銳緣堰流量試驗

Abstract

中文摘要 水堰在水利工程中，可以量測明渠流控制斷面的流量，而於自來水公司的淨水廠以及汙水處理廠中也常用堰來估計水之處理量。銳緣堰流量試驗乃是人工渠道中水堰的縮小版，如果量得堰口上游的水位高度便可由理論知其流量。並可比較不同形狀的銳緣堰之理論流量與實測流量之差異，亦即流量係數之大致範圍。

本試驗以堰口流量試驗儀進行量測，水自出水口流出，經儀器底下流入，堰口上游部分以一平板分成二部分，堰口左方為靜水箱，平板右方為進水箱。水自出水口流入後，沿管往上流入進水箱。在平板中央處有一孔口，以一透明軟塑膠管與箱外透明量水桶底之孔口相連接，因連通管原理，靜水箱與量水桶保持在同一高度上。量水堰板以螺絲固定於支架板上，堰口下游為一底板略傾斜之集合水箱，自堰口溢流出水後，從箱底下之孔口，經一透明塑膠軟管，自量水孔口流回堰口流量試驗儀而構成一循環。

從試驗數據堰板正反方向流量之比較，得知本次實驗由於儀器較小所以數據沒有較大的差異顯示，若應用在大型儀器或是實際水庫測量則會有顯著差異。依試驗數據藉由回歸分析，求得各堰板實驗的流量係數值，藉以比較實際與理論流量係數之差異，推求梯形堰口的流量係數應位於矩形與三角形堰板的流量係數之間。

Abstract In the water conservancy project, water weir can measure control section flow of the open channel flow, water purification plant and sewage treatment plants used weir to estimate the amount of water treatment. The sharp crested weir flow test is a smaller version of the weir in the artificial channel, measuring the height of the weir upstream water will know the theoretical flow

Experimental equipment is weir flow tester, water flows from the water outlet and flows in from below the instrument, upstream to a plate divided into two parts. The left side of weir is stilling chamber, the right side of plate is water inlet chest. Due to the principle of connecting pipe, stilling chamber and gage tank kept at the same height. Weir plate screwed to the bracket plate, downstream weir is a slightly tilt collection tank, after the overflow water from the weir, the use of the bottom of the hole under the box, through a transparent plastic hose, water from the orifice back weir flow tester and constitute a cycle.

Comparison of the positive and negative flow of the weir from the experimental data shows that there is no significant difference in the data for this experiment due to the small size of the instrument, if used in large equipment or actual reservoir measurement will be significantly different. According to the experimental data by regression analysis, determine the flow coefficient of each weir plate experiment, in order to compare the difference between actual and theoretical discharge coefficient, trapezoid weir discharge coefficient should be located the rectangular and triangular weir discharge coefficient.