不同流況下自動閘門水力特性試驗分析

自動閘門作用原理乃利用內外水位差使閘門進行自動啟閉，無需電動機械啟閉設備，使操作成本大幅降低。為了解不同流況下自動閘門之起閉情況，及其對閘門過流影響，本文遂利用水工試驗進行不同流量與不同水位影響下自動閘門啟閉情況之分析，針對自動閘門在不同流況及單位面積重之開度變化、流量係數與力矩平衡進行研究。結果顯示通過閘門之流況可概分為自由流與潛沒流兩類；自動閘門開度受到內水位、外水位及單位面積重影響，在相同流量及重量下，開度隨著潛沒程度升高而變大，並在反曲點後成反比，而在不同單位面積重之開度變化則明顯呈現反比現象；其開度變化亦可透過力矩平衡分析瞭解，水流作用於閘門之力矩主要為內水動壓所造成，而潛沒流時則會增加外水靜水壓之影響，透過動量方程式可概估作用於閘門上之動壓力，並利用力矩平衡公式分析閘門啟閉之機制；自動閘門之流量係數與潛沒程度關係呈現二次曲線，在不同流量時流量係數變化趨勢及區間皆相同。透過本研究對自動閘門的流量及其相關影響因子之分析瞭解，將有助於未來自動閘門設計分析之參考。

關鍵字

自動閘門；流量係數；水工試驗

並列摘要

The difference between inside and outside water level is the principle of automatically controlling the flap gate. This study used hydraulic experiment to analyze how the flap gate act under different flow situation, opening angle, discharge coefficient and moment balancing. According to the results, the flow situations were divided into free flow and submerged flow. The opening angle of the flap gate was effected by inside water level, outside water level, and per unit weight. In submerged case, the angle was proportioned to the degree of immersion, and turning into inverse after the inflection point. In addition, the opening angle was decreased with the area per unit weight increased. Moment equilibrium was used to analyze the flap gate mechanics. Torques induced by flows on the flap gate was introduced by inside water dynamic pressure in free flow situation, and the outside water dynamic pressure was appended in submerged flow situation. As a result, momentum equation could evaluate the dynamic pressure of the flow on flap gate. In addition, relationships between discharge coefficient and the degree of immersion of gate were the same at each discharge condition, and showed quadratic curve. Through the analysis of the discharge of flap gate and related factors, these results will benefit design and analysis of flap gate in the future.

並列關鍵字

Flap gate ； Discharge coefficient ； Hydraulic experiment

國際替代計量

不同流況下自動閘門水力特性試驗分析

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