有压输沙管道脉动压强特性试验研究

Experimental study on characteristics of fluctuating pressure in sediment flow pipeline

壁面脉动压强是工程上重要的研究对象,脉动强度直接影响泄洪排沙洞、输水隧洞(管道)等建筑物的稳定性和运行安全。为研究不同含沙浓度对壁面脉动压强特性的影响,以黄河细沙(d50=107μm)为研究对象,在直径80 mm的水平管道中进行模型试验,测量出每种工况下的流量、含沙浓度和脉动压强。采用统计方法对测量数据进行多方面分析,并结合快速傅里叶变换(FFT)方法研究了脉动压强的功率谱密度。试验结果表明,时均压强的沿程幅值和瞬时峰值压强均随含沙浓度增加而增大,相对脉动强度随着含沙浓度增大总趋势是减小的;脉动压强概率密度为脉动压强均值接近于零的正太分布,随着含沙浓度增加分布形态从瘦高型发展成矮胖型,压强振幅变大;脉动压强功率谱密度中低频分量随着含沙浓度变大有明显的增加。

The fluctuating pressure on the pipe wall is an important research object in engineering.The fluctuating intensity directly affects the stability and safety of buildings such as spillway tunnel and water delivery tunnel.In order to study the influence of sediment concentration on the characteristics of fluctuat⁃ing pressure in horizontal pipeline,taking the Yellow River fine sediment(d50=107μm)as the research ob⁃ject,a model test was carried out in the 80mm diameter horizontal pipeline,and the discharge,concentra⁃tion and fluctuating pressure of the pipe were measured.The statistical method is used to analyze the mea⁃surement data in many aspects,and the power spectral density of the fluctuating pressure is studied by combining the fast Fourier transform(FFT)method.The results show that the amplitude of time average pressure and instantaneous peak pressure increase with the increase of sediment concentration,and the val⁃ue of relative pressure intensity decreases with the increase of sediment concentration;the probability densi⁃ty of fluctuating pressure is close to normal distribution,and the distribution form changes from thin high type to short fat type with the increase of sediment concentration,and the amplitude of fluctuating pressure also increases;the low frequency energy of fluctuating pressure increases obviously with the increase of sed⁃iment concentration.