Abstract:
The overall heat transfer of a cross flow heat exchanger can be enhanced by using the
nanofluids as coolant, which finds application in reducing the size and weight of automobile
radiator. However, improving the heat transfer using nanofluids can be accompanied by
simultaneous variations in the required pumping power. This study experimentally evaluates
the thermo-hydraulic performance of three nanofluids—metallic (copper, aluminum) and
nonmetallic (multiwalled carbon nanotube (MWCNT))—as coolant for an automobile radiator
by utilizing an in-house test rig. An enhancement in overall heat transfer coefficient can be
observed with nanocoolants (nanofluid as coolant), compared to the de-ionized water at
the same Reynolds number. The maximum enhancement in the overall heat transfer coefficient was observed to be 40, 29, and 25% for MWCNT, copper, and aluminum nanofluids,
respectively. The thermal performance of coolants was also compared with the same pumping power criterion. The overall heat transfer coefficient of nanofluids were higher than
basefluid at low pumping power range and the trend changes with increase in the pumping power. The present study shows that the heat transfer characteristics at the same
Reynolds number as well as at the same pumping power needs to be considered for the
selection of appropriate nanocoolant for automobile radiator application.
