김형대 교수

In recent quenching heat transfer studies of nanofluids, it was found that deposition of nanoparticles on a surface raises its Leidenfrost point (LFP) considerably [Kim et al., Int. J. Multiphase Flow 35, 427 (2009) and Kim et al., Int. J. Heat Mass Transfer 53, 1542 (2010)]. To probe the physical mechanism underlying this observation, the effects of surface properties on LFP of water droplets were studied, using custom-fabricated surfaces for which roughness height, wettability, and porosity we

CHF characteristics of nano- fluids were investigated with different volumetric concentrations of nanoparticles. Pool boiling experiments indicated that the application of nano-fluids, instead of pure water, as a cooling liquid significantly increased the CHF. SEM (scanning electron microscope) observations subsequent to the pool boiling experiments revealed that nanoparticles were coated on the heating surface during pool boiling of nano-fluids. In order to investigate the roles of nanoparticle

Nanofluids (suspensions of nanometer-sized particles in base fluids) have recently been shown to have nucleate boiling critical heat flux (CHF) far superior to that of the pure base fluid. Over the past decade, numerous experimental and analytical studies on the nucleate boiling CHF of nanofluids have been conducted. The purpose of this article is to provide an exhaustive review of these studies. The characteristics of CHF enhancement in nanofluids are systemically presented according to the eff

The pool boiling characteristics of water-based nanofluids with alumina and titania nanoparticles of 0.01 vol % were investigated on a thermally heated disk heater at saturated temperature and atmospheric pressure. The results confirmed the findings of previous studies that nanofluids can significantly enhance the critical heat flux (CHF), resulting in a large increase in the wall superheat. It was found that some nanoparticles deposit on the heater surface during nucleate boiling, and the surfa

On a visible-transparent boiling surface, the detailed geometry of a microlayer can be detected using a total reflection technique combined with laser interferometry. On an infrared-opaque boiling surface, the surface temperature and heat flux distribution can be obtained using a high-speed infrared thermometry technique. In the present study, an experimental technique to study heat transfer in the microlayer is described that permits the simultaneous use of the total reflection combined with la