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Fluid Dynamic clarification of Bubble Generation Phenomena in Human Body under the Decompressed Environments

减压环境下人体气泡产生现象的流体动力学澄清

基本信息

批准号：
05650169
负责人：
TSUJINO Tomoji
金额：
$ 1.09万
依托单位：
Kumamoto 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：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05650169/
关键词：
Bubble Submarine sickness Blood Gas embolism Gas diffusion Cavitation Biomechanics Fluid dynamics 血液

项目摘要

Submarine sickness is taken ill with vesication in dived human body, however very little is known about the dynamic mechanism of the sideration yet. The purpose of this report is to study experimentally and theoretically the bubble generation in human body from a viewpoint of fluid dynamics. First, the apparatus about bubble formation in liquids with pressure variation was manufactured for trial, which used to model for the environmental conditions in deep sea. By making the experiment applied this apparatus, it is found that the bubble density in liquid becomes high with increasing the decompression in the pressure vessel, and that the tendency is noticeably with an increment of the maximum additional pressure. As carbon dioxide was dissolved in liquid, the bubble densities in the liquid are three-quintuple times as compared with air, and some relatively large spherical bubbles with about 2mm in diameter are observed. For dissolved air, the spherical bubbles whose radii are about 1mm appear in the decompressed liquid. Cavitation phenomena around a high-speed rotating disk were studied in water and human blood. In blood, cavitation occurs at lower Reynolds number than in water. The cavitation noise level in blood is higher than in water. Numerical calculations were conducted by combination of the equation of motion for a bubble and the diffusion equation of gas. As a result, the bubble growth rate increases with the elapsed time, and the maximum radius of the bubble is large with the depth in sea. Small bubbles are affected by gas diffusion, consequently the growth rates of bubbles become large.

潜艇病是一种潜水后人体发生水泡的疾病，但其动力学机制尚不清楚。本报告的目的是从流体动力学的观点对人体内气泡的产生进行实验和理论研究。首先，研制了用于模拟深海环境条件的变压液体气泡形成装置。应用该装置进行实验，发现液体中气泡密度随压力容器内减压的增加而增大，且随最大附加压力的增加趋势明显。当二氧化碳溶解在液体中时，液体中的气泡密度是空气的3 - 5倍，并且观察到一些直径约2 mm的相对较大的球形气泡。对于溶解空气，减压后的液体中出现半径约为1 mm的球形气泡。在水和人体血液中研究了高速旋转圆盘周围的空化现象。在血液中，空化发生在比水中低的雷诺数。血液中的空化噪声水平高于水中。结合气泡运动方程和气体扩散方程进行了数值计算。结果表明，气泡的生长速率随着时间的推移而增大，气泡的最大半径随着海深的增加而增大。小气泡受到气体扩散的影响，因此气泡的生长速率变大。