Application of Shear-Thickening Nanofluids in Enhanced Geothermal Systems: A Comprehensive Review

Abstract

Shear-thickening fluids (STFs), especially nanofluids, are one of the key research areas in the world at the present time because of their ability to increase viscosity in response to specific shear conditions. This transition in viscosity is of great interest in various fields, including mechanical platforms and smart structures to advanced protective fabrics and armor. This increase in viscosity under applied shear conditions can be of great interest in the development of enhanced geothermal systems (EGSs). However, there is currently less research on the potential application of these shear-thickening nanofluids in EGS reservoirs. In this comprehensive review, the basic mechanisms of shear-thickening behavior in nanofluids are explained, while the effects of nanoparticle concentration, size, and temperature on this mechanism have been discussed in detail. This comprehensive review highlights how such factors can be optimized to adjust the rheological properties of nanofluids in order to improve their performance in fluid flow in highly fractured EGS reservoirs. An in-depth review of existing literature indicated that the combination of hydrolusters formation and the thermal properties of the shear-thickening nanofluids can be optimized to provide a potential solution to some of the EGS challenges such as thermal short-circuiting and low thermal energy extraction efficiency. Despite the huge potential of STF nanofluids in EGS development, extensive experimental and numerical investigations are needed to realize the effectiveness of these fluids further.