FUNDAMENTAL STUDIES ON ICE ABRASIVE JETS

冰磨料射流的基础研究

• 批准号: 06651092
• 负责人: KIYOHASHI Hiroshi
• 金额: $ 1.34万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06651092/
• 关键词: abrasive jet; water droplet; ice particle; LNG; liquified nitrogen; liquified hydrogen; utilization of cold heat; supercooling; アブレシブ; ウォータージェット; メタン; 低温

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

冰磨料射流有望成为下一阶段的先进磨料射流。然而.由于缺乏对超高冷却速度下水滴结冰机理的基本认识，射流的发展一直没有成功。利用液化天然气（LNG）返回气相后的冷量制取冰粒是本研究的目标之一。本研究的目的是通过数值模拟和实验技术，特别是参考传热工程澄清水滴的冰生长机制。(I)作为研究的第一步，使用数值模拟的结果讨论了水滴的凝固时间。研究了周围物质（11 K的CH_4和21 K的H_2）、物质与水滴之间的相对速度（0 ~ 200 m/s）和水滴粒径（0.001 ~ 2.0mm）（int ...更多信息 （即277.15K）对液滴温度变化的影响。结果表明：（1）冻结温度，即每种尺寸水滴的过冷温度临界极限，随水滴直径的增大和水滴相对速度的减小而增大。(2)水滴在低温气体中的临界冻结时间受水滴直径的影响大于水滴相对速度的影响，H_2的临界冻结时间小于CH_4的临界冻结时间。(3)液滴冻结的临界飞行距离随液滴直径的增大而增大，随液滴相对速度的减小而减小。在临界飞行距离较短的情况下，H_2比CH_4更有效。(II)用几乎相同的模型讨论了水滴在液化CH_4、N_2和H_2中的凝固时间。(1)结果表明：（1）水滴在液化气体中的凝固时间比在各种气体中的凝固时间短。(2)液滴相对速度的增加对冰粒的生长没有效果。实验正在研制一种用于观测冰生长的装置。少

项目成果

KIYOHASHI,H.KOBAYASHI,R.and HANDA,K.: "Fundamental Studies on Ice Abrasive Jet -Effects of Droplet Diameter and Atmospheric Temperature on the Temperature Change of Water Droplet in Still Atmosphere." Proc. of 9th Annual Conference of Water Jet Technology

KIYOHASHI,H.KOBAYASHI,R. 和 HANDA,K.：“冰磨料射流的基础研究 - 水滴直径和大气温度对静止大气中水滴温度变化的影响”。

KIYOHASHI,H.and HANDA,K: "Studies on Utilization of Cold Heat of LNG-Growth Time of Ice Particles from Water Droplets in the Gas Phase" Proc. of Abstructs of Annual Spring Conference of MMIJ. 129 (1995)

KIYOHASHI,H. 和 HANDA,K：“LNG 冷热利用研究——气相水滴中冰粒的生长时间”，Proc。

KIYOHASHI,H.KOBAYASHI,R.and HANDA,K.: "Numerical Simulations on Growth of Ice Particles for Ice Abrasive Jets." Proc. of 4th Pacific Rim International Conference on Water Jet Technology. 175-186 (1995)

KIYOHASHI,H.KOBAYASHI,R. 和 HANDA,K.：“冰磨料射流冰粒生长的数值模拟”。

幾世橋,広,小林,陵二,半田,啓二: "アイス・アブレシブジェットに関する基礎的研究-静止水滴の温度変化に及ぼす粒径と雰囲気温度の影響-" 日本ウオータージェット学会第9回研究発表講演会論文集. 43-52 (1994)

Ikusehashi、Hiroshi、Kobayashi、Ryoji、Handa、Keiji：“冰磨料射流的基础研究 - 粒径和环境温度对静止水滴温度变化的影响 -”日本水射流学会论文集第 9 次研究报告。 43-52 (1994)

KIYOHASHI,H.and HANDA,K: "Fundamental Studies on Ice Abrasive Jets-Growth of Ice Particles in LNG and Liquified Hydrogen" Proc. of 10th Annual Conference of Water Jet Technology Society of Japan. 1-10 (1995)

KIYOHASHI,H. 和 HANDA,K：“冰磨蚀射流的基础研究 - 液化天然气和液化氢中冰颗粒的生长”Proc。