A pipe with flowing water is being heated in the radial direction at a constant flux of 1500 W/m. The flow rate of water is 12 liters per minute and the inlet temperature is 20C. The internal diameter of the pipe is 10 cm. The specific heat capacity can be treated as constant with a value of Cp = 4184 J/(kgC), as well as the density with a value of p = 1000 kg/m. If an outlet temperature of 90C is required, what is the necessary length of the pipe?