化工学报2019，Vol.70Issue(5)：1693-1701,9.DOI:10.11949/j.issn.0438-1157.20181179
刚柔组合桨强化粉煤灰酸浸搅拌槽内固液混沌混合
Chaotic mixing process of fly ash in acid leaching tank intensified by rigid-flexible impeller
摘要
Abstract
In the traditional fly ash aluminizing process, the acid immersion stirring tank adopts a rigid stirring paddle. Due to the limited pumping capacity of rigid impellers, some problems such as settlement of solid particles, deficiently of chaotic, and low efficiency of mixing in this process often occur in solid-liquid mixing processes. Thus, the rigid-flexible impeller was adopted to enhance solid-liquid chaotic mixing behavior in acid leaching process. In a fly ash-water system with a solids concentration of 30%, the chaotic mixing characteristics and energy dissipation were investigated in STRs equipped with rigid-flexible impeller. Torque sensor was employed to collect the torque time series signal. The largest Lyapunov exponents and the multi-scale entropy were compiled and calculated by Matlab to indicate the degree of chaotic mixing based on the torque time series signal. Meanwhile, the power consumption per unit volume was used to characterize the stirred reactor power characteristics. The effects of impeller types, rotation speed, flexible piece width/length, and impeller off-bottom clearance on chaotic mixing behavior were taken into consideration in the solid-liquid mixing processes. The results showed that the rigid-flexible impeller could effectively promote the chaotic mixing and reduce the accumulation of solid particles at the bottom of STRs in the fly ash-water system. Largest Lyapunov exponents of the system reached the maximum value of 0.0645 and multi-scale entropy was bigger than that of other conditions at the rotation speed of 120 r/min, the off-bottom clearance of T/4, the flexible piece length of 1.2H1 and width of D/8. The power consumption increases exponentially with the increase of rotation speed.关键词
刚柔组合桨/粉煤灰/混沌混合/最大Lyapunov指数/多尺度熵Key words
rigid-flexible impeller/coal ash/chaotic mixing/largest Lyapunov exponents/multi-scale entropy分类
化学化工引用本文复制引用
熊黠,刘作华,谷德银,邱发成,王靓,陶长元,王运东..刚柔组合桨强化粉煤灰酸浸搅拌槽内固液混沌混合[J].化工学报,2019,70(5):1693-1701,9.基金项目
国家重点研发计划项目(2017YFB0603105) （2017YFB0603105）
国家自然科学基金项目(21636004) （21636004）
重庆市研究生科研创新项目(CYS18031) （CYS18031）
重庆市社会事业与民生保障科技创新专项项目(cstc2017shmsA90016) （cstc2017shmsA90016）
国家科技支撑计划项目(2015BAB17B01) （2015BAB17B01）
