水射流扩孔喷嘴内部流场的数值模拟

Numerical simulation on internal flow field in a bore-enlarged nozzle with water jet

利用计算流体软件建立了土层扩孔喷嘴内部流场的三维数学模型.采用标准k-ε湍流模型模拟了喷嘴内部流场,并分析了喷嘴参数对流场速度分布、压力分布和出口速度的影响.结果表明,扩散角和扩散段长度对喷嘴内部流场影响较大,圆柱段长度的影响相对较小,但各参数都存在着最优值.计算结果与室内实验基本吻合,验证了喷嘴内流场分布与射流土层打击效果存在着内在联系.

A three-dimensional mathematical model of internal flow field in a soil bore-enlarged nozzle was established with the CFD software. Using the standard κ-ε turbulent model, the internal flow field in the nozzle was simulated and the influence of nozzle parameters on the velocity contour, pressure contour and outlet axial velocity of the flow field was studied. The results show that the diffuse angle and divergent cone length of the nozzle influence the internal flow field more and the effect of the cylindrical segment length is relatively less. The optimum values of all these parameters were proved to exist. Simulated results close to indoor test results, which accounts for the relationship between the internal flow field distribution in the nozzle and the soil impact effect of water jet.