Theory of Performance of Isothermal Solid-Nose Hotpoints Boring in Temperate Ice
Abstract The performance of a thermal ice-drill having a smooth, solid, impervious frontal surface, termed a “solid-nose hotpoint”, is determined by the velocities, pressures, and temperatures in the thin layer of warm melt water between the hotpoint and the ice. The efficiency, the speed of penetra...
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Cambridge University Press (CUP)
1962
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Online Access: | http://dx.doi.org/10.1017/s0022143000027362 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000027362 |
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crcambridgeupr:10.1017/s0022143000027362 2024-04-28T08:26:45+00:00 Theory of Performance of Isothermal Solid-Nose Hotpoints Boring in Temperate Ice Shreve, R. L. 1962 http://dx.doi.org/10.1017/s0022143000027362 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000027362 en eng Cambridge University Press (CUP) Journal of Glaciology volume 4, issue 32, page 151-160 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 1962 crcambridgeupr https://doi.org/10.1017/s0022143000027362 2024-04-09T06:56:15Z Abstract The performance of a thermal ice-drill having a smooth, solid, impervious frontal surface, termed a “solid-nose hotpoint”, is determined by the velocities, pressures, and temperatures in the thin layer of warm melt water between the hotpoint and the ice. The efficiency, the speed of penetration, the temperature of the frontal surface, and the distribution of pressure on it can be calculated from the equations of non-turbulent fluid flow. For hotpoints whose frontal surfaces are isothermal and axially symmetric, these quantities are functions of the total input of power Q of the weight W on the hotpoint, of the radius a and “shape factor” S of the frontal surface, and of the pertinent physical properties of water and ice. The calculation shows that with increasing “performance number” the efficiency E decreases and the surface temperature θ 0 increases. Thus, for example, E = 1·00 and θ 0 = 0°C. when N = 0.0 E = 0·76 and θ 0 = 48°C when N = 1.4; and E = 0·60 and θ 0 = 103°C. when N = 3.0. The coefficient Λ is a constant equal to . The shape factor S is a dimensionless number between 0 and 1 that varies according to the shape of the frontal surface, greater values of S being associated with blunter profiles (thus S = 1.0 for a plane frontal surface perpendicular to the axis). For coring hotpoints the same numerical results are obtained, but the performance number is given by where 2 ϖ i a is the inside diameter of the hotpoint. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Journal of Glaciology 4 32 151 160 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
spellingShingle |
Earth-Surface Processes Shreve, R. L. Theory of Performance of Isothermal Solid-Nose Hotpoints Boring in Temperate Ice |
topic_facet |
Earth-Surface Processes |
description |
Abstract The performance of a thermal ice-drill having a smooth, solid, impervious frontal surface, termed a “solid-nose hotpoint”, is determined by the velocities, pressures, and temperatures in the thin layer of warm melt water between the hotpoint and the ice. The efficiency, the speed of penetration, the temperature of the frontal surface, and the distribution of pressure on it can be calculated from the equations of non-turbulent fluid flow. For hotpoints whose frontal surfaces are isothermal and axially symmetric, these quantities are functions of the total input of power Q of the weight W on the hotpoint, of the radius a and “shape factor” S of the frontal surface, and of the pertinent physical properties of water and ice. The calculation shows that with increasing “performance number” the efficiency E decreases and the surface temperature θ 0 increases. Thus, for example, E = 1·00 and θ 0 = 0°C. when N = 0.0 E = 0·76 and θ 0 = 48°C when N = 1.4; and E = 0·60 and θ 0 = 103°C. when N = 3.0. The coefficient Λ is a constant equal to . The shape factor S is a dimensionless number between 0 and 1 that varies according to the shape of the frontal surface, greater values of S being associated with blunter profiles (thus S = 1.0 for a plane frontal surface perpendicular to the axis). For coring hotpoints the same numerical results are obtained, but the performance number is given by where 2 ϖ i a is the inside diameter of the hotpoint. |
format |
Article in Journal/Newspaper |
author |
Shreve, R. L. |
author_facet |
Shreve, R. L. |
author_sort |
Shreve, R. L. |
title |
Theory of Performance of Isothermal Solid-Nose Hotpoints Boring in Temperate Ice |
title_short |
Theory of Performance of Isothermal Solid-Nose Hotpoints Boring in Temperate Ice |
title_full |
Theory of Performance of Isothermal Solid-Nose Hotpoints Boring in Temperate Ice |
title_fullStr |
Theory of Performance of Isothermal Solid-Nose Hotpoints Boring in Temperate Ice |
title_full_unstemmed |
Theory of Performance of Isothermal Solid-Nose Hotpoints Boring in Temperate Ice |
title_sort |
theory of performance of isothermal solid-nose hotpoints boring in temperate ice |
publisher |
Cambridge University Press (CUP) |
publishDate |
1962 |
url |
http://dx.doi.org/10.1017/s0022143000027362 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000027362 |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 4, issue 32, page 151-160 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000027362 |
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Journal of Glaciology |
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4 |
container_issue |
32 |
container_start_page |
151 |
op_container_end_page |
160 |
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1797586003982024704 |