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
Proper room and pillar sizes are both critical factors for safe mining and high ore recovery rate in shrinkage stoping mining of underground metal mines.The rock masses of Tangdan copper mine of China are fractured,wh...Proper room and pillar sizes are both critical factors for safe mining and high ore recovery rate in shrinkage stoping mining of underground metal mines.The rock masses of Tangdan copper mine of China are fractured,which needs much reinforcement and support prior to mining.Cement-sodium silicate grout technology was selected,then its related parameters such as grout pressure,diffusion radius and time were calculated and proposed.In order to test the effect of the pressured grout in the fractured No.4 ore block,field experiments were conducted.To optimize stoping configuration,three-dimensional numerical simulation with ANSYS and FLAC 3 D softwares was proposed.The results show that the drilling porosity and mechanical properties of the rock masses are increased obviously.After grout,ore recovery rate is increased by 10.2%employing the newly designed stoping configuration compared with the previous.Last,analyzed from the surface movements,roof subsidence and the maximum principal stress of the pillars,the mining safety is probable of being ensured.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
以石槽村煤矿宝塔山砂岩含水层为工程背景,构建了含水层三维可视化模型,通过单孔、多孔非稳定流模型对该可视化模型进行验证,并对顶板泄水点位置反演预估。结果表明:采区顶板群孔非稳定流模型数据与观测孔放水实测数据拟合性好,模型可...以石槽村煤矿宝塔山砂岩含水层为工程背景,构建了含水层三维可视化模型,通过单孔、多孔非稳定流模型对该可视化模型进行验证,并对顶板泄水点位置反演预估。结果表明:采区顶板群孔非稳定流模型数据与观测孔放水实测数据拟合性好,模型可信度高;含水层数值重构最优解为6个分区,即Ⅰ高渗中储水区、Ⅱ中渗高储水区、Ⅲ高渗高储水区、Ⅳ低渗中储水区、Ⅴ低渗低储水区、Ⅵ中渗中储水区;井下泄水点位置在G1-1观测点和F1-3观测点之间,泄水量为150~200 m 3/d。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
基金Projects(51374034,51674012)supported by the National Natural Science Foundation of ChinaProject(2013BAB02B05)supported by the China National Science and Technology Support Program during the 12th Five-Year Plan Period
文摘Proper room and pillar sizes are both critical factors for safe mining and high ore recovery rate in shrinkage stoping mining of underground metal mines.The rock masses of Tangdan copper mine of China are fractured,which needs much reinforcement and support prior to mining.Cement-sodium silicate grout technology was selected,then its related parameters such as grout pressure,diffusion radius and time were calculated and proposed.In order to test the effect of the pressured grout in the fractured No.4 ore block,field experiments were conducted.To optimize stoping configuration,three-dimensional numerical simulation with ANSYS and FLAC 3 D softwares was proposed.The results show that the drilling porosity and mechanical properties of the rock masses are increased obviously.After grout,ore recovery rate is increased by 10.2%employing the newly designed stoping configuration compared with the previous.Last,analyzed from the surface movements,roof subsidence and the maximum principal stress of the pillars,the mining safety is probable of being ensured.
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。
文摘以石槽村煤矿宝塔山砂岩含水层为工程背景,构建了含水层三维可视化模型,通过单孔、多孔非稳定流模型对该可视化模型进行验证,并对顶板泄水点位置反演预估。结果表明:采区顶板群孔非稳定流模型数据与观测孔放水实测数据拟合性好,模型可信度高;含水层数值重构最优解为6个分区,即Ⅰ高渗中储水区、Ⅱ中渗高储水区、Ⅲ高渗高储水区、Ⅳ低渗中储水区、Ⅴ低渗低储水区、Ⅵ中渗中储水区;井下泄水点位置在G1-1观测点和F1-3观测点之间,泄水量为150~200 m 3/d。
