机翼形量水槽过流流态探讨

Discussion on Flow Regime through Airfoil-shaped Measuring Flume

为深入理解流经机翼形量水槽等短喉道量水槽的水流流态提供理论依据,并以期指导该类量水槽的设计与灌区应用,以大量试验观测为基础,采用能量和临界流方程理论推导出在理想状态下临界流发生的位置;用断面比能法分析了喉道内水流能量与流态的转换关系,并对过槽水流从流态上进行定性的讨论和总结。结果表明:对于平坡渠道机翼形量水槽而言,临界流发生在渠道侧向收缩达到极小值的断面(即喉口断面);分析得到5种情况下的3类过槽流态(缓流,临界流,急流)符合试验观测。若能控制量水槽的过流流态为急流,则可以取得较好的测流效果。

The aim of this research is to provide theoretical supports for deeply understanding flow regime of flow through airfoilshaped measuring flume, which is classified into throatless type measuring flume, and to guide flume design and its application in irrigation districts. Based on experimental observations, energy and critical flow equations are introduced to deduce the location of critical flow in ideal condition, method of section specific energy is adopted to analyze relationship between energy and flow regimes. Flow regime of flow through flume is discussed and generalized qualitatively. The result shows that critical flow occurs in transverse cross section where lateral contraction gets minimal extremum （throat section） for airfoil-shaped measuring flume with horizontal bottom Through analysis, it is got that three kinds of flow regimes （sub-, super-, critical flow） under five different conditions are in accordance with experimental observations. More good water measuring performances will be obtained if flow can be controlled by supercritieal flow.