Improving Stability and Heat Transfer Performance of Nanofluids by Surface‐Modifying Nanoparticles With β‐Cyclodextrin

ABSTRACT Nanofluids have attracted considerable interest for enhancing heat transfer efficiency; however, poor stability remains a challenge. In this study, β‐cyclodextrin (β‐CD) was grafted onto TiO 2 nanoparticles using nitrogen filling and vacuum drying methods to improve the stability of nanofluids. The modified nanoparticles were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X‐ray diffraction. The stability and thermophysical properties of the nanofluids were evaluated in the temperature range of 20°C to 60°C. The results showed that the nitrogen filling method provided better grafting efficiency and stability, with a 36.62% reduction in settling velocity compared to the vacuum drying method. The β‐TiO 2 /EG:DI nanofluid exhibited a peak thermal conductivity of 0.579 W/(m·K) at 60°C, a 12.46% increase over the pure base fluid. Thermoeconomic analysis indicated that the β‐TiO 2 /EG:DI nanofluid has a maximum price‐performance factor of 1.206 under laminar flow at 50°C, representing a 23.67% increase compared to the unmodified TiO 2 /EG:DI nanofluid. These findings suggest that β‐TiO 2 /EG:DI nanofluid is suitable for industrial applications in the laminar flow regime.