射流泵液固两相流特性三维大涡模拟

为研究射流泵的三维液固两相流动特性,应用计算流体动力学（CFD）方法模拟其内部流动特征.采用LES方法和混合模型对射流泵在输送固体颗粒时的三维流场进行了数值模拟,分析了不同的固体颗粒直径、固相初始体积分数及流量比等参数对射流泵液固两相射流的湍射流场及射流泵基本特性的影响.结果表明：在较小的流量比条件下,固液两相流射流泵的压力比和效率与清水时的差别不大;但是在较大的流量比条件下,随着固相初始体积分数的增大,基本性能曲线与效率均下降,且流量比和固相初始体积分数越大时,其下降幅度越大;在固相初始体积分数和固相颗粒直径一定时,流量比越大,充分混合后的含砂体积分数将随之增大.固体颗粒直径越大,则越容易产生局部体积分布集中的现象,易在射流泵内形成堵塞.研究结果为工程实际应用提供了一定的技术支持.

Performance of liquid-solid two-phase flow in jet pump by LES

To find out the flow characteristic of 3D liquid-solid two-phase flow in a jet pump,the large eddy simulation（LES） was used to calculate the flow field in the jet pump.The mixture model was adopted to treat the liquid-solid two-phase interaction.Influences of solid-phase initial volume fraction and granular diameter as well as flow ratio on the jet pump characteristics were analyzed.The results show that the pressure ratio and efficiency of pumping solid-liquid two phase fluids have a minor diffe-rence with those of delivering water at a small flow rate ratio.With increasing flow rate ratio,however,the pressure ratio and efficiency for solid-liquid two phase fluids are decreased a lot compared with those for water when the granule density is increased.For a constant initial solid volume fraction and granular diameter,the solid volume fraction is increased with the flow ratio after a fully mixing takes place.The larger the granular diameter,the more easily the solid volume fraction distribution becomes concentrated.The results of the study lay a foundation for particular applications of engineering.