Particulate aggregation through a modulated annular one-dimensional acoustic field at resonant frequencies--颗粒学报PARTICUOLOGY

Qiao, Z., Pan, X., Liang, S., Bi, X., Wang, J., Xie, W., . . . Li, S. (2021). Particulate aggregation through a modulated annular one-dimensional acoustic field at resonant frequencies. Particuology, 57, 82-94. https://doi.org/10.1016/j.partic.2020.11.009

Particulate aggregation through a modulated annular one-dimensional acoustic field at resonant frequencies

Zhenghui Qiao ^{a b *}, Xiaojun Pan^a, Shaohua Liang ^a, Xiaolong Bi ^a, Juan Wang a, Wei Xie a, Kang Wang ^a, Yanwen Wang ^a, Jun Fang ^a, Xuefei Zhu ^a, Shaoxin Sun ^a, Shaohui Li ^b

a College of Energy and Power Engineering, Nanjing Institute of Technology, Nanjing 211167, China
b Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China

10.1016/j.partic.2020.11.009

Volume 57, August 2021, Pages 82-94

Received 6 August 2020, Revised 14 November 2020, Accepted 22 November 2020, Available online 23 February 2021, Version of Record 23 February 2021.

E-mail: qiaozhenghui@njit.edu.cn

Highlights

• Aggregation of smoke particulates in a modulated annular acoustic field is studied.

• Visualization and analysis of complex acoustic-particulate-fluid system are performed.

• Collective aggregation and fragmentation process of smoke particulates are demonstrated.

• Acoustic radiation force and secondary radiation force explain the process control.

• Physical parameter changes in the particles in different environments cause the behaviors.

Abstract

The visualization and analysis of a novel acoustic-particulate system is the objective of this study. The system is composed of rice-husk fired smoke particulates (36.7 nm–840 μm) and one annular resonant circular-tube waveguide contrarily coupled with two sound sources. The collective interaction behavior process of smoke particulates in an inhomogeneous acoustic field is displayed during an experiment and a simulation. The result shows that the aggregation and fragmentation of particles under a change in resonant frequencies and sound pressure amplitude is extremely complex. This complex process consists of dynamically tuning the particle characteristics to attain stripes shaped like thin-films/umbrellas and clusters with volume-change/fragmentation. The balanced modulation of the acoustic radiation force and secondary radiation force to alter the particle characteristics (size and stack density) is verified to be the control mechanism of the particle system. The intermediate variable of the process control is the acoustic contrast factor (Ф) related to the physical characteristics of the growing particulates. The value plus-minus alternation of Ф results in different particulate processes. This study can enhance the application of aerodynamic acoustic-particulate-fluid systems for environment protection, energy fuel conversion, and industrial production.

Graphical abstract

Keywords

Acoustic aggregation; Porous particulates; Secondary radiation force; Acoustic radiation force; Stripe pattern; Inhomogeneous field

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