河道底泥原位消减装置开发与试验

Development and test of in situ reduction device for river sediment

为应对因河道底泥过度淤积引起的河床升高、河流水位上升等问题,设计了一种河道底泥原位消减装置以实现底泥减量。研究利用计算流体力学技术(CFD)模拟在不同参数条件下装置内部压力分布及流速情况,确认可在旋流切割器内部产生充分涡流。对水力旋流切割器进行应力分析显示,旋流筒所受最大应力为0.203321 MPa,远小于钢材的屈服强度250 MPa,满足应力校核要求。同时,通过数值模拟对比10mm、15mm和20mm3种旋流桶出水口孔径的内外压差,证明使用15mm孔径可达到最好的臭氧微气泡产生效果。最终确定装置设计参数为旋流腔内径102mm,进水口内径28mm,出水口直径15mm。最后,检测发现装置运行30min内水体臭氧浓度提升至5.65 mg/L。2次试验,装置运行7 d后的底泥削减率分别达到39.94%和34.80%,证明装置具有良好的底泥原位消减效果。

In order to deal with river bed rise,river water level rise and other problems caused by excessive sediment deposition,a kind of in-situ sediment reduction device is designed to reduce the sediment.In this study,the computational fluid dynamics technology(CFD)was used to simulate the pressure distribution and flow velocity in the hydrocyclone under different parameters,and it was confirmed that sufficient eddy current could be generated in the hydrocyclone.The stress analysis of hydrocyclone cutter shows that the maximum stress of hydrocyclone cylinder is 0.203321 MPa,which is much less than the yield strength of steel of 250 MPa,and meets the stress checking requirements.At the same time,by comparing the pressure difference between inside and outside of the orifice of 10 mm,15 mm and 20 mm,it is proved that the best ozone microbubbles can be produced by using 15 mm orifice.Finally,it was found that the concentration of ozone in the water increased to 5.65 mg/L within 30 mins of operation.In two tests,the sediment reduction rates of the unit after 7 days operation reached 39.94%and 34.8%respectively,which proved that the unit had good sediment in-situ reduction effect.