Experimental study of the combined effect of using nanofluid and microchannel techniques on nucleate and film boiling performance

In the present study, the nucleate and film boiling heat transfer of alumina-deionized water and silica-deionized water nanofluids in the presence of microchannel surface has been investigated experimentally. For this purpose, both types of nanofluids with volumetric concentrations of 0.1%, 0.3% and 0.5% were prepared using two-step method. Pure deionized water boiling experiments on polished and microchannel copper surfaces and nanofluid boiling experiments on microchannel copper surface were performed. The results showed that the combination of the presence of nanofluid and microchannel in the boiling process significantly increased the critical heat flux and the minimum heat flux. In the boiling of nanofluids on microchannel surface, the volumetric concentration of 0.5% had the best performance, so that the maximum values of critical heat flux and minimum heat flux for alumina-deionized water nanofluid increased by 93.02% and 105.32%, and for silica-deionized water nanofluid increased by 90.82% and 97.15%, respectively, compared to pure deionized water boiling on the polished surface. In addition, it was observed that with the deposition of nanoparticles on the microchannel surface, the surface wettability increased and the nucleate boiling heat transfer coefficient of nanofluids decreased compared to pure deionized water. But in film boiling, the effects of improving the thermal properties of nanofluids have overcome the destructive effects of nanoparticles deposition on the surface.