Modeling and numerical investigation of acoustic cavitation with applications in sonochemistry
Modeling and numerical investigation of acoustic cavitation with applications in sonochemistry
复制标题
声空化的建模和数值研究及其在声化学中的应用
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
R. Jamshidi
中科院分区：
文献类型：
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作者：
R. Jamshidi
本论文的重点是提供更详细、更可靠的描述和模型来量化声化学反应器中流动与声场、空化气泡和能量耗散之间的相互关系。模拟这种现象的主要问题是必须同时考虑不同的时间和空间尺度。该研究的起点是在锥形反应器中使用线性化假设对空化活动进行数值研究。研究了波传播建模的不同工作假设、空化气泡引起的压力衰减以及波频率、输入功率和反应器几何形状的影响。基于频域中的线性化波动方程，开发了一种快速且鲁棒的数值方法，并将其应用于 COMSOL Multiphysics 软件中。结果表明，超声源的频率和功率可以根据空化的位置和强度进行优化。此外，模拟壁边界吸收特性的不同边界条件会导致明显不同的波型。基于第一部分中进行的准线性分析，该方法得到了增强，以考虑更严格的物理模型，以解释空化流中气泡的衰减效应。首先，采用能量守恒方法，考虑气泡周围液体的可压缩性，开发了声波非线性阻尼的新模型。非线性阻尼模型中引入了不同类型的阻尼，并说明了它们的来源。其次，开发了一种统一的计算方法来耦合湍流中空化气泡的动力学和波传播。该方法基于 OpenFOAM 软件库，可以有效地实现不同的模型和数值方案。为了研究气泡的结构，开发了一种针对不同半径气泡的欧拉拉格朗日方法。此外，还考虑了气泡之间的相互作用（碰撞和二次毕克尼斯力的影响）以及气泡群和声波之间的相互作用（非线性阻尼和一次毕克尼斯力）。为了验证和确认本方法，选择了几个通用测试用例和实验配置进行比较。结果表明，求解器可以精确地预测气泡的结构、气泡与声波的相互作用以及声流产生的流场。因此，该方法有利于具有复杂几何形状（包括基本物理原理）的三维声化学反应器的数值模拟。
The focus of the present thesis is to provide more detailed and reliable desc riptions and models to quantify the mutual relation between flow and sound field, cavitation bubbles and ener gy dissipation in sonochemical reactors. The major problem regarding the simulation of such a phenome non is that different time and spatial scales have to be considered simultaneously. The starting point of th e research is the numerical investigation of the cavitational activity using linearized assumptions in a conica l shape reactor. Different working assumptions for modeling of the wave propagation, attenuation of pr essu e due to cavitation bubbles and the influence of wave frequency, input power and reactor ge ometry are examined. Based on the linearized wave equation in the frequency domain, a fast and robust nume rical method is developed and applied in the COMSOL Multiphysics software. Results illustrate that both, the fr equency and power of the ultrasound source may be optimized with respect to the location and strength of cavitation. In addition, different boundary conditions to model the absorbing properties of wall boundaries, lead to significantly different wave patterns. Based on the quasi-linear analysis performed in the first part, the approa ch is enhanced to account for the attenuating effect of gas bubbles in cavitating flows considering more rigor ous physical models. Firstly, using an energy conservation approach, a new model is developed for nonlinear damping of acoustic waves considering the compressibility of the liquid around bubbles. Different type s of damping are introduced into the nonlinear damping models and their sources are illustrated. Secondly, a unified computational method is developed to couple the dynamics of cavitating bubbles and wave pro pagation in a turbulent flow. The approach is based on the OpenFOAM software library, which a llows implementing different models and numerical schemes in an efficient way. To investigate the structur e of bubbles, an EulerianLagrangian approach for bubbles with varying radii is developed. Fur thermore, the interaction among bubbles (collision and the effect of secondary Bjerknes force) and a lso between the bubbles swarm and acoustic waves (nonlinear damping and primary Bjerknes force) are con sidered. To verify and validate the present approach, several generic test cases as well as exper imental configurations are selected for comparison. Results show that the solver predicts the structure of bubbles , their interaction with acoustic waves and the flow field due to acoustic streaming in a precise way. Therefo re, the approach is beneficial for numerical simulation of three-dimensional sonochemical reactors with co mplex geometry, including the essential physics.
影响因子：
2.4
作者：
Doinikov, Alexander A.;Dayton, Paul A.
通讯作者：
Dayton, Paul A.
影响因子：
2.4
作者：
Ando, Keita;Colonius, Tim;Brennen, Christopher E.
通讯作者：
Brennen, Christopher E.