Experimental study of influence of nanoparticles adhesion and sedimentation layer on solid-liquid interfacial thermal resistance

Solid-liquid (S-L) interfacial thermal resistance (ITR) is one of the key phenomena in the microscopic system where the interface plays a role in thermal transport, such as nanofluids. The changes in the S-L ITR in the case of the nanoparticle adhesion and sedimentation had not been experimentally characterized until now. In the present study, we experimentally investigated the changes in the S-L ITR when the ZrO₂ nanoparticle adhesion and sedimentation layer were formed on the stainless steel surface. We found that some portion of the nanoparticles inevitably adhered to the stainless steel surface. In the present study, the amount of the nanoparticle adhesion was not enough to change the macroscopic wettability and the S-L ITR. However, in the case of the nanoparticle sedimentation layer, the apparent S-L decreased, as the nanoparticle sedimentation became thicker. The tendency was consistent with the present thermal resistant model of the nanoparticle sedimentation layer. The nanoparticle sedimentation layer did not substantially influence the true S-L ITR. The above-mentioned findings are the basic knowledge that is beneficial and helpful for better understanding and designing the thermal conductivity measurements of the nanofluids, as well as the nanofluids heat transfer in flow channels.