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Studies on elucidation of the air-water gas transfer mechanism on the surface of breakers and the modeling of it

破碎机表面空气-水气体传递机制的阐明及其建模研究

基本信息

批准号：
10450185
负责人：
KAKUNO Shohachi
金额：
$ 7.55万
依托单位：
Osaka City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10450185/
关键词：
bubble gas transfer breaker global warming PTV wind waves turbulence by oscillating grid microelectrode 再曝気

项目摘要

・By visualizing breaker image taken by a special video camera, the relation between bubble characteristics and wave characteristic in the breaker zone was analyzed.・The model formula of gas transfer velocity taking the effect of the entrained bubble in the breaker zone was proposed.・An image analysis technology with high-accuracy for measurement of the flow field in the breaker zone was developed.・Applying the laser induced fluorescence, the visualization of the entrainemnet process of CO_2 gas into the water-phase was succeeded.・It was found that the penetration depth of entrained bubbles of the plunging breakers is deeper than that of the spilling breakers.・It was found that the swell in the wind-waves promotes the gas transfer and that the effect of it becomes big as the wave period becomes shorter.・Gas transfer velocity at the water surface under the condition of the vibrating grating turbulent flow field was evaluated. The velocity was found to be controlled by the Large Eddy Model.・Distribution and change of CO_2 and N_2O on the subtropical equator of the Pacific Ocean were clarified.・The modeling of the gas exchange process for the bubbles entrained in the breaker zone was made, and the validity was verified from an experiment under the condition of a single bubble.・It was succeeded to visualize the entrainmenet process of bubbles into water by the breakers from the results of bubble observation in the field using ultrasonic wave and video image shot simultaneously.・State of the art on the studies of air-water gas transfer phenomenon was investigated through the literature.

通过专用摄像机拍摄破碎带图像，分析了破碎带内气泡特性与波浪特性的关系。提出了考虑夹带气泡影响的破碎区气体传质速度模型公式。开发了一种高精度的破碎带流场图像分析技术。应用激光诱导荧光技术，成功地实现了CO_2气体进入水相过程的可视化。结果表明，插入式破碎器的气泡穿透深度大于溢出式破碎器。结果表明，风浪中的涌浪对气体输送有促进作用，且涌浪的作用随风浪周期的缩短而增大。对振动栅湍流场条件下的水面气体传质速度进行了计算。发现速度受大涡模型控制。·阐明了太平洋副热带赤道上CO_2和N_2O的分布和变化。建立了气泡在破碎带内的气体交换过程模型，并通过单气泡条件下的实验验证了模型的有效性。利用超声波和同时拍摄的视频图像对现场气泡观测结果进行了可视化，成功地将破碎器破碎气泡入水的过程可视化。通过查阅文献，对气水传质现象的研究现状进行了综述。