Numerical Investigation on Heat Transfer and Performance Number of Nanofluid Flow inside a Double Pipe Heat Exchanger Filled with Porous Media

Two common methods to augment heat transfer are the application of nanofluids and porous inserts. In the present work, heat transfer inside a double tube heat exchanger filled with porous media is analyzed numerically using two phase mixture model for the nanofluid flow and the Darcy-Brinkman-Forchheimer model for the flow inside porous media. Basically, porous media improve heat transfer at the expense of increasing pressure drop. A new PN (Performance number) -defined as the ratio of heat transfer to pressure drop on the base state (without porous media and nanoparticles)- is introduced to better judge the first law’s performance of configurations. Results indicated that by keeping  and increasing Reynolds number from ۵۰۰ to ۲۰۰۰, an increase of ۵۶.۰۹% was observed in the performance number. Furthermore, maintaining Reynolds number at Re=۵۰۰ and changing  from ۰.۰۰۰۱ to ۰.۱, results in an increase of ۱۳۸%. For pressure drop, by keeping  and increasing Reynolds number from ۵۰۰ to ۲۰۰۰, it is ۴۰ times. Furthermore, maintaining Reynolds number at Re=۵۰۰ and changing  from ۰. ۱ to ۰.۰۰۰۱, the pressure drop is ۲۵۰ times. Besides, adding ۳% nano particles to the base fluid enhances the performance number by about ۵۰%  and increase pressure drop by about ۲۰%.

Keywords:

CFD , Heat Exchanger , Performance Number , Porous Media