Water at a mean temperature of 310 K and atmospheric pressure flows through a rectangular flow passage that has a hydraulically smooth surface. The flow passage is made of a high conductivity metal...

Water at a mean temperature of 310 K and atmospheric pressure flows through a rectangular flow passage that has a hydraulically smooth surface. The flow passage is made of a high conductivity metal and is subject to resistive heating, so that an
thermal boundary condition can be assumed (see Section 1.4.5 for the definition of
 boundary condition). The linear power (heat input rate per unit length) follows the relation: