含粗颗粒固体物料在垂直管流中水击规律

Water Hammer Characteristics of Solid Liquid Two Phase Flow With Coarse Particles in Vertical Pipeline

细颗粒与流体形成的均质或伪均质浆体,可以作为单相流体考虑水击问题.但对于含粗颗粒物料的固液两相流体,由于粗颗粒与流体跟随性较差,水击过程中动量传递特性与细颗粒差异较大;同时,粗颗粒孔隙中含有的气体在水击发生时可以产生较大的压缩变形,改变了颗粒的弹性模量,对水击特性有重要影响.基于浆体水击波速公式,利用试验数据得出粗颗粒与流体的跟随性计算公式,引入颗粒孔隙气体分数修正颗粒弹性模量,推导出了含粗颗粒物料在垂直管流中水击波速公式.将该公式计算结果与锰结核垂直提升管道实验水击波速实测结果比较,二者比较吻合.

The homogeneous or pseudo-horaogeneous slurry of small particles and water can be considered as one-phase flow for analyzing the water hammer problem. But for the two phase flow with coarse particles, there is a big slip velocity between particles and fluid, which possibly cause the change of the momentum transfer characteristic during the water hammer happens. Also, the gas filled in the small hole of particles will be compressed, which will change the particle elastic modulus, and have a significant effect on the water hammer. According to the analyze method of slurry water hamme~：, a new formula has been suggested to calculate the wave speed in vertical pipe flow with low concentration coarse particles based of the above mentioned two factors. The slip velocity can be calculated by the empirical formula from coarse particle hydrodynamic experiments. The particle elastic modulus is revised by using the particle gas percentage parameter. Finally, the new formula is used to calculate the wave speed in vertical flow with coarse particles, and the calculation results are agree with the measured data.