abstract
Thermal diffusivity is critical in optimizing processes across diverse industrial and scientific applications, including heat exchangers, electronics cooling, and energy storage systems. However, existing measurement techniques often rely on complex setups, advanced electronics, or parameter fitting, limiting their practicality for routine use. This study introduces a simplified temperature oscillation method for precise thermal diffusivity measurements that utilizes a cost-effective and reliable setup comprising a thermofoil heater and four thermocouples, requiring a small sample volume (similar to 1 ml). This makes it particularly well-suited for nanofluids, which are increasingly applied in advanced thermal management, innovative lubricants, pollutant remediation, and high-performance cooling systems. Experimental validation with water demonstrated excellent agreement with previously reported thermal diffusivity values, underscoring the accuracy and reliability of the technique. When applied to a luminescent nanofluid composed of NaGdF4:Yb/Er(18/2%)@NaGdF(4 )upconverting nanoparticles dispersed in water, the thermal diffusivity was comparable to that of distilled water challenging earlier reports of anomalous enhancements in nanofluid thermal properties.
keywords
CONDUCTIVITY ENHANCEMENT; THERMOCOUPLES; PROPAGATION; LIQUIDS; PHASE; WATER; HEAT; SIZE
subject category
Mechanics; Physics
authors
Raposo, RS; Brites, CDS; He, RH; Liu, XG; Carlos, LD
our authors
Projects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
This work was developed under the project CICECO-Aveiro Institute of Materials UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020, financed by national funds through the FCT/MECI (PIDDAC). R.S.R.F. acknowledges the financial support received from the Foundation for Science and Technology (FCT) through the research grant 2024/01558/BD.