On the reliable estimation of heat transfer coefficients for nanofluids in a microchannel

7th European Thermal-Sciences Conference

Irwansyah, Ridho^1 ; Cierpka, Christian^1 ; Kahler, Christian J.^1

Institute of Fluid Mechanics and Aerodynamics, Bundeswehr University Munich, Neubiberg

85577, Germany^1

关键词: Constant wall temperature;    Convective heat transfer;    Diameter-size distribution;    Enhancement of heat transfer;    Heat transfer coefficient estimation;    Nanoparticle concentrations;    Nusselt number correlation;    Volume concentration;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/745/3/032078/pdf
DOI  :  10.1088/1742-6596/745/3/032078

来源: IOP

【 摘 要 】

Nanofluids (base fluid and nanoparticles) can enhance the heat transfer coefficient h in comparison to the base fluid. This open the door for the design of efficient cooling system for microelectronics component for instance. Since theoretical Nusselt number correlations for microchannels are not available, the direct method using an energy balance has to be applied to determine h. However, for low nanoparticle concentrations the absolute numbers are small and hard to measure. Therefore, the study examines the laminar convective heat transfer of Al2O3-water nanofluids in a square microchannel with a cross section of 0.5 x 0.5 mm2and a length of 30 mm under constant wall temperature. The Al2O3nanoparticles have a diameter size distribution of 30-60 nm. A sensitivity analysis with error propagation was done to reduce the error for a reliable heat transfer coefficient estimation. An enhancement of heat transfer coefficient with increasing nanoparticles volume concentration was confirmed. A maximum enhancement of 6.9% and 21% were realized for 0.6% Al2O3-water and 1% Al2O3-water nanofluids.