SiO2 나노유체의 동적열전도율 향상에 대한 벽면에서의 나노입자 거동특성 영향

초록

The effect of nanoparticles migration near the wall on enhanced thermal conductivity in a flow of nanoparticle suspensions (nanofluids) under a constant wall temperature boundary condition was experimentally investigated in this study. The dynamic thermal conductivity of SiO2 nanofluids were measured by T-type thermocouples attached on the outer surface of a stainless steel circular tube (with 1m length and 1.75mm diameter). The nanofluids used in the experiments were synthesized by dispersing the SiO2 spherical nanoparticles of 24 nm in diameter in de-ionized water (DIW). The enhanced thermal conductivity of nanofluids (e.g., increase up to 7.9%) were demonstrated by comparing the temperature profiles in a flow of nanofluids with those of the based fluids (i.e., DIW). Furthermore, to explore the effects of morphology modifications by nanoparticle-wall interactions on heat exchanging surfaces (e.g., the precipitation of nanoparticles), the additional experiments were performed using DIW right after the measurements using nanofluids.