Dynamics of Water Ice Formation during the Operation of Vessel Cryoconcentrators

M. A. Ugolnikova ◽  
V. V. Chernyavskaya
2018 ◽  
Vol 610 ◽  
pp. A9 ◽  
Miwa Goto ◽  
Jeffrey D. Bailey ◽  
Seyit Hocuk ◽  
Paola Caselli ◽  
Gisela B. Esplugues ◽  

Context. Spectroscopic studies of ices in nearby star-forming regions indicate that ice mantles form on dust grains in two distinct steps, starting with polar ice formation (H2O rich) and switching to apolar ice (CO rich). Aims. We test how well the picture applies to more diffuse and quiescent clouds where the formation of the first layers of ice mantles can be witnessed. Methods. Medium-resolution near-infrared spectra are obtained toward background field stars behind the Pipe Nebula. Results. The water ice absorption is positively detected at 3.0 μm in seven lines of sight out of 21 sources for which observed spectra are successfully reduced. The peak optical depth of the water ice is significantly lower than those in Taurus with the same AV. The source with the highest water-ice optical depth shows CO ice absorption at 4.7 μm as well. The fractional abundance of CO ice with respect to water ice is 16-6+7%, and about half as much as the values typically seen in low-mass star-forming regions. Conclusions. A small fractional abundance of CO ice is consistent with some of the existing simulations. Observations of CO2 ice in the early diffuse phase of a cloud play a decisive role in understanding the switching mechanism between polar and apolar ice formation.

2008 ◽  
Vol 20 (20) ◽  
pp. 205108 ◽  
J Seyed-Yazdi ◽  
H Farman ◽  
John C Dore ◽  
J Beau W Webber ◽  
G H Findenegg

2003 ◽  
Vol 81 (1-2) ◽  
pp. 343-350 ◽  
E M Chuvilin ◽  
T Ebinuma ◽  
Y Kamata ◽  
T Uchida ◽  
S Takeya ◽  

Experimental results on hydrate- and ice-formation conditions in the pores of sandy sediments that have undergone temperature cycles are presented. Thermodynamic parameters of gas hydrate and ice formation in porous space were determined for CH4 and CO2 saturated sandy sediments. The experiments indicate that temperature and freezing cycles affect the thermodynamics of hydrate and water–ice in gas-saturated sediments. Temperature cycles increased the hydrate accumulation in the pore space of sediments and reduce the freezing temperature of the remaining pore water. PACS Nos.: 91.60Hg, 92.40Sn

1995 ◽  
Vol 272 (2) ◽  
pp. 442-446 ◽  
W. W. Duley ◽  
D. A. Williams

ChemInform ◽  
2010 ◽  
Vol 29 (34) ◽  
pp. no-no
A. B. HORN ◽  
J. R. SODEAU ◽  
T. B. RODDIS ◽  

2020 ◽  
Vol 143 (1) ◽  
F. Rodrigues ◽  
M. Abdollahzadeh ◽  
J. C. Pascoa ◽  
P. J. Oliveira

Abstract A novel design of the dielectric barrier discharge (DBD) actuator/sensor is proposed for mapping the location of icing on a surface. The new design uses segmentation of the embedded electrode of the DBD actuator. Segmented DBD actuator/sensor devices were fabricated and experimentally tested in terms of mechanical, thermal and sensing abilities. The sensing capability of the new actuator was analyzed experimentally. Stationary and dynamic icing tests were conducted and the electrical characteristics of the DBD were measured. A parametric study on the effect of the electrode dimensions on the degree of sensitivity of the device was performed. Experimental results show that by using a segmented configuration it is possible to sense the onset of ice formation and also to detect its location. Furthermore, it is possible to detect the initiation of the melting process and measure the time for the water/ice to be completely expelled from the surface. It is also shown that the segmented actuator has better deicing performance in comparison to the conventional actuators. It is also shown that the thermal and active flow control abilities are not compromised by the segmented configuration and thus this device may perform deicing, ice formation and location detection and active flow control.

1984 ◽  
Vol 106 (3) ◽  
pp. 498-505 ◽  
N. Seki ◽  
S. Fukusako ◽  
G. W. Younan

Experiments have been performed to investigate the ice-formation phenomena and the heat transfer characteristics for water flow between two horizontal parallel plates. The experiments were carried out under the condition that the upper and lower plates were cooled at the same uniform temperature, which was less than the freezing and the temperature of the water. The temperature of the plates ranged from −7 to −14°C with inlet-water temperature varied from 2 to 5°C. The cooling-temperature ratio θc ranged from 1.4 to 7.0. By using three different values of height H, 16, 30, and 40 mm between the horizontal parallel plates, the Reynolds number ReH were varied from 3.8 × 103 to 3.2 × 104. As a result of the present investigation, two different types of ice-formation were observed. One was transition ice-formation type, and the other was smooth ice-formation type. It was found that the transition ice-formation type occurred for ReH/θc0.741 < 104, while the smooth ice-formation type occurred for ReH/θc0.741 > 104. The relation equations for the ice-transition position and the heat transfer coefficients along the water-ice interface were extensively determined.

1999 ◽  
Vol 380 ◽  
pp. 117-140 ◽  

This paper presents the results of a series of laboratory experiments aimed at understanding the processes associated with surface freezing of a two-layer fluid. The flow configuration consists of a layer of cold, salty water overlying a relatively deep bottom layer of warm, saltier water. This situation is common in high-latitude oceans during periods of rapid ice formation. The experiments were conducted in a tank with well-insulated side and bottom walls, placed in a walk-in freezer with air temperatures from −12 to −20°C. A system of thermocouples was used to measure the temperatures at fixed levels in water, ice and air. Microscale conductivity and temperature probes were used to obtain vertical profiles of temperature and salinity in the water. In general, when external uxes of heat and salt are absent, such a system enhances static stability, in the sense that the net density difference between the layers increases with time. When external uxes of heat (because of surface cooling) and salt (rejected during ice formation) are applied, however, this fluid system may become unstable and overturning of fluid layers is possible. In addition, heat transport from the warmer bottom layer to the colder upper layer may be important, possibly leading to a reduction in the rate of ice formation compared to that of a homogeneous fluid with temperature and salinity identical to the upper layer. Descriptions of such physical processes are given using laboratory experiments, and quantitative measurements of salient parameters are compared with the predictions of a theoretical model developed to explicate the flow evolution.

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