Nanofluids: Introduction, Preparation, Stability Analysis and Stability Enhancement Techniques

Nanofluid was developed by suspending nanoparticles (such as metallic-Al, Cu & Ni or nonmetallic-metal oxides, grapheme etc.) in the range of 1-100 nm in the base fluid such as water, oil, and acetone. Nanofluids have wide scope in the field of heat transfer, nuclear science, solar energy and biomedical science. Nanofluids show unique and amazing properties because of high surface area to volume ratio (1000 times larger than of microparticles) of nanoparticles. The suspension of microparticles in fluid was initiated by Maxwell but it has many drawbacks like agglomeration and sedimentation. Two techniques of preparation of nanofluid have been discussed in this paper. Nanoparticles have slight tendency to agglomerate and sediment, so analysis of stability of nanofluid is a necessity. This paper describes various techniques for analysis of nanofluid stability along with techniques for enhancement of stability.