Chapter 2 - Preparation and evaluation of stable nanofluids for heat transfer application

Abstract

Nanofluids are prepared by dispersing nanosize particles (less than 100nm) into base liquid. They are expected to be widely used in heat transfer due to their excellent thermophysical and rheological properties. Nanofluid stability, as the prerequisite in the study of nanofluids, is a critical bottleneck in the advances of nanofluids in heat transfer. Poor colloidal stability leads to particle aggregations and even precipitation, which result in corrosion of components, clogging of flow channels, and pressure drops. Therefore it is necessary to synthesize long-term stable and reusable nanofluids for successful industrial utilization. This chapter systematically reviews different aspects that can potentially improve nanofluid stability. Respectively, they are the preparation of nanofluids, evaluation of nanofluid stability, stabilization techniques, stability mechanisms, and effects of nanofluid stability on thermal properties. We hope this work can highlight nanofluid stability and the challenges related to industrial feasibility in heat transfer.