CAJ | 학술논문

采用粒子图像测速和分析技术,研究了固-液方槽体系中液相湍流特性.测得固体颗粒浓度从0增加到0.9%(ψ)时,液相在桨叶区和近壁区的湍流流场分布.结果表明,随固体颗粒浓度增加到0.9%(ψ),液相轴向平均速度<v>持续减小,在桨叶区其衰减幅度△v~*与固体颗粒浓度C_v的关系为△v~*∝C_v~(0.776),近壁区为△v~*∝C_v~(1.474).桨叶区湍流动能分布较复杂,与单相相比,固体颗粒浓度从0增加到0.5%(ψ)时,湍流动能增强:固体颗粒浓度从0.5%增加到0.9%(ψ)时,湍流动能减小.在整个测量区域,随固体颗粒浓度增加,平均湍流动能呈减小趋势,拟合平均湍流动能k与固体颗粒浓度的关系为(k)/v_(tip)~2∝C_v~(-0.073),平均湍流动能耗散率呈增长趋势,拟合平均湍流动能耗散速率ε与固体颗粒浓度的关系为(ε)/(D~2N~3)∝C_v~(1.113).
채용입자도상측속화분석기술,연구료고-액방조체계중액상단류특성.측득고체과립농도종0증가도0.9%(ψ)시,액상재장협구화근벽구적단류류장분포.결과표명,수고체과립농도증가도0.9%(ψ),액상축향평균속도<v>지속감소,재장협구기쇠감폭도△v~*여고체과립농도C_v적관계위△v~*∝C_v~(0.776),근벽구위△v~*∝C_v~(1.474).장협구단류동능분포교복잡,여단상상비,고체과립농도종0증가도0.5%(ψ)시,단류동능증강:고체과립농도종0.5%증가도0.9%(ψ)시,단류동능감소.재정개측량구역,수고체과립농도증가,평균단류동능정감소추세,의합평균단류동능k여고체과립농도적관계위(k)/v_(tip)~2∝C_v~(-0.073),평균단류동능모산솔정증장추세,의합평균단류동능모산속솔ε여고체과립농도적관계위(ε)/(D~2N~3)∝C_v~(1.113).
Two-dimensional particle image velocimetry and digital image analysis were used to quantify the hydrodynamics of solid-liquid suspension in a square stirred tank. Solid particle spheres with 750 μm diameter were employed as the dispersed phase with up to volumetric concentration of 0.9%(ψ) in water. The magnitude of continuous phase mean axial velocity decreased in the impeller and near-wall regions, as the solid concentration increased, the relationship of the velocity drop and the particle concentration could be respectively described as △v~*∝C_v~(0.776)and △v~*∝C_v~(1.474). The turbulent kinetic energy distribution of the continuous phase was complex, because it increased in the impeller region with the solid volumetric concentration up to 0.5%(ψ) and decreased above that. The average turbulent kinetic energy remained decreased as the particle concentration increasing from 0.2% to 0.9%(ψ), the relationship could be described as ((k)/v_(tip)~2∝C_v~(-0.073)). By contrast, the average turbulent kinetic energy dissipation rate of the continuous phase was more enhanced than that in the single phase flow, which could be described as (ε)/(D~2N~3)∝C_v~(1.113).