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
The application of small diameter arterial grafts is limited due to the fact of relatively poor long-time patency which is caused by thrombosis formation in the short term and intimal hyperplasia(IH) in the medium and...The application of small diameter arterial grafts is limited due to the fact of relatively poor long-time patency which is caused by thrombosis formation in the short term and intimal hyperplasia(IH) in the medium and long term.Thrombosis,obstructing the flow of blood展开更多
The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe traverses.PIV measurements have alread...The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe traverses.PIV measurements have already been performed at middle height inside one diffuser channel passage for a given speed of rotation and various mass flow rates.These results have been already presented in several previous communications.New experiments have been performed using a three-hole pressure probe traverses from hub to shroud diffuser width at different radial locations between the two diffuser geometrical throats.Numerical simulations are also realized with the commercial codes Star CCM+7.02.011 and CFX.Frozen rotor and fully unsteady calculations of the whole pump have been performed.Comparisons between numerical results,previous experimental PIV results and new probe traverses one's are presented and discussed for one mass flow rate.In this respect,a first attempt to take into account fluid leakages between the rotating and fixed part of the pump has been checked since it may affects the real flow structure inside the diffuser.展开更多
为了快速、准确分析螺旋桨滑流对增升装置的影响,采用实桨非定常方法(full blades method,FBM)和定常动量激励盘方法(actuator disk method,ADM),数值计算分析了前进比J=0.7、1.0,攻角α=–4°~24°工况下螺旋桨滑流对高升力构...为了快速、准确分析螺旋桨滑流对增升装置的影响,采用实桨非定常方法(full blades method,FBM)和定常动量激励盘方法(actuator disk method,ADM),数值计算分析了前进比J=0.7、1.0,攻角α=–4°~24°工况下螺旋桨滑流对高升力构型的影响。研究表明:虽然从单独螺旋桨获取的时均化激励盘载荷分布与从高升力构型螺旋桨获取的存在局部差异,但将来源不同的激励盘载荷应用于ADM计算时,所得高升力构型的压力分布、升阻力结果基本一致,全机升力系数差异不超过4.3%,阻力系数偏差小于5.4%,说明采用单独螺旋桨获取激励盘载荷对全机气动力计算影响不大,从而避免了复杂的网格生成。ADM将非定常计算转化为定常计算,在保持网格量相当(3300万)的条件下,其计算结果与FBM结果在失速前(α<20°时)基本吻合,同时计算核时约降低至FBM的1/18(170/3100)。因此ADM方法能够高效、合理评估出螺旋桨滑流对增升装置产生的影响。展开更多
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.
文摘The application of small diameter arterial grafts is limited due to the fact of relatively poor long-time patency which is caused by thrombosis formation in the short term and intimal hyperplasia(IH) in the medium and long term.Thrombosis,obstructing the flow of blood
文摘The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe traverses.PIV measurements have already been performed at middle height inside one diffuser channel passage for a given speed of rotation and various mass flow rates.These results have been already presented in several previous communications.New experiments have been performed using a three-hole pressure probe traverses from hub to shroud diffuser width at different radial locations between the two diffuser geometrical throats.Numerical simulations are also realized with the commercial codes Star CCM+7.02.011 and CFX.Frozen rotor and fully unsteady calculations of the whole pump have been performed.Comparisons between numerical results,previous experimental PIV results and new probe traverses one's are presented and discussed for one mass flow rate.In this respect,a first attempt to take into account fluid leakages between the rotating and fixed part of the pump has been checked since it may affects the real flow structure inside the diffuser.
文摘为了快速、准确分析螺旋桨滑流对增升装置的影响,采用实桨非定常方法(full blades method,FBM)和定常动量激励盘方法(actuator disk method,ADM),数值计算分析了前进比J=0.7、1.0,攻角α=–4°~24°工况下螺旋桨滑流对高升力构型的影响。研究表明:虽然从单独螺旋桨获取的时均化激励盘载荷分布与从高升力构型螺旋桨获取的存在局部差异,但将来源不同的激励盘载荷应用于ADM计算时,所得高升力构型的压力分布、升阻力结果基本一致,全机升力系数差异不超过4.3%,阻力系数偏差小于5.4%,说明采用单独螺旋桨获取激励盘载荷对全机气动力计算影响不大,从而避免了复杂的网格生成。ADM将非定常计算转化为定常计算,在保持网格量相当(3300万)的条件下,其计算结果与FBM结果在失速前(α<20°时)基本吻合,同时计算核时约降低至FBM的1/18(170/3100)。因此ADM方法能够高效、合理评估出螺旋桨滑流对增升装置产生的影响。
