Developent of Hypolimnitic Heavier Water Pumping System Using Air Bullets

将低磷水抽至自由水面，可起到水库富营养化保护、港口解冻、海产品促进等作用。在各种泵送系统中，利用空气弹通过保护罩将水推高，液压枪系统有望成为一种高效的系统。在这里，对系统进行了改进，使泵送的水在自由表面附近释放，以期望在下降阶段获得高携水率。在均质水和分层条件下，进行了一次气弹释放和周期性释放的实验，得到了整体和详细的流动结构。在此基础上，建立了均匀水和分层环境下系统的物理模型。然后，计算出抽气率和抽气速度随空气通量率和叶冠长度的函数关系、环境分层随时间的变化情况等。将实验结果与现场试验结果进行了比较。在对该系统进行分析的同时，还对气泡羽流等兼容系统进行了研究。首先，实验在线性分层和双层环境下进行。然后，得到了混合和泵速效率的几个重要特征。此外，还建立了环境密度分布变化的物理模型。利用这些结果，对气泡羽流系统和液压枪系统在各方面进行了比较。简而言之，液压炮系统在更小的深度和更重要的可靠性下变得更好。最后，作为该系统的应用，分析了泵送去富营养化的机理。然后，提出通过控制相对于光生层的温跃层深度，可以抑制光合浮游生物的产生。

Pumping the hypolimnion water to the free surface is available for the eutrophication protection of the reservoir, de-freezing the harbor, and promoting the marine products. Among various pumping systems, the usage of the air bullet to push up the water through a shroud, hydraulic gun systems is expected to be an efficient system. Here, the system was improved to release the pumped water near the free surface to expect the high entrainment rate at the falling stage.Various experiments, in a homogeneous water and in the stratification, one air-bullet release and the periodical release, were performed to get both bulk and detailed flow structures. Based on these, a physical model was developed for the system both in a homogeneous water and in stratified environments. Then, the following quantities were calculated : pumping rate and velocity as a function of the air flux rate and the length of the shroud, the ambient stratification change with time, etc.. These results were compared with both laboratory and field experiments.Together with the analysis just for this system, compatible systems such as bubble plumes were also studied. At first, experiments were performed both in linearly stratified and in two-layered environments. Then, several important features for the mixing and the pumping rate efficiencies were obtained. In addition, the physical model was developed to analyze the environmental density distribution change. Using these results, the comparison of the bubble plume system and the hydraulic gun system were made in various points. Briefly, the hydraulic gun system becomes better with smaller depth and in case that reliability is important.Finally, as an application of this system, de-eutrophication mechanism by pumping was analyzed. Then, it is proposed that by controlling the thermocline depth with respect to the euphotic layer, the production of photoplankton can be suppressed.