Zan Wu^a, Zhaozan Feng^b, Bengt Sundén^a,*, Lars Wadsö^c

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-10, 2014, DOI:10.5098/hmt.5.18

Abstract Thermal conductivity and rheology behavior of two aqueous nanofluids, i.e., alumina and multi-walled carbon nanotube (MWCNT) nanofluids, were experimentally investigated and compared with previous analytical models. Information about the possible agglomeration size and interfacial thermal resistance in the nanofluids were obtained and partially validated. By incorporating the effects of interfacial thermal resistance, a revised model was found to accurately reproduce the experimental data based on the agglomeration size extracted from the rheology analysis. In addition, the thermal conductivity change of the alumina/water nanofluid with elapsed time was investigated. Thermal conductivity measurements were also conducted for alumina/water and MWCNT/water nanofluid mixtures. More >

Yu Chen^a , Shen Du^a, Dong Li^a, Yang Gao^b, Ya-Ling He^a,*

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-13, 2020, DOI:10.5098/hmt.15.19

Abstract Non-uniform heating and vapor blockage deteriorate the effectiveness of transpiration cooling, and an optimization method by using porous media with a gradually-changed structure is proposed. The numerical tool based on a two-phase mixture model and local thermal non-equilibrium assumption considering variable properties of coolant is applied. Porous media with linearly-changed porosity or particle diameter is analyzed. The transient results presented that the structure of gradually-changed porosity (or particle diameter) with appropriate parameters can delay the heat transfer deterioration. And it is confirmed that the present theoretical model is an effective tool for optimization design of transpiration cooling system. More >