• Bulletin of the Korean Chemical Society
• /
• v.5 no.2
• /
• pp.82-86
• /
• 1984

The anomalous behaviors of supercooled water are explained by using a two-solid-like structure model in which an equilibrium is assumed between open structures and closed structures. Besides these structures, small fraction of monomer exists in liquid water. The anomalies of liquid water are classified into two groups: structural and energetic. The structural anomalies appear in enlarged fashions in a supercooled state where the free volume is small.

• Journal of the Korean Chemical Society
• /
• v.15 no.4
• /
• pp.171-175
• /
• 1971

Significant structure theory has been applied to the viscosities of supercooled liquids with success. In the supercooled region, the effect of free volume decrease is so significant that the thermal effects on the solid-like volume must be considered properly. In addition, the two state theories proposed by Jhon and Eyring for water and Litovitz et al. for boron trioxide have been successfully applied to the structure change in the liquid state. Considered liquids are benzene, carbon tetrachloride, p-xylene, water and boron trioxide.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.12
• /
• pp.850-856
• /
• 2007

In a supercooled or capsule type ice storage system, aqueous solution (or water) may have trouble with non-uniform dissolution though the system contributes to the simplicity of system and ecological improvement. The non-uniform dissolution increases the instability of the system because it may cause an ice blockage in pipe or cooling part. In order to observe the supercooled state, a cooling experiment was performed with pressurization to an ethylene glycol(EG) 3 mass% solution in stationary state. Also, the effect of the pressurization from 101 to 505 kPa to the dissolution of supercooled aqueous solution was measured with the dissolution time of the supercooled aqueous solution at a fixed cooling rate of brine. At results, the dissolution of supercooled point decreased as the pressure of the aqueous solution in the vessel increased. Moreover, the dissolution point increased as the heat flux for cooling increased.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.2
• /
• pp.578-584
• /
• 2013

Ice slurry that is a mixture of fine ice crystals and liquid water is a widely used working fluid in the ice thermal energy storage system due to its flowability and large latent heat of fusion. Generally ice slurry is made from supercooled water. But the excessive supercooling causes the water to freeze even worse to block the pipe. Additionally large degree of supercooling of water degrades the efficiency of the ice thermal energy storage system. Therefore the effective method to control the phase change from supercooled water to ice slurry is needed. In this paper we experimentally studied a novel method to generate the ice slurry from the supercooled water using the ultrasonic vibration. It was found that the cavitation impact of supercooled water by ultrasonic vibration can help the generation of ice slurry.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.5 no.1
• /
• pp.1-9
• /
• 1993

Mass transfer coefficients were measured for water vapor absorption into a LiBr-Water solution of 60wt% flowing down an absorber of vertical tube type. The absorber is copper tube of 25mm inner diameter and 1000mm length. The film Reynolds number were varied in the range of 35~130. The solution is fed from the top of the pipe, and the conditions of solution are supercooled liquid and superheated liquid. As results, the flowrates of LiBr solution which takes peak value of average absorption mass flux exist. Mass transfer coefficients decrease with increasing the flowrate of LiBr solution, and the decrease rate in the case of supercooled liquid is large as compared with that in the case of superheated liquid. But the absorption rate of supercooled liquid is decidedly superior to that of superheated liquid.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.9 no.2
• /
• pp.104-111
• /
• 1997

The freezing phenomenon of saturated water with the supercooled region in a horizontal circular cylinder has been studied experimentally by using the holographic real time interferometry technique. From the experiments, it was found that there were three types of freezing patterns. The first is the annular ice layer growing from the cylinder surface at a high cooling rate; the next is the asymmetric ice layer at a moderate cooling rate; and the last is the instantaneous ice layer growth over the full region at lower cooling rate. As the water was coolde from room temperature to the subfreezing point passing through the density inversion point, the freezing pattern was largely affected by the inversion phenomenon, which had much effected the free convection and was susceptible to influences from the cooling rate. When the cooling rate is high, supercooling energy is released before the water is sufficientry mixed by free convection. On the other hand, when the cooling rate is low, there is much time for the water to be mixed by free convection. This seems to be the reason why the different ice layer growths occur.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.09a
• /
• pp.398-399
• /
• 2005

• Food Science of Animal Resources
• /
• v.42 no.3
• /
• pp.467-485
• /
• 2022

Supercooling storage refers to lowering the product temperature below its freezing point without phase transition and has the potential to extend shelf life. Nevertheless, supercooled objects are in a thermodynamically unstable state, and nucleation can occur spontaneously. To achieve supercooling storage, slow cooling and insulation are essential. Hence, a stepwise algorithm for the supercooling storage of pork loins was designed and validated in this study. Pork loins were stored at 3℃, -18℃, and -3℃ (freezing), and supercooled for 16 days. All samples remained in a supercooled state and were unfrozen at the end of storage. Supercooled pork loins were superior in terms of drip loss, cooking loss, and water-holding capacity compared to frozen samples. Additionally, supercooling treatment prevented discoloration, increase of volatile basic nitrogen, and microbial growth. Thus, supercooling of pork loin was achieved using a stepwise program and was effective to maintain meat quality.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.7
• /
• pp.862-872
• /
• 1997

Ice formation in a horizontal circular cylinder has been studied numerically. From the numerical analysis results, it was found that there were three types of freezing pattern and that freezing phenomenon was affected largely by density inversion and cooling rate. The type of freezing pattern largely depends on the secondary flow which is generated by density inversion. When supercooling energy is released before the development of the secondary flow, the annular ice layer grows. If the energy is released when the secondary flow is considerably developed and the supercooled region is removed to the upper half part of the cylinder, an asymmetric ice layer grows. And if the energy is released after perfect development of the secondary flow, instantaneous dendritic ice formation over the full region occurs. Furthermore, this secondary flow was found to have an effect on heat transfer characteristics. The heat transfer rate becomes small at the instant when the secondary flow is generated, but becomes large with the development of the flow. It's concluded that for the facilitation of heat transfer it is desirable to keep water in liquid phase until the secondary flow is perfectly developed. This study gave an instruction of performance improvement of capsule type ice storage tank.

• Nuclear Engineering and Technology
• /
• v.38 no.3
• /
• pp.201-210
• /
• 2006

This article presents a brief overview of an important area of neutron scattering: the general principles and techniques of elastic, quasielastic and inelastic scattering from a system composed predominately of incoherent scatterers. The methodology is then applied to the study of water, specifically when it is confined in nanometer-scale environments. The confined water exhibits uniquely anomalous properties in the supercooled state. It also nourishes biological functions, and supports essential chemical reactions in living systems. We focus on recent investigations of water encapsulated in nanoporous silica and carbon nanotubes, hydrated water in proteins and water or hydroxyl species incorporated in nanostructured minerals. Through these scientific examples, we demonstrate the advantages derived from the high sensitivity of incoherent neutron spectroscopy to hydrogen atom motions and hydrogen-bond dynamics, aided by rigorous data interpretation method using molecular dynamics simulations or theoretical modelling. This enables us to probe the inter-/intramolecular vibrations and relaxation/diffusion processes of water molecules in a complex environment.