The current work aims to improve the thermal conductivity of distilled water by dispersing electrolytic grade iron powder. Thermal conductivity of fluids is an important parameter in deciding their usability in various commercial applications. Nanoparticles dispersed in fluids generally show interesting properties with respect to thermal conductivity. Iron particles were dispersed in distilled water in different volume fractions (1, 2 and 3 percent respectively) and the resultant fluids were analysed in terms of their thermal conductivity. To study the effect of particle size, the as received iron powder was also ball milled and the same set of studies were repeated with the milled powder. All the conductivity measurements were carried out at room temperature the data were compared with the conductivity value of the pure distilled water. The effect of solid powder additions on distilled water results the increase in thermal conductivity with increase in concentration of iron powder. Effect of milled powder was also compared with that of un-milled powde
