Theoretical and Experimental Investigation of the Melting Process of Ice Particles

2016 ◽  
Vol 30 (4) ◽  
pp. 946-954 ◽  
Author(s):  
Tobias Hauk ◽  
Elmar Bonaccurso ◽  
Philippe Villedieu ◽  
Pierre Trontin
2000 ◽  
Author(s):  
J. Jiang ◽  
Y. Hao ◽  
Y.-X. Tao

Abstract To improve the understanding of convective melting of packed solid particles in a fluid, an experimental investigation is conducted to study the melting characteristics of a packed bed by unmasking the buoyancy forces due to the density difference between the melt and solid particles. A close-loop apparatus, named the particle-melting-in-flow (PMF) module, is designed to allow a steady state liquid flow under a specified temperature. The module is on board NASA’s KC-135 reduced gravity aircraft for the experiments. In the test module, water is used as the fluid, and ice particles are fed to the test section at the beginning of the test. As the liquid flows though the bed, the solid grains melt. A perforate plate, through which liquid can flow while the ice particles are retained, bounds the downstream of the packed bed. From the digital video images the local packed bed thickness is measured under control flow rate, and the melting rate is determined. The temperature distribution along the horizontal direction and vertical direction is measured using 19 thermocouples. An infrared camera is mounted to record the local temperature variation between liquid and solid. The melting rates are presented as a function of upstream flow velocity, temperature and initial average particle size of the packed bed. It is found that the melting rate is influenced mainly by the ratio of the Reynolds number (Re, based on the initial particle diameter) to the square of the Froud number (Fr), and me Stefan number (Ste). In general, the dimensionless melting rate decreases as Re/Fr2 increases and increases as Ste increases. With the absence of gravity, i.e., Froud number approaches infinity, a maximum melting rate can be achieved for otherwise the same test conditions. The increase in the melting rate with the increase in Stephan number also becomes more pronounced under the zero gravity condition.


Author(s):  
Y. L. Hao ◽  
Y.-X. Tao

A series of experiments are conducted to investigate the characteristics and its effect on the melting and heat of a packed bed consisting of melting ice particles to horizontal forced convection. The volumes and situations of the melting ganular packed beds are by the visualization observations and measurements digital camcorders within the range of Re = 71 ~ 2291, Gr/Re2 = 1.48×10−5 ~ 17.32, and Ste = 0.0444 ~ 0.385, respectively. The mass of ice particles is measured at the time interval during the melting process. Two types of pattern can be found under the different conditions. The different types of heat transfer characteristics emerge in type of packing pattern. The correlations for each type of pattern are obtained based on the experimental results.


2005 ◽  
Vol 44 (2) ◽  
pp. 206-220 ◽  
Author(s):  
R. G. Oraltay ◽  
J. Hallett

Abstract Melting, freezing, and evaporation of individual and aggregates of snow crystals are simulated in the laboratory under controlled temperature, relative humidity, and air velocity. Crystals of selected habit are grown on a vertical filament and subsequently melted or evaporated in reverse flow, with the velocity adjusted for appropriate fall speed to reproduce conditions of the melting layer. Nonequilibrium conditions are simulated for larger melting ice particles surrounded by smaller drops at a temperature up to +5°C or growth of an ice crystal surrounded by freezing ice particles down to −5°C. Initial melting of well-defined faceted crystals, as individuals or in combination, occurs as a water layer >10 μm thick. For larger (>100 μm) crystals the water becomes sequestered by capillary forces as individual drops separated by water-free ice regions, often having quasiperiodic locations along needles, columns, or arms from evaporating dendrites. Drops are also located at intersections of aggregate crystals and dendrite branches, being responsible for the maximum of the radar scatter. The drops have a finite water–ice contact angle of 37°–80°, depending on ambient conditions. Capillary forces move water from high-curvature to low-curvature regions as melting continues. Toward the end of the melting process, the ice separating the drops becomes sufficiently thin to fracture under aerodynamic forces, and mixed-phase particles are shed. Otherwise ice-free drops are shed. The melting region and the mechanism for lowering the melting layer with an increasing precipitation rate are associated with smaller ice particle production capable of being lofted in weaker updrafts.


2010 ◽  
Vol 25 (2) ◽  
pp. 919-929 ◽  
Author(s):  
Xingliang Jiang ◽  
Songhai Fan ◽  
Zhijin Zhang ◽  
Caixin Sun ◽  
Lichun Shu

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