scholarly journals Modeling of hot-point drilling in ice

2021 ◽  
pp. 1-14
Author(s):  
Yazhou Li ◽  
Pavel G. Talalay ◽  
Xiaopeng Fan ◽  
Bing Li ◽  
Jialin Hong
Keyword(s):  
Close Contact ◽  
Cone Angle ◽  
Ice Sheets ◽  
Water Film ◽  
Contact Melting ◽  
Head Shape ◽  
Ice Caps ◽  
Several Variables ◽  
Working Surface ◽  
Thin Water Film

Abstract Hot-point drills have been widely used for drilling boreholes in glaciers, ice caps and ice sheets. A hot-point drill melts ice through the thermal head at its bottom end. Penetration occurs through a close-contact melting (CCM) process, in which the ice is melted, and the meltwater is squeezed out by the exerted force applied on the thermal head. During the drilling, a thin water film is formed to separate the thermal head from the surrounding ice. For the hot-point drill, the rate of penetration (ROP) is influenced by several variables, such as thermal head shape, buoyancy corrected force (BCF), thermal head power (or temperature) and ice temperature. In this study, we developed a model to describe the CCM process, where a constant power or temperature on the working surface of a thermal head is assumed. The model was developed using COMSOL Multiphysics 5.3a software to evaluate the effects of different variables on the CCM process. It was discovered that the effect of thermal head shape and the cone angle of conical thermal head on ROP is less significant, whereas the increase in the BCF and the power (or temperature) of the thermal head can continuously enhance the ROP.

scholarly journals Marangoni spreading due to a localized alcohol supply on a thin water film

2015 ◽  
Vol 27 (3) ◽  
pp. 032003 ◽  
Author(s):  
José Federico Hernández-Sánchez ◽  
Antonin Eddi ◽  
J. H. Snoeijer
Keyword(s):  
Water Film ◽  
Thin Water Film

scholarly journals Equilibrium Profile of Ice Caps

1961 ◽  
Vol 3 (30) ◽  
pp. 953-964 ◽  
Author(s):  
J. Weertman
Keyword(s):  
Creep Rate ◽  
Ice Sheets ◽  
Additional Stress ◽  
Two Dimensional ◽  
Longitudinal Stress ◽  
Sliding Velocity ◽  
Ice Caps ◽  
Ice Cap ◽  
Rate Effects ◽  
Equilibrium Profile

AbstractNye’s theory of the equilibrium profile of two-dimensional ice caps is modified to include longitudinal stress and creep rate effects. A more generalized law for the sliding velocity of a glacier over its bed is introduced into the analysis in order to permit the inclusion of these additional complications. It is found that in the case of small ice caps (of the order of 30 km. in width), it is important to include the longitudinal stress. A somewhat “flatter” profile than that calculated by Nye is obtained. For ice sheets of the dimensions of the Greenland or Antarctic Ice Sheets, the additional stress causes essentially no modification in Nye’s theory. Nye’s theory also has been extended to include an isostatic sinking under the weight of the ice of the bedrock below an ice cap.

Simulation of New Wet Duster’s Nozzle Based on Fluent

2014 ◽  
Vol 556-562 ◽  
pp. 1133-1135
Author(s):  
Shan Shan Tang ◽  
Kai Song Wang ◽  
Chao Kun Wei ◽  
Teng Fei Ma
Keyword(s):  
3D Model ◽  
Water Pressure ◽  
Cone Angle ◽  
Wind Pressure ◽  
Safety Hazard ◽  
Field Simulation ◽  
Working Surface ◽  
Potential Safety ◽  
Normal Work ◽  
Nozzle Structure

Overweight of dust concentration is a common problem happened in most coal mine that not only affects workers’ normal work ,but also brings a great potential safety hazard to mine.New wet duster’ operating principle is that wind pressure and water pressure which generated in working surface pipeline network go through the nozzle jet and produce negative pressure leading the dust into dust catching pipe, and then the dust removed.According to optimizing the nozzle structure can increase spray’s cone Angle inside the shower nozzle,then the dust removal ability will be improved.The paper built the nozzle’ 3D model and the water’ the river basin model in SolidWorks ,then meshed them in Gambit and finally analysis the pressure and nozzle size’s influence on fluid’s pressure and velocity with Fluent’s flow field simulation.

scholarly journals Thin water film assisted glass ablation with a picosecond laser

Procedia CIRP ◽  
2018 ◽  
Vol 74 ◽  
pp. 328-332
Author(s):  
Edgaras Markauskas ◽  
Paulius Gečys
Keyword(s):  
Water Film ◽  
Picosecond Laser ◽  
Thin Water Film

Effects of convection and inertia on close contact melting

2003 ◽  
Vol 42 (12) ◽  
pp. 1073-1080 ◽  
Author(s):  
Dominic Groulx ◽  
Marcel Lacroix
Keyword(s):  
Close Contact ◽  
Contact Melting

scholarly journals Close contact melting of ice on circular cylinders

2018 ◽  
Vol 84 (858) ◽  
pp. 17-00339-17-00339
Author(s):  
Yasuaki SHIINA ◽  
Akira IFUKU ◽  
Satoru MORIYAMA
Keyword(s):  
Close Contact ◽  
Contact Melting ◽  
Circular Cylinders

Analysis of a Latent Heat Storage Device With Radial Fins

2013 ◽  
Author(s):  
Y. Kozak ◽  
T. Rozenfeld ◽  
G. Ziskind
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Latent Heat ◽  
Close Contact ◽  
Thermal Storage ◽  
Ambient Air ◽  
Contact Melting ◽  
Storage Device ◽  
Melting Time ◽  
Cfd Model

Phase-change materials (PCMs) can store large amounts of heat without significant change of their temperature during the phase-change process. This effect may be utilized in thermal energy storage, especially for solar-thermal power plants. In order to enhance the rate of heat transfer into PCMs, one of the most common methods is the use of fins which increase the heat transfer area that is in contact with the PCM. The present work deals with a latent heat thermal storage device that uses a finned tube with an array of radial fins. A heat transfer fluid (HTF) flows through the tube and heat is conducted from the tube to the radial fins that are in contact with the bulk of the PCM inside a cylindrical shell. The thermal storage charging/discharging process is driven by a hot/cold HTF inside the tube that causes the PCM to melt/solidify. The main objective of the present work is to demonstrate that close-contact melting (CCM) can affect the storage unit performance. Accordingly, two different types of experiments are conducted: with the shell exposed to ambient air and with the shell submerged into a heated water bath. The latter is done to separate the PCM from the shell by a thin molten layer, thus enabling the solid bulk to sink. The effect of the solid sinking and close-contact melting on the fins is explored. It is found that close-contact melting shortens the melting time drastically. Accordingly, two types of models are used to predict the melting rate: numerical CFD model and analytical/numerical close-contact melting model. The CFD model takes into account convection in the melt and the PCM property dependence on temperature and phase. The analytical/numerical CCM model is developed under several simplifying assumptions. Good agreement is found between the predictions and corresponding experimental results.

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