中文摘要

　　電動液壓(Electro-Hydraulic)為目前成功大學發展之左心室輔助器(Left Ventricular Assist Device, LVAD)及全人工心臟(Total Artificial Heart, TAH)所採用的驅動方式。傳統舊式氣動(Pneumatic)系統龐大的驅動機構對病人術後生活造成相當大的負擔。此液壓系統將可有效縮小驅動裝置的體積，使病人獲得良好的行動能力與較佳的生活品質。為此，設計一個實用且具高效能的液壓泵便成為本裝置發展時相當重要的研究課題。本研究利用計算流體力學(Computational Fluid Dynamics, CFD)分析現有的混流式液壓泵(Mixed-flow Pump)，分別計算其在直管流道與上下游均具曲面的彎管流道中之性能表現，並將其結果與測試台實驗結果進行比對，以供日後進行液壓泵設計及修正流道幾何形狀的參考依據。研究結果顯示，此一液壓泵在直流管道中的性能表現符合原設計要求，數值計算結果與實驗結果亦相當吻合。但其在曲面彎管流道中的性能表現則不如預期。此一現象乃導因於流體在經過入流彎管後，立即進入液壓泵進行加壓，且在加壓後便經由下游彎管流出。彎管的影響使得此泵於操作點上壓升損失達68.7mmHg，而效能的損失達17%。這些現象亦於測試台上獲得證實。綜而言之，此一液壓泵的確可達設計所需效能，然欲將其運用在本研究之LVAD或TAH上，則須針對此一特殊流道重新設計液壓泵。

Abstract

　　Electro-Hydraulic power is the driving mechanism adopted on the NCKU Left Ventricular Assist Device (LVAD) and Total Artificial Heart (TAH). The huge size of conventional pneumatic driving system would cause great inconvenience to the patients in post-surgical daily life. The development of this hydraulic system can significantly reduce the volume of the driver, and the patients can acquire good activity and better quality of life as well. For this purpose, a practical and highly effective hydraulic pump design is one of the most important tasks while developing the NCKU LAVD and TAH. Commercial-used Computational Fluid Dynamics (CFD) softwares are utilized here to analyze the performance of current mixed-flow pump. Two flow field conditions, running channels with straight pipe and curved-surface pipe upstream/downstream respectively, are considered in this research. Simulating results are compared to the experimental ones, and provide reference material to further hydraulic system design and geometric modification of the channel shape. The results show that the performance of this hydraulic pump in straight running channel conforms to the designed requirements, and the computational results correspond to the experimental ones as well. However, the pump performance in the curved-surface running channel is contrary to expectation in that the flow gets into the hydraulic pump and is pressurized immediately after passing the upstream curved pipe, and then flows out by the downstream curved pipe after being pressurizing. At operation point, the influence of curved-surface running channel cost pump by 68.7mmHg pressure lose and 17% efficiency loss. In all, this hydraulic pump can really achieve the required effect. Nevertheless, being put in the LVAD or TAH, the hydraulic pump has to be re-designed on the special running channel.

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