全射流喷灌喷头射流元件的流场分析

全射流喷灌喷头射流元件对喷头工作性能有重要影响，其内部液气两相流动影响着射流元件的尺寸设计。采用流体体积函数两相流数学模型，对射流元件稳定附壁情况下二维及三维流场进行数值模拟，获得射流元件壁面压力分布规律、射流中线速度衰减规律、无因次附壁点距离和液气两相界面坐标位置。壁面静压试验数据与计算值对比具有一致性。在相同入口速度下，随着偏移率的增大，射流元件壁面压力极大值减小，附壁点下移。归纳出小偏移率情况下无因次附壁点距离与偏移率的经验关系式。该研究为射流元件的尺寸设计提供依据。

Flow analysis on fluidic element of complete fluidic sprinkler

The fluidic element of complete fluidic sprinkler has great influence on the work performance of sprinkler, and the size design is affected by the liquid-gas two-phase inner flow. Two and three dimensional wall attaching offset jets had been numerically simulated by using the volume of fluid (VOF) model, and the wall pressure distribution, velocity decay on the jet centerline, nondimensional reattachment length and liquid-gas two-phase interface position were obtained. For the wall static pressure, the numerical results were consistent with the experimental data. Under the same inlet velocity, the maximal point of wall pressure decreased and the wall attachment point moved down with the increasing of the offset ratio. For the wall attaching jet with small offset ratio, an empirical relationship between the nondimensional reattachment length and offset ratio was summarized. The simulation results are of useful in guiding the fluidic element size design.