Enhancement of nanofluid stability and critical heat flux in pool boiling with nanocellulose

• Published in: Carbohydrate polymers Vol. 213; pp. 393 - 402
• Main Authors: Hwang, Won-Ki, Choy, Seunghwan, Song, Sub Lee, Lee, Jaeyoung, Hwang, Dong Soo, Lee, Kwon-Yeong
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2019
• Subjects: boiling; cellulose; Cellulose nanofiber; cellulose nanofibers; cooling; cost effectiveness; Critical heat flux (CHF); Heat transfer; industry; Nanofluid; nanofluids; nanoparticles; Pool boiling; thermal stability; Thermo-fluid engineering; Thermo-fluid engineering; Critical heat flux (CHF); Nanofluid; Heat transfer; Pool boiling; Cellulose nanofiber
• ISSN: 0144-8617; 1879-1344; 1879-1344
• DOI: 10.1016/j.carbpol.2019.03.023

Alternative nanofluid containing carboxylated nanocellulose exhibits enhanced critical heat flux (CHF) and stable dispersion during pool boiling. [Display omitted] •Nanofluid containing cellulose nanofibers (CNFs) enhanced critical heat flux (CHF).•Chemical inertness and self-repulsiveness of CNFs manifested stable pool boiling.•Nanofibrous structure was beneficial for CHF enhancement. 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.