Heat Transfer Properties of Nanodiamond-Engine Oil Nanofluid in Laminar Flow

This study investigates the effects of utilizing nanodiamond as an additive to engine oil on the heat transfer enhancement in laminar pipe flow. A plain tube with internal diameter of 6 mm was used as the test section and heated by an electrical coil heater to produce a constant heat flux thermal boundary condition. Thermal conductivity, specific heat, and viscosity of nanofluids were measured for various volume fractions and temperatures. In addition, convection heat transfer coefficients and Nusselt numbers of nanofluids were obtained for different nanoparticle concentrations as well as various Peclet and Reynolds numbers. Experimental results clearly indicate the heat transfer enhancement due to the presence of nanoparticles in the fluid. However, pressure-drop measurements showed significant increase due to addition of nanopowder to engine oil.