Sub-micron dispersions of sand in water prepared by stirred bead milling and ultrasonication: A potential coolant

Sub-micron dispersions of ‘sand in water’ have been prepared by stirred bead milling of the micron-sized sand particles, followed by probe ultrasonication. The dependence of dispersion viscosity and thermal conductivity on particle volume concentration has been studied. The influence of ultrasonication on the above transport properties has also been investigated. An estimated 4% and 10% increase in heat transfer coefficient may be obtained under turbulent and laminar flow conditions respectively by utilizing these dispersions as coolants. Further experimental studies in heat exchangers are required to ascertain the suitability of these dispersions for cooling applications.

► Sand–water dispersions prepared by stirred bead milling and ultrasonication. ► Transport properties investigated as a function of particles concentration and temperature. ► Correlations developed for prediction of relative viscosity and thermal conductivity ratio. ► Enhancements in heat transfer coefficient over water estimated