来源：塑料托盘 发布时间：2010年7月31日
塑料托盘搅拌槽/反应器广泛应用于许多工业过程,宏观及微观混合性能是搅拌反应器优化设计的重要组成部分,对于快速复杂反应过程尤为重要。为此,本文从实验和数值模拟两个方塑料托盘面对宏观混合和微观混合进行了深入的研究,研究内容主要包括以下几个方面: 在直径为Φ0.476m的有机玻璃搅拌槽内,采用电导法测定了宏观混合时间,对标准六直叶涡轮桨(DT-6)和三窄叶翼型CBY桨在单层和多层桨操作下的混合时间进行了实验研究。 在FLUENT6.1计算流体力学(CFD)软件平台和网络平行计算系统硬件平台上,首先采用雷诺平均Navier-Stokes方程(RANS)的方法对宏观混合时间进行数值模拟,采用标准k-ε塑料托盘湍流模型和多重参考系法,并将速度场与浓度场方程分开进行求解方法。对于单层桨体系,不论是DT-6桨还是CBY桨,其混合时间的模拟值均与实验结果塑料托盘吻合良好;对于多层桨体系,CBY桨混合时间的模拟值与实验结果相吻合,而双层DT-6桨混合时间的模拟值要比实验结果长约一倍。此外,本文还采用数值模拟的方法研究了不同的示踪剂加料点和监测点位置对混合时间的影响规律。【Abstract】 Agitated reactors/tanks are widely used in many industrial processes. The performances of macromixing and micromixing are of importance to the optimal design of stirred reactor, especially when involved fast complex reactions. In this paper, macromixing and micromixing were studied by experimental approach and using numerical simulations.The mixing time experiments were carried out in a perspex vessel of 0.476m in diameter. The mixing time was measured by using a conductivity probe. Single and multiple standard Rushton disc turbine (DT-6), 3-narrow-blade hydrofoil CBY impeller were used in the experiments to investigate the effect of agitator type on the mixing time.The mixing time in the stirred tank was numerically simulated by using computational fluid dynamics (CFD) package FLUENT6.1 on a PC cluster. Reynolds-averaged Navier-Stokes (RANS) approach with multi-reference frame (MRF) and standard k-ε turbulent model was used in the simulation in the first stage. The momentum and mass equations were computed separately. The mixing time predicted by CFD for the single DT-6, CBY impeller and multiple CBY impellers was in good agreement with the experiment. The mixing time predicted by CFD for the dual DT-6 impellers was about twice experimental. The effects of tracer feeding and detectin