HD型石油化工流程泵内部固液两相分布规律

为了研究HD型石油化工流程泵首级双吸式叶轮、双蜗壳流道内部固液两相流动规律,应用计算流体动力学软件Fluent,基于雷诺时均N-S方程和k-ε紊流模型,采用SIMPLEC算法进行压力速度耦合,对双吸式叶轮、双蜗壳内的流场进行数值计算.同时分析不同初始固相体积分数以及不同颗粒直径条件下,叶轮及双蜗壳内的固相体积分数分布的变化规律,得到与单吸式叶轮、单蜗壳不同的流动规律.计算结果表明:在双吸式叶轮内,随着初始固相体积分数的增大,固相体积分数分布变化很大且变化规律明显,靠近吸力面侧固相体积分数较大,靠近压力面侧则较低;固体颗粒在双吸式叶轮中有向叶片吸力面侧运动的趋势,且随着粒径的增大颗粒会向叶片吸力面运动,但固相体积分数分布变化不大;在双蜗壳流道内,固相体积分数分布不均匀,在第一断面至第八断面固相体积分数相对较大,在扩散段外侧体积分数较大,内侧体积分数较小,固体颗粒有向外侧壁面运动趋势,固相体积分数显著较大.

Solid volume concentration distribution of solid-liquid two-phase flow in HD type petrol-chemical process pump

The steady solid-liquid two-phase flow field in the fist stage of a HD type petrol-chemical process pump is simulated with CFD software by employing the Reynolds Averaged Navier- Stokes equations and the standard k- ε turbulence model as well as SIMPLEC algorithm to explore the distribution pattern of solid particle volume concentration in the double-suction impeller and double-channel volute of the first stage of the pump. The two-phase flow is subject to different solid bulk volume concentrations and particle diameters. The results show that solid volume concentration distribution becomes non-uniform in the double-suction impeller but exhibits a noticed regular pattern with increasing solid particle bulk concentration at constant particle diameter,that is,the concentration is higher near the blade suction side than the pressure side. Besides,solid particles have a tendency to move to the blade suction side. Moreover,the particles move towards the suction side with increasing particle diameter at fixed bulk concentration; however,the non-uniformity of solid concentration remains nearly unchanged. In the double-channel volute,solid concentration is distributed unevenly as well; particularly,the local solid particle concentration is increased from section 1 to section 8. Additionally,in the diffuser of volute,the concentration is higher nearly the diffuser side wall with tongue than the opposite side wall of the tongue. The solid particles with large diameter tend to move towards the opposite side wall of the tongue,causing a relatively higher concentration there.