Showing papers by "Jung-Yeul Jung published in 2013"
TL;DR: The capability of recovery equipment to remove spill materials can be estimated, and the equipment should be prepared to mitigate the harmful effects of future oil and HNS accidents on humans and marine ecosystems.
50 citations
TL;DR: In this paper, the influence of nanoparticles on boiling heat transfer coefficient and CHF was investigated and it was found that the increase of CHF is proportional to the effective boiling surface area and the reduction of BHTC is mainly attributed to the blocking of the active nucleation cavity and the increased heat transfer resistance by nanoparticle deposition on the boiling surface.
Abstract: In this study, pool-boiling experiments are carried out to find out the influence of nanoparticles on boiling heat transfer coefficient and CHF. Each surface of the heater is visualized with FE-SEM and AFM after the experiments to figure out the effective boiling areas. The CHF increases up to 103% (compared to pure water) as the particle concentration increases until 0.001 vol% while it starts to decrease gradually as the particle concentration increases more than 0.001 vol%. It is found that the increase of CHF is proportional to the effective boiling surface area and the reduction of boiling heat transfer coefficient (BHTC) is mainly attributed to the blocking of the active nucleation cavity and the increase of the heat transfer resistance by nanoparticle deposition on the boiling surface. Finally, this study proposes a novel mechanism for BHTC reduction and CHF enhancement by nanofluids by considering the effective surface area variation.
29 citations
TL;DR: In this article, the effects of an ionic additive (i.e., nitric acid in this study) on the critical heat flux (CHF) behavior in pool boiling were investigated.
Abstract: TiO2/water nanofluids were prepared and tested to investigate the effects of an ionic additive (i.e., nitric acid in this study) on the critical heat flux (CHF) behavior in pool boiling. Experimental results showed that the ionic additive improved the dispersion stability but reduced the CHF increase in the nanofluid. The additive affected the self-assembled nanoparticle structures formed on the heater surfaces by creating a more uniform and smoother structure, thus diminishing the CHF enhancement in nanofluids.
28 citations
TL;DR: In this article, the authors investigated the CO 2 transport strategies from the sources to sinks for the CCS demonstration in Korea, and the cost estimations were carried out with the CO2 transport strategies.
28 citations
TL;DR: In this paper, the methanol (CH3OH)-based Al2O3 nanofluids are prepared for application of the CO2 removal system and the suspension stability and thermal characterizations are estimated by the Tyndall effect and by measuring the thermal conductivity of the nanoflids.
26 citations
TL;DR: In this article, the critical heat flux (CHF) and boiling heat transfer coefficient of H 2 O/LiBr-based binary nanofluids were measured using a plate copper heater.
Abstract: In this study, we measured the critical heat flux (CHF) and boiling heat transfer coefficient of H 2 O/LiBr-based binary nanofluids. By using the PVA (polyvinyl alcohol) as a stabilizer, Al 2 O 3 nanoparticles could be stably dispersed in H 2 O/LiBr. The plate copper heater (10 × 10 mm 2 ) is used as the boiling surface. The concentration of nanoparticle varies 0–0.1 vol%, dispersed in H 2 O/LiBr solutions (3, 7 and 10 wt% of LiBr). The results show that the boiling heat transfer coefficient of the binary nanofluids becomes lower than that of the base fluid as the concentration of nanoparticles increases while CHF of it becomes higher. We obtained an enhanced CHF of ∼48.5% (compared to the base fluid) with the 0.1 vol% Al 2 O 3 in 10 wt% LiBr aqueous solution.
26 citations
TL;DR: In this paper, the authors report the theoretical model to find the critical size of aggregates in nanofluids for the first time, which reflects the probability of encountering the particles.
Abstract: Stable suspension of the nanoparticles in the base fluids is inevitable to have the nanofluids be operated properly. Here we report the theoretical model to find the critical size of aggregates in nanofluids for the first time. The concept of relaxation time τ
r
is adopted, which reflects the probability of encountering the particles. The hydrodynamic diameter of the aggregates in nanofluids must be kept below the critical size to be stably suspended, which is in good agreement with the experimental results.
10 citations
TL;DR: In this article, the authors developed an economic evaluation model for CCS (Carbon Capture and Storage) chain where pipelines and ships were expected to come into play in transporting CO2 from power plants to offshore storage sites.
8 citations
TL;DR: In this paper, the authors investigated the transport properties and the gas cooling heat transfer coefficients of CO 2 -oil mixtures under gas cooling conditions for a CO 2 refrigeration system.
Abstract: The transport properties and the gas cooling heat transfer coefficients of CO 2 –oil mixtures were investigated under gas cooling conditions for a CO 2 refrigeration system. The viscosity and thermal conductivity of the CO 2 –oil mixture were predicted using the TRAPP model under the high pressure condition of around 10 MPa. Depending on the oil concentration, two different models: the homogenous model and separate model, were utilized to estimate the gas cooling heat transfer coefficient. Significant variations of the thermophysical properties of pure CO 2 with oil concentration heavily influenced the gas cooling characteristics of the CO 2 –oil mixture. The homogenous model for low oil concentrations (i.e. 1.0 wt.%) and the separate model for relatively high oil concentrations (i.e. 5.0 wt.%) predictions matched the previous experimental data with mean deviations of ±13.2% and ±33.4%, respectively.
7 citations
TL;DR: In this paper, the authors investigated the CO2 transport strategies from the sources to sinks (such as the saline aquifers and gas fields in the Southeast Sea of the Korean Peninsula) for the offshore carbon dioxide capture and storage (CCS) in Korea.
6 citations
TL;DR: In this article, the authors designed and built an experimental apparatus for simulating CO2-N2 mixture pipe-line transportation which consists of 4 parts with high pressure compression module, liquefaction module, mixing module, cooling module and transport test section.
TL;DR: In this paper, the authors studied the effect of porosity, permeability and wetting fluid saturation on the ascent of CO 2 in porous media and developed a new surface tension force model.
01 Sep 2013
TL;DR: In this paper, the effect of wind on the oil containment by boom was investigated using commercial computational fluid dynamics software, FLUENT with Volume of Fluid method, and the authors found that the effect becomes significant above the threshold velocity of 10 m/s.
Abstract: We numerically investigate the effect of wind on the oil containment by boom. The numerical simulations are carried out by using commercial computational fluid dynamics software, FLUENT with Volume of Fluid method. A boom containment of high viscosity oil in real scale is simulated, where the lengths of boom and simulated domain size are practical. It is found that the effect of wind becomes significant above the threshold velocity of 10 m/s. At wind velocity of 35 m/s, the leakage rate is twice larger than the leakage rate at 0 m/s.