Handong Global University, 558, Handong-ro, Heunghae-eup, Buk-gu, Pohang, Gyeongbuk, 37554, Republic of Korea.
Division of Integrative Bioscience and Biotechnology, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea.
Carbohydr Polym. 2019 Jun 1;213:393-402. doi: 10.1016/j.carbpol.2019.03.023. Epub 2019 Mar 7.
A nanofluid, which is an aqueous fluid with nanoparticles, is an attractive medium for enhancing critical heat flux (CHF); however, its instability over a long period of time due to sedimentation and aggregation has impeded its successful application in industry. In this study, lightweight negatively charged TEMPO-oxidized cellulose nanofibers (CNFs) were utilized as a nano-sized substance in water and examined to enhance both the CHF performance and thermal stability of nanofluids. Owing to low density of the CNFs and long range repulsion between negatively charged CNFs, there were no aggregation and sedimentation of CNFs with multiple boiling/cooling cycles. In addition, with CNF concentrations of 0.01, 0.03, 0.05, and 0.10 wt%, CHF enhancement increases of 40.7%, 45.1%, 54.9%, and 69.4%, respectively, were achieved over that of pure water. The present results demonstrated the great potential of CNFs as eco-friendly and cost-effective nano-substances that can overcome the instability of nanofluids.
水基纳米流体是一种含有纳米颗粒的流体，是提高临界热流密度（CHF）的理想介质；然而，由于纳米颗粒的长期沉降和团聚，其在工业中的应用受到了阻碍。在这项研究中，利用轻质带负电的 TEMPO 氧化纤维素纳米纤维（CNF）作为纳米物质添加到水中，以提高纳米流体的 CHF 性能和热稳定性。由于 CNF 的低密度和带负电的 CNF 之间的长程排斥作用，CNF 在多次沸腾/冷却循环中没有聚集和沉降。此外，在 CNF 浓度为 0.01、0.03、0.05 和 0.10wt%时，相对于纯水，CHF 分别提高了 40.7%、45.1%、54.9%和 69.4%。本研究结果表明，CNF 作为一种环保且具有成本效益的纳米物质，具有克服纳米流体不稳定性的巨大潜力。
