AISI 316) pipe of inside and outside diameters 25 mm and 40 mm is heated electrically to provide a uniform heat generation rate of 0.8 × 106 W/m3. The outer surface of the pipe is insulated, while water flows through the pipe at a rate of 0.1 kg/s. Evaluate the properties of the stainless steel (AISI 316) at 400 K. Assume the tube surface is smooth and use the Gnielinski correlation for the Nusselt number. (a) If the water inlet temperature is 20°C and the desired outlet temperature is 40°C, what is the required pipe length, in m?