掺气挑坎通气量试验研究(研究生论坛）

为了避免高速水流对过流面的空蚀影响，国内外高水头泄水建筑物多采用强迫掺气设施，同时必须保证掺气空腔内有足够的通气量。通过模型试验，从水力参数方面研究了掺气挑坎通气量的影响因素。试验结果表明，影响通气量的原因主要分为两方面：一方面为水体本身容纳气体能力，主要由水深决定；另一方面为水流从底空腔中吸纳空气的能力，主要由挑坎流速和底空腔长度决定。分析得出：水深较小时，水体本身所能容纳的通气量对掺气起主导作用；水深较大时，挑流水舌能从空腔中吸纳的通气量对掺气起主导作用。分析试验结果，综合考虑水体自身的容纳空气能力和底部临空面卷气能力两方面原因，提出了掺气挑坎通风量的经验计算公式，可作为泄水建筑物掺气挑坎理论计算参考公式。

Experimental Study on Ventilation Volume of the Flip Bucket

By model test, the ventilation volume was studied through hydraulic parameters. The results showed that the ventilation volume was influenced by two aspects: On the one hand it was the ability of water to accommodate air itself, which was decided by the water depth mainly. On the other hand it was the ability of water to absorb air from the bottom of the cavity, which was decided by velocity at the flip bucket and cavity length. The analysis showed that when the water depth was shallow, the ability of water to accommodate air itself played a leading role in the development of aeration. when the water depth was deep, the ability of water to absorb air from the bottom of the cavity played a leading role in the development of aeration. Based on the test result, an empirical formula of ventilation volume about flip bucket was proposed considering the two reasons above.