In a pipe-within-a-pipe heat exchanger, water flows in the annulus and an aniline-alcohol solution having the properties listed in Problem 7.28 flows in the central pipe. The inner pipe has a 1.3-cm-ID and a 1.6-cm-OD, and the ID of the outer pipe is 1.9 cm. For a water bulk temperature of 27°C and an aniline bulk temperature of 60°C, determine the overall heat transfer coefficient based on the outer diameter of the central pipe and the frictional pressure drop per unit length for water and the aniline for the following volumetric flow rates: 

(a) Water rate 0.06 L/s, aniline rate 0.06 L/s; 

(b) Water rate 0.6 L/s, aniline rate 0.06 L/s; 

(c) Water rate 0.06 L/s, aniline rate 0.6 L/s; and 

(d) Water rate 0.6 L/s, aniline rate 0.6 L/s. (L/D = 400. ) Physical properties of aniline solution:

Data from in Problem 7.28

An aniline-alcohol solution is flowing at a velocity of 3 m/s through a long, 2.5-cm-ID thin-wall tube. Steam is condensing at atmospheric pressure on the outer surface of the tube, and the tube wall temperature 

Transcribed Image Text:

Temp- erature Viscosity (°C) (kg/m s) 20 60 100 0.0051 0.0014 0.0006 Thermal Conductivity (W/m K) 0.173 0.169 0.164 Specific Specific Heat Gravity (kJ/kg K) 1.03 2.09 0.98 2.22 2.34