Hot water at 80 degree C flows inside a copper pipe with a r

Hot water at 80 degree C flows inside a copper pipe with a radius of 4 cm (the thickness of the pipe wall is negligible) The pipe has a length of I m. Outside the pipe, there is an air flow at -10 degree C. To remove the heat, ten circular fins are installed on the pipe (sec the figure below for an example fin). These fins have a thickness of 0.1 cm (2t) and a radius (r_f) of 10 cm. Please draw the schematic of the resistance model with analog to the electrical circuit, and write out the resistance equation for each heat transfer. Please calculate the fin efficiency Please calculate the amount of heat removed for the pipe. The pipe and fins have a conductivity of 381 W/m^2K. The convective heat transfer coefficient is 250 W/m^2 K inside the pipe, and 15 W/m: K outside the pipe. You can assume that the bulk of the hot water has a constant temperature of 80 degree C in the whole pipe.

Solution

The answer of following question is as follows..

The fin efficiency is 76 % .

The heat removed from the pipe is 78 kw