高翼螺旋钻杆内部气固两相流动数值分析

Numerical Analysis of Gas-solid Two-phase Flow in High Airfoil Spiral Drill Pipe

为了揭示高翼螺旋钻杆内部气固两相流动规律,采用Euler-Euler模型,对高翼片螺旋钻杆颗粒输运过程进行气固两相流数值计算,得到高翼片螺旋钻杆在不同转速下内部气体和颗粒两相的速度和压力分布规律。数值计算表明,在400 r/min时,截面内部速度分布和压力梯度均匀,转速为600 r/min时,在轴向中间截面产生压力不连续现象,截面内局部发生压力突变,此时内部流场分布紊乱。螺旋钻杆内部压强由进口到出口呈近似线性增长的趋势,转速越高,压力梯度越大,进出口压差也就越大,随着转速增大,螺旋钻杆中间截面速度依次增大,且静止域中速度明显高于旋转域的速度分布。随着转速增大,颗粒相速度依次增大,颗粒相的最大速度小于连续相最大速度。当转速为400 r/min时,颗粒相主要分布在静止域转筒壁面附近,螺旋钻杆内部颗粒分布较少,在惯性力作用下颗粒贴附在螺旋钻杆壁面螺旋推流,颗粒体积分数较为均匀,推流效率较高。当转速为600 r/min时,静止域内部中间位置转筒壁面附近颗粒体积分数较高,螺旋钻杆内部气固两相流动分布极不均匀,表现出显著的气固两相流动不稳定性。

In order to study the relative physical parameters of gas-solid two-phase flow in high-wing spiral drill pipe, Euler-Euler multiphase flow model is used to simulate the whole flow field of the high-wing spiral drill pipe under different rotation speeds.The numerical simulation shows that the internal velocity distribution and pressure gradient are uniform at 400 r/min. When the rotating speed is 600 r/min, the pressure discontinuity occurs in the axial middle section and the pressure in the section changes suddenly. The internal flow field is disordered.The internal pressure of the spiral drill pipe from inlet to outlet is approximately linear increase trend, the higher the speed, the higher the pressure gradient, pressure difference between the inlet and outlet is higher.As the speed increases, the intermediate cross-section velocity increases, and the static field velocity is greater than rotational domain velocity.As the speed increases, the velocity of particle phase increases in turn, and the maximum velocity of the particle phase is less than the maximum velocity of the continuous phase.When the rotating speed is 400 r/min, particles are mostly distributed near the drum wall,that is,static field,while less distributed within the auger. Under the action of inertia force, particles are attached to the spiral drill pipe wall, and the particle volume fraction is more uniform, and the efficiency of the push flow is higher. When the rotating speed is 600 r/min, the volume fraction of particles near the middle of the static field is higher, and the gas-solid two-phase flow distribution inside the spiral drill pipe is extremely nonuniform, showing the significant instability of gas-solid two-phase flow.