低弗氏掺气水流的阻力效应研究

Research of the Resistance Effect of Low Freund Aerated Flow

根据某水电站尾水洞模型试验观测到的水流现象与实测资料,分析了低弗氏水流在强迫掺气情况下,掺气浓度大小对水流沿程水面线、断面流速分布及沿程总水头线等水力要素的影响.分析表明:低弗氏水流掺气后存在减阻增速效应;水流掺气后其密度及黏性降低是产生减阻增速效应的主要原因,增加水流的掺气浓度,可相应提高减阻增速效应,减少能量损失.

According to the flow phenomena and measured data of the tailrace tunnel model test of a hydropower station, influences of the level of aeration concentration on hydraulic factors such as water surface profile along the way, velocity distribution, total head a- long the way and etc. were analyzed under the circumstance of the low Freund flow aerated by force. The results showed that the low Freund crated flow was of the effect of resistance decrease and velocity increasea, and which was caused by the reductions of density and viscosity of the flow after aerated. It also showed that increasing aeration concentration could accordingly promote the effect of re-sistance decrease and velocity increase as well as reduce energy loss.