Numerical calculation of particle and bubble dispersion in a fluid-phase resonance mixer

液相共振混合器中颗粒和气泡分散的数值计算

• 批准号: 254590687
• 负责人: Professor Dr.-Ing. Martin Sommerfeld
• 金额: --
• 依托单位: Hochschule Merseburg
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/254590687?language=en
• 关键词: Numerical; calculation; particle; bubble; dispersion

In preliminary investigations it could be demonstrated that the fluid-phase resonance mixer (FPR-mixer) is suitable for realising effective fluid mixing. For this purpose, both numerical calculations (with OpenFOAM) as well as experiments were conducted. In the present proposal it is intended to prove the suitability of the FPR-mixer for particle and bubble dispersion. The numerical calculations shall be conducted by the Euler (LES)/Lagrange approach using again OpenFOAM.For allowing a realistic numerical calculation of particle and bubble dispersion in a liquid phase, however, the dynamics of the dispersed phase shall be analysed considering all relevant fluid forces. This implies an extension of the equation of motion accounting for drag, gravity/buoyancy, pressure term, added mass, basset-force and slip-shear lift. The coefficients for added mass and Basset term shall be taken according to Odar & Hamilton (1964) as well as those recently suggested by Michaelides & Roig (2011), which depends for the Basset term on the Strouhal number. Results obtained with both coefficients will be compared. Moreover, the importance of the different unsteady forces will be analyzed in detail and the simulation results will be compared with measurements in the FPR-mixer. These studies will be done in dependence of the Stokes-number (depending on particle- and bubble-size, density ratio and pulsation frequency) and provide corresponding recommendations regarding the importance of the unsteady forces.On the basis of these developments, numerical calculations of the dispersion of particles and bubbles are planned in order to optimise geometry (e.g. diameter of immersed pipe and bottom clearance) and operational conditions (e.g. oscillation frequency) of the FPR-mixer. The objective is achieving a homogeneous distribution of particles or bubbles as much as possible. For identifying these conditions the Stokes-number shall be varied over the relevant range. In addition the effect of the unsteady forces on the dispersion result in a technical process will be analysed in detail for the first time.For validating the numerical calculations, experiments for selected conditions will be conducted. The simultaneous measurement of the velocity fields for continuous and dispersed phase will be realised by using fluorescing tracer particles in conjunction with the application of PIV (particle image velocimetry) as well as PTV (particle tracking velocimetry). By using two CCD-cameras with appropriate optical filters both phases are reliably distinguished. In addition instantaneous dispersed phase concentration fields will be estimated.

初步研究表明，流体相共振混合器(FPR-Mixer)适用于实现有效的流体混合。为此，进行了数值计算(使用OpenFOAM)和实验。在本方案中，旨在证明FPR混合器对颗粒和气泡分散的适用性。数值计算应由欧拉(LES)/拉格朗日方法进行，并再次使用OpenFOAM。然而，为了能够对颗粒和气泡在液体中的扩散进行真实的数值计算，应考虑所有相关的流体力来分析分散相的动力学。这意味着考虑了阻力、重力/浮力、压力项、附加质量、基座力和滑移-剪切升力的运动方程的扩展。附加质量和Basset项的系数应根据Odar&Hamilton(1964)以及Michaelides&Roig(2011)最近建议的系数来计算，后者取决于Strouhal数。用这两个系数得到的结果将被比较。此外，还将详细分析不同非定常力的重要性，并将模拟结果与FPR混合器中的测量结果进行比较。这些研究将根据斯托克斯数(取决于颗粒和气泡的大小、密度比和脉动频率)进行，并就非定常作用力的重要性提供相应的建议。在这些发展的基础上，计划对颗粒和气泡的扩散进行数值计算，以优化FPR混合器的几何结构(如沉管直径和底部间隙)和操作条件(如振荡频率)。其目标是尽可能实现颗粒或气泡的均匀分布。为了识别这些条件，斯托克斯数应在相关范围内变化。此外，还将首次详细分析工艺过程中非恒定力对分散结果的影响。为了验证数值计算的有效性，将在选定的条件下进行实验。结合PIV(粒子图像测速仪)和PTV(粒子跟踪测速仪)的应用，将实现对连续相和分散相速度场的同时测量。通过使用两个带有适当滤光片的CCD摄像机，可以可靠地区分这两个相位。此外，还将估计瞬时分散相浓度场。

项目成果

Numerical and experimental analysis of Fluid Phase Resonance mixers

液相共振混合器的数值和实验分析

• DOI: 10.1016/j.ces.2017.08.012
• 发表时间: 2017
• 期刊: Chemical Engineering Science
• 影响因子: 4.7
• 作者: Schmalfuß;Sommerfeld
• 通讯作者: Sommerfeld