Question

1. Consider a 5 m long rectangular tube with a hot fluid with the properties specified in the diagram below. The inlet and outlet fluid temperatures are controlled to vary from 20 to 30 °C by applying a constant heat flux at the surface of the tube. We can ignore conduction and radiation phenomena in this problem and assume that the fluid velocity profile does not change within the tube. Using the Nu correlation from table 8.1 below, find the tube temperature at the outlet. Fluid Properties p 900 kg/m3 m2 v7-10-6 To 30 °C T ? Pr 10 C=2500 kg K W K =5 m K 0.3 m L 5 m 0.1 m u= 0.3m T 20 °C TABLE 8.1 Nusselt numbers and friction factors for fully developed laminar flow in tubes of differing cross section hD Nup k b (Uniform q Cross Section (Uniform T) a 4.36 3.66 1.0 3.61 2.98 1.43 3.73 3.08 b 2.0 4.12 3.39 a 3.0 3.96 4.79 4.0 5.33 4.44