• Journal of Institute of Convergence Technology
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• v.1 no.2
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• pp.29-32
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• 2011

In this paper, we will introduce the overview of new project dealing how to increase of refrigeration cycle COP using nano-fluids, CuO, TiO2, Al2O3, that are used on similar previous studies. Recently many studies were performed to show the effect of nano-fluids at refrigeration cycle. But, the reason was not cleared yet. In general, the flow phenomena at the evaporator were guessed to be mixed with the partial pool boiling condition and the flow boiling condition from the previous results not published yet. So, we hope that the COP increase of refrigeration cycle will be verified and showed through this project.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.1
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• pp.18-25
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• 1984

The transition boiling of a liquid droplet on a heated flat surface was studied utilizing Kotake's model with the effects of viscosity of a thin vapor layer between the droplet and the hot plate taken into account. This problem was analyzed considering the process of the droplet evaporation which resulted in hydrodynamic instability at the liquid-vapor interface. The results of the study are as follows; (1)The effect of the viscosity in the vapor layer at the interface appears as a dimensionless number N, namely .sigma. .delta.$_{0}$ /.rho.nu.$^{2}$ (2)The time required for evaporation at the transitional region increases with the temperature difference ratio .DELTA. T$_{r}$. The rate of increase of the total evaporation time becomes larger as increasing of N$_{m}$(N number at maximum heat flux) increases.s.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1317-1322
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• 2004

In this report, the heat transfer model of spray cooling on hot surface was developed by focusing on the effect of rebound motion of droplets. In the model, it was assumed that droplets rebound repeatedly on the hot surface and heat transfer upon droplet impact is proportional to sensible heat which heats up the droplets to the saturation temperature. In addition, to take account of the contribution of th heat flux upon impact of rebound droplets, it was assumed that the rebound droplets are distributed following the Gaussian distribution from 0 to L, which distance L is determined by maximum flight distance $L_{max}$. Also the calculated results were compared with existing experimental results.

• Journal of the Korean Applied Science and Technology
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• v.9 no.2
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• pp.181-187
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• 1992

This study was designed evaluate the change of fat content according to cooking methods of ground beef. The results are summarized as follows. 1. The fat content of ground beef is the lowest in boiling cooking method. 2. The fatty-acids composition of ground beef is mainly palmitic and oleic acids. The fatty acids hardly change according to cooking methods. 3. P/S ratio is inclined to increase a bit after cooking than pre-cooking. From all the results obtained in this study it can be conclude that fat content is the lowest in boiling and microwaving cooking methods and fatty acid composition is mainly palmitic and oleic acids.

• Korean Journal of Oriental Medicine
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• v.13 no.1 s.19
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• pp.63-68
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• 2007

Folk Remedies symbolize the medical art of the common people, and contain their special emotion and colloquial expressions. They are medical treatments in which the medical history and the tradition and the soul of a people are incorporated. They are handed down in various ways. This study introduces some of folk remedies. For example, powder of tigers' bones heals neuralgia. Rice wine brewing up with ginger is effective in a cold. Water boiling with safflower does good in neuralgia. Pasting herba houttuyniae takes effect in skin disease. To Decoct and drink old hardy orange is effective in urticaria. Water boiling with fructus corni alleviates a fever. Camellia oil or rhizoma cnidii or iris is used for the extermination of vermin and the antiseptic. In the end, the practical application of these remedies to the resources of industry and education will be discussed.

• Journal of Power System Engineering
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• v.14 no.4
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• pp.11-16
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• 2010

The evaporation heat transfer characteristics of propane(R-290) in horizontal small diameter tubes were investigated experimentally. The test tubes have inner diameters of 1 mm and 4 mm. Local heat transfer coefficients were measured at heat fluxes of 12, $24\;kW/m^2$, mass fluxes of 150, $300\;kg/m^2s$, and evaporation temperature of $15^{\circ}C$. The experimental results showed that the evaporation heat transfer coefficient of R-290 has an effect on heat flux, mass flux, tube diameter, and vapor quality. The evaporation heat transfer of R-290 has an influenced on nucleate boiling at low quality and convective boiling at high quality. The evaporation heat transfer coefficient of R-290 increases with decreasing inner tube diameter. And the evaporation heat transfer coefficient of R-290 is about 1~3 times higher than that of R-134a.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1283-1287
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• 2009

In this study, an analysis was performed on an evaporative steam generator (concentrator), where natural circulation convective boiling occurs on tube-side by condensing hot steam on shell-side. Existing correlations on two-phase pressure drop, boiling or condensation heat transfer were used for the analysis. The effect of number of tubes, tube length, etc. on thermal performance was investigated. Simulation results reveal that steam generation rate increases almost proportionally to the tube length, or number of tubes. It is also shown that water circulation rate decreases as tube length increases.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.337-342
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• 1996

The pool-boiling critical heat flux (CHF) of water on small flat plates has been experimentally investigated focusing on the effects of the inclination angle and size of the heated surface under near atmospheric pressure. The second-phase experiment was accomplished to find out the general CHF behavior for over-all inclination angles from -90$^{\circ}$ to 90$^{\circ}$using two plate-type test sections (30$\times$150 mm and 40$\times$150 mm) submerged in a slightly subcooled water pool. Test results generally confirm the first-phase findings and show little effect of inclination angle for inclined upward-facing cases. CHF position moves to lower position with the increase of the heater characteristic size and inclination angle(from -30$^{\circ}$to 60$^{\circ}$).

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.679-686
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• 1999

This study is to investigate the effect of a substantial drag reduction caused by the polymer(A611P) when the working fluids flow to the vertical direction in the vertical cylindrical equipment of closed flow system. The drag reduction is associated with the mechanical degrada-tion thermal degradation and heat transfer. By ignore the heat fluxs within the closed system the pressure drop due to the polymer concentration the flow velocity and flow time have been mea-sured. By taking into account the mechanical and thermal degradation in the closed system an experiment has been focused on the determination of the condition which could improve the pump capacity in the heat union electric power plant. Under the condition of non-boiling it has been found out that the change of heat flux has little influence on the drag reduction.

• International Journal of Advanced Culture Technology
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• v.3 no.2
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• pp.58-66
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• 2015

This paper aims to compare the use of Centrifugal Turbine and Tesla Turbine in an application of Organic Rankine Cycle (ORC) Machine using Isopentane as working fluid expanding. The working fluid has boiling point below boiling water and works in low-temperature sources between $80-120^{\circ}C$ which can be produced from waste heat, solar-thermal energy and geothermal energy etc. The experiment on ORC machine reveals that the suitability of high pressure pump for working fluid has result on the efficiency of work. In addition, Thermodynamics theory on P-h diagram also presented the effect of heat sources' temperature and flow rate on any work. Thus, the study and design on ORC machine has to concern mainly on pressure pump, flow rate and optimized temperature. Result experiment and calculate ORC Machine using centrifugal Turbine efficiency better than Tesla turbine 30% but Tesla Turbine is cheaper and easily structure. Further study on the machine can be developed throughout the county due to its low cost and efficiency.