Repeat Prob. 8–91 for a circular horizontal duct of 15-cm diameter.

Data from problem 91

A concentric annulus tube has inner and outer diameters of 25 mm and 100 mm, respectively. Liquid water flows at a mass flow rate of 0.05 kg/s through the annulus with the inlet and outlet mean temperatures of 20°C and 80°C, respectively. The inner tube wall is maintained with a constant surface temperature of 120°C, while the outer tube surface is insulated. Determine the length of the concentric annulus tube. Assume flow is fully developed.

Transcribed Image Text:

Water T, - Insulation 0 ↓ ↑D₁