Complex behaviour of a nanofluid near thermal convection onset: Its nature and features. (January 2017)

• Record Type: Journal Article
• Authors: Krauzina, Marina T.; Bozhko, Alexandra A.; Krauzin, Pavel V.; Suslov, Sergey A.
• Is Part Of: International journal of heat and mass transfer. Volume 104(2017:Jan.)
• Page Start: 688
• Page End: 692
• Publication Date: 2017-01
• Subjects: Heat transfer -- Oscillatory convection -- Hysteresis -- Nanofluid -- Transformer oil; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2016.08.106
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Conduction heat transfer in nanofluid is enhanced compared to pure transformer oil. Convection heat transfer in nanofluid is weaker than that in pure transformer oil. Hysteresis is detected in the conduction/convection transition in nanofluid. Convection in a nanofluid has an irregular oscillatory character. Abstract: The comparative experiments on conduction/convection in a ferro-nanofluid (Prandtl number 700) and its organic base, transformer oil (Prandtl number 300), are performed in a spherical cavity heated from above/below. The experiments show that the conductivity of a ferro-nanofluid increases compared to that of its base. However convection and the associated heat transfer are suppressed in a ferro-nanofluid relative to those in transformer oil. The investigation also reveals the existence of a hysteresis and oscillatory flow regimes near the convection onset in ferro-nanofluids and commercial transformer oil that fundamentally differ their behaviour from that of ordinary monofluids.