Pantzali et al. investigatedthe effects of CuO/water nanofluid as coolants in a miniature PHE
experimentally and numerically. They found that less nanofluid
flow rates were required at a given heat load and thus the pressure
drop of nanofluid was lower than that of water. Pandey et al. [2]
experimentally observed higher HTCs of Al2O3/water nanofluids
than water in a corrugated PHE. The HTC increased with increasing
Reynolds number and Peclet number as well as with decreasing
nanoparticle volume concentrations. The pressure drop of nanofluids
increased with increasing nanofluid volume concentrations and
was higher than that of water.
Onthe basis of the open literatures, it is found that heat transfer is
usually enhanced by using nanofluids when laminar flow is encountered
in simple geometries (i.e., circular tubes). However, the heat
transfer performance of nanofluids under turbulent flow is inconsistent.
Thus the authors are motivated to investigate the effect of using
nanofluids in complex geometries. The heat transfer and pressure
drop characteristics of Al2O3/water and MWCNT/water nanofluids
in a chevron PHE were experimentally investigated in this paper to
explore the possibility and efficacy of using nanofluids in compact
heat transfer systems. The results of nanofluids were compared with
those of water. Experimentally measured thermo-physical properties
of nanofluids (i.e., viscosity and thermal conductivity) were used
in this work. Possible pressure drop and heat transfer correlations
were proposed for water and nanofluids flowing in PHEs.