迷宫螺旋泵水煤浆输送的CFD数值模拟及其内部磨损的初步探讨

发布时间：2018-05-23 20:14

本文选题：迷宫螺旋泵 + 固液两相流　；参考：《北京化工大学》2011年硕士论文

【摘要】：本文简要介绍了水煤浆技术的发展以及几种水煤浆输送泵的特点,重点分析了迷宫螺旋泵的特点及其发展概况。为探明迷宫螺旋泵内部固液两相流动的规律,本文选用MLB-170-0.5型双端迷宫螺旋泵为研究对象,应用FLUENT计算流体力学分析软件及RNGκ-ε模型,对水煤浆高速迷宫螺旋泵内部流场进行数值模拟和仿真,得到了泵内部压力、速度、固相体积分数、湍流强度和剪切应力的分布情况,同时也对其内部的颗粒磨损机理进行了初步探讨。迷宫螺旋泵内固液两相流动的规律：压力从进口到出口是逐渐增大的；在中间螺旋段部分,速度的轴向分布是一样的,在周向上随着轴径的减小逐渐增大,在转子螺纹槽处达到最大；固相体积分数分布在径向值相同的不同区域是有差别的,沿着螺旋半径增大的方向逐渐增大,定子螺槽部分固相体积分数达到最大；螺纹定、转子间隙区域的湍动程度最强烈,定、转子螺纹槽根处的流体湍动相对比较平缓；距定、转子工作面较近的地方流体对壁面所产生的剪切应力比较大,且固体颗粒相煤较液相水对工作面所产生的剪切应力更大。体积分数相同、粒径不同和粒径相同、体积分数不同两种介质下固相体积分数和粒径对两相流规律的影响：粒径相同时,固相体积分数越大,出口压力越大,速度分布和湍流强度均没有明显变化,液相水的剪切应力减小,固相煤的剪切应力增大；固相体积分数相同时,颗粒粒径越大,压力和湍流强度不变,颗粒相速度减小,液相水剪切应力增大,固相煤剪切应力减小。由模拟结果可知螺旋定子部分的固体颗粒体积含量较高,转子螺槽部分颗粒的速度较高,由磨损率公式初步预测螺旋转子受到颗粒的磨损比较严重,这就对转子的材料和加工工艺有更高的要求。通过对水煤浆固液两相流的数值模拟,得到了定转子内部流场的流动情况,为迷宫螺旋泵的进一步研究设计提供了理论依据。
[Abstract]:This paper briefly introduces the development of coal-water slurry technology and the characteristics of several kinds of water-coal slurry conveying pumps, and emphatically analyzes the characteristics and development of labyrinth screw pumps. In order to find out the law of solid-liquid two-phase flow in labyrinth screw pump, MLB-170-0.5 type double-end labyrinth spiral pump is chosen as the research object, FLUENT computational fluid dynamics analysis software and RNG 魏-蔚 model are used. Numerical simulation and simulation of flow field in high speed labyrinth spiral pump of coal water slurry are carried out, and the distribution of internal pressure, velocity, solid phase volume fraction, turbulence intensity and shear stress are obtained. At the same time, the mechanism of particle wear inside is also discussed. The law of solid-liquid two-phase flow in labyrinth spiral pump: the pressure increases gradually from the inlet to the outlet, the axial distribution of velocity is the same in the middle spiral section, and the axial velocity increases gradually with the decrease of axial diameter in the circumferential direction. The distribution of solid phase volume fraction in different regions with the same radial value is different, and gradually increases along the direction of spiral radius increase, the stator screw groove part solid phase volume fraction reaches the maximum. The turbulence in the rotor clearance region is the strongest, the fluid turbulence at the root of the screw groove of the rotor is relatively gentle, and the shear stress on the wall caused by the fluid closer to the rotor face is greater than that of the stator. And the shear stress of solid granular coal is larger than that of liquid water. The effect of solid volume fraction and particle size on the law of two-phase flow under the same volume fraction, different particle size and same particle size: when the particle size is the same, the larger the solid volume fraction is, the greater the outlet pressure is. The velocity distribution and turbulence intensity have no obvious change, the shear stress of liquid water decreases, the shear stress of solid coal increases, the particle size increases with the same solid volume fraction, the pressure and turbulence intensity remain constant, the particle phase velocity decreases. The liquid water shear stress increases and the solid coal shear stress decreases. According to the simulation results, the volume content of solid particles in the spiral stator is higher, and the velocity of the solids in the rotor spiral groove is higher. The wear rate formula is used to predict that the spiral rotor is seriously worn by the particles. This has higher requirements for rotor materials and processing technology. Through the numerical simulation of the solid-liquid two-phase flow of coal water slurry, the flow field in the stator and rotor is obtained, which provides a theoretical basis for the further study and design of the labyrinth screw pump.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH32

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