射流式挖沟机沟内流场数值计算与分析

Numerical calculation and analysis of the flow field caused by a jetting trencher

针对某浅海射流式挖沟机沟内泥浆淤积问题,对其进行工作状态下的沟内流场数值计算和性能分析。通过合理简化物理模型和定义数值模型边界条件,结合多相流模型,利用成熟的商业数值计算软件实现流场计算过程。通过观察泥浆相的体积分数预估了沟内回淤情况,观察壁面剪应力和特征截面压应力评判了射流破土能力,得到合理的沟内流场性能。并根据不同的抽吸臂参数引起的沟内流场变化,选择出合适的抽吸臂布置方案。研究结果表明:提出的数值方法能用于快速计算挖沟机流场性能,合理估算泥浆相的输运状况,得到高效率的抽吸臂、喷冲臂布置组合。

The numerical calculation and performance analysis were carried out on the flow field caused by a jetting trencher in the normal working condition in consideration of the sedimentation in the trench. By reasonably simplifying physical model,defining boundary condition of the numerical model,and in combination with the multiphase flow method,the commercial numerical software was used to calculate the flow field. The sedimentation was predicted by observing the volume fraction of mud phase. The ability of breaking soil caused by jetting was evaluated by shear stress on the wall and stress on the specific plane,and then proper flow field performance were obtained.Comparing the diverse flow field performance in the trench caused by different parameters of suction arms,a suitable suction arms combination scheme was designed. The results showed that the numerical calculation scheme can rapidly simulate and analyze the flow field performance of this kind of jetting trenchers,and rationally evaluate the transportation of soil phase in the trench. The combination of suction arms and jetting arms with high efficiency can also be designed using this method.