【目的】探究旋流式固液两相流泵内流动特征。【方法】基于CFD-DEM(Computational Fluid Dynamics-Discrete Element Method)耦合模型,选用油菜籽颗粒,在不同流量工况和颗粒体积分数下对旋流泵固液两相流场进行数值模拟和试验研究,研究...【目的】探究旋流式固液两相流泵内流动特征。【方法】基于CFD-DEM(Computational Fluid Dynamics-Discrete Element Method)耦合模型,选用油菜籽颗粒,在不同流量工况和颗粒体积分数下对旋流泵固液两相流场进行数值模拟和试验研究,研究旋流式固液两相流泵的内部流动规律及颗粒分布特征。【结果】小流量工况下循环流漩涡特征较明显,进口旋转回流长度较长,对进口来流扰动较大,随着流量增大,循环流影响范围减小;泵内颗粒受到贯通流和循环流的共同作用。管壁中心颗粒受贯通流的影响较大,颗粒穿过无叶腔直接进入叶轮,而靠近管壁的颗粒受循环流的影响较大;叶轮内沿着轴向3个截面处颗粒分布有着较为明显的差异,从叶轮前端面到后盖板,颗粒数量逐渐增多;蜗室内存在一对旋转方向相反的漩涡,在第Ⅴ断面之后前侧涡束逐渐消散,后侧涡束一直旋转至第Ⅷ断面处;在贯通流和循环流的作用下,油菜籽颗粒被旋转回流沿着管壁面带入到进口区域。【结论】循环流的存在导致旋流泵效率较低,但在输送颗粒时循环流起到较大的作用,使得泵输送性能较强;模型泵数值模拟与试验结果基本一致,验证了模拟的可靠性。展开更多
Based on RNG k-ε turbulence model and sliding grid technique, solid-liquid two-phase three-dimensional(3-D) unsteady turbulence of full passage in slurry pump was simulated by means of Fluent software. The effects of...Based on RNG k-ε turbulence model and sliding grid technique, solid-liquid two-phase three-dimensional(3-D) unsteady turbulence of full passage in slurry pump was simulated by means of Fluent software. The effects of unsteady flow characteristics on solid-liquid two-phase flow and pump performance were researched under design condition. The results show that clocking effect has a significant influence on the flow in pump, and the fluctuation of flow velocity and pressure is obvious, particularly near the volute tongue, at the position of small sections of volute and within diffuser. Clocking effect has a more influence on liquid-phase than on solid-phase, and the wake-jet structure of relative velocity of solid-phase is less obvious than liquid-phase near the volute tongue and the impeller passage outlet. The fluctuation of relative velocity of solid-phase flow is 7.6% smaller than liquid-phase flow at the impeller outlet on circular path. Head and radial forces of the impeller are 8.1% and 85.7% of fluctuation, respectively. The results provide a theoretical basis for further research for turbulence, improving efficient, reducing the hydraulic losses and wear. Finally, field tests were carried out to verify the operation and wear of slurry pump.展开更多
文摘【目的】探究旋流式固液两相流泵内流动特征。【方法】基于CFD-DEM(Computational Fluid Dynamics-Discrete Element Method)耦合模型,选用油菜籽颗粒,在不同流量工况和颗粒体积分数下对旋流泵固液两相流场进行数值模拟和试验研究,研究旋流式固液两相流泵的内部流动规律及颗粒分布特征。【结果】小流量工况下循环流漩涡特征较明显,进口旋转回流长度较长,对进口来流扰动较大,随着流量增大,循环流影响范围减小;泵内颗粒受到贯通流和循环流的共同作用。管壁中心颗粒受贯通流的影响较大,颗粒穿过无叶腔直接进入叶轮,而靠近管壁的颗粒受循环流的影响较大;叶轮内沿着轴向3个截面处颗粒分布有着较为明显的差异,从叶轮前端面到后盖板,颗粒数量逐渐增多;蜗室内存在一对旋转方向相反的漩涡,在第Ⅴ断面之后前侧涡束逐渐消散,后侧涡束一直旋转至第Ⅷ断面处;在贯通流和循环流的作用下,油菜籽颗粒被旋转回流沿着管壁面带入到进口区域。【结论】循环流的存在导致旋流泵效率较低,但在输送颗粒时循环流起到较大的作用,使得泵输送性能较强;模型泵数值模拟与试验结果基本一致,验证了模拟的可靠性。
基金Project(51375498)supported by the National Natural Science Foundation of China
文摘Based on RNG k-ε turbulence model and sliding grid technique, solid-liquid two-phase three-dimensional(3-D) unsteady turbulence of full passage in slurry pump was simulated by means of Fluent software. The effects of unsteady flow characteristics on solid-liquid two-phase flow and pump performance were researched under design condition. The results show that clocking effect has a significant influence on the flow in pump, and the fluctuation of flow velocity and pressure is obvious, particularly near the volute tongue, at the position of small sections of volute and within diffuser. Clocking effect has a more influence on liquid-phase than on solid-phase, and the wake-jet structure of relative velocity of solid-phase is less obvious than liquid-phase near the volute tongue and the impeller passage outlet. The fluctuation of relative velocity of solid-phase flow is 7.6% smaller than liquid-phase flow at the impeller outlet on circular path. Head and radial forces of the impeller are 8.1% and 85.7% of fluctuation, respectively. The results provide a theoretical basis for further research for turbulence, improving efficient, reducing the hydraulic losses and wear. Finally, field tests were carried out to verify the operation and wear of slurry pump.
