1995 Fiscal Year Final Research Report Summary
FUNDAMENTAL STUDIES ON ICE ABRASIVE JETS
| Project/Area Number |
06651092
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
資源開発工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
KIYOHASHI Hiroshi TOHOKU UNIVERSITY,FACULTY OF ENG., ASSOC.PROF., 工学部, 助教授 (70005263)
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| Co-Investigator(Kenkyū-buntansha) |
ENOMOTO Heiji TOHOKU UNIVERSITY,FACULTY OF ENG., PROFESSOR, 工学部, 教授 (80005412)
KOBAYASHI Ryoji TOHOKU UNIVERSITY,FACULTY OF ENG., PROFESSOR, 工学部, 教授 (70006170)
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| Project Period (FY) |
1994 – 1995
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| Keywords | abrasive jet / water droplet / ice particle / LNG / liquified nitrogen / liquified hydrogen / utilization of cold heat / supercooling |
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| Research Abstract |
OBJECT OF STUDIES Ice abrasive jets are expected as a next stage advanced abrasive jet. However. the development of the jets have been not succeeded, because of lack of basic knowledge of ice growth mechanisms of water droplet cooled with super-higher cooling velocities. Utilization of cold heat from LNG (Liquified Natural Gas) at which is returned to gaseous phase for making ice particles is one of the target of this study. The objective of this study is to clarify the ice growth mechanisms of water droplets by numerical simulations and exper imental techniques with special reference to heat transfer engineering.
(I) Solidification times of the water droplet are discussed using results of numerical simulations as a first step of the research. The influences of the circumferential substance (CH_4 in 11OK and H_2 in 21K in cryogenic gaseous state), relative velocity (0 to 200m/s) between the substance and the water droplet, and particle diameter (0.001 to 2.0mm) of the water droplet (int
… More
ially in 277.15K) on thetemperature change of the droplet are using exact solution of unsteady heat conduction in sphere investigated theoretically. The following are summarized as the results ; (1) Freezing temperature, that is, critical limits of supercooling temperatures of each size of the water droplet is larger for larger droplet diameter and smaller relative velocities of the water droplet. (2) Critical freezing time of the water droplets in the cryogenic gases is more affected by the droplet diameter than the relative velocity of the droplet, and is shorter for H_2 than for CH_4. (3) Critical flight distance of the droplets to freeze them is longer for larger droplet diameter and is shorter for smaller relative velocity of the droplet. And H_2 is more effective for shorter critical flight distance than CH_4.
(II) Solidification times of the water droplet in liquified CH_4, N_2 and H_2 are discussed using almost the same model. (1) The following are summarized as the results ; (I) Solidification times of the water droplet in liquified gases are more shorter than that in each gas.(2) Increase of the relative velocity of the droplet is not effective for growth of the ice particles.
EXPERIMENT An observation apparatus for the ice growth is developing. Less
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Research Products
(10 results)
