Assessment of thermal conductivity, viscosity and specific heat of nanofluids in single phase laminar internal forced convection

Nanofluids are considered for improving the heat exchange in forced convective flow. In literature, the benefit of nanofluids compared to the corresponding base fluid is represented by several figures-of-merit in which the heat transfer benefit and the cost of pumping the fluid are considered. These figures-of-merit do not account for the limited heat capacity of the fluid, the geometry and the flow conditions that in addition affect the temperature of the heat-transfer surface. We address these limitations by deriving a figure-of-merit that includes all the relevant thermophysical properties of the fluids, the flow conditions and the geometry of the heat-transfer device. This figure-of-merit is a useful benchmark tool to evaluate nanofluids in a laminar flow regime for heat sink applications.