强声波作用下煤颗粒周围气体的振荡流动特性

计算物理 ›› 2017, Vol. 34 ›› Issue (4): 425-436.

强声波作用下煤颗粒周围气体的振荡流动特性

许伟龙^1,2, 姜根山², 安连锁¹, 刘月超^1,2, 吴亚攀²

1. 华北电力大学能源动力与机械工程学院, 北京 102206;
2. 华北电力大学数理系, 保定 071003

收稿日期:2016-05-10 修回日期:2016-08-31 出版日期:2017-07-25 发布日期:2017-07-25
通讯作者: 姜根山,教授,博士生导师,研究方向:锅炉声学理论及应用,E-mail:gsjiang@ncepu.edu.cn
作者简介:许伟龙,博士研究生,主要研究方向:声波在炉内的传播特性及声效应研究,E-mail:xuweilong@ncepu.edu.cn
基金资助:
国家自然科学基金（11474091，11674093和11274111）；河北省自然科学基金（A2015502077）；中央高校基本科研业务费专项资金（2015XS105）资助项目

Oscillating Flow Characteristics Around Coal Particle in High Intensity Sound Field

XU Weilong^1,2, JIANG Genshan², AN Liansuo¹, LIU Yuechao^1,2, WU Yapan²

1. School of Energy, Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, China;
2. Faculty of Mathematics and Physics, North China Electric Power University, Baoding 071003, China

Received:2016-05-10 Revised:2016-08-31 Online:2017-07-25 Published:2017-07-25

摘要/Abstract

摘要： 根据二维非稳态层流的质量和动量守恒方程，研究强声波作用下煤颗粒周围气体的振荡流动特性.入射波的振幅远大于颗粒特征长度，声雷诺数小于20.根据通用微分方程的解，详细分析不同声雷诺数与斯特劳哈尔数下，颗粒壁面的流场分布、轴向压力梯度、切向应力及分离角的分布，发现在低频（~50 Hz）时，颗粒壁面轴向压力梯度、切向应力及流动分离角的分布主要受曲率效应影响，其变化规律与振荡速度的幅值变化相对应；在高频时（~5 000 Hz），颗粒壁面轴向压力梯度、切向应力及流动分离角的分布同时受到曲率效应和流动加速度的影响.为进一步研究强声波强化煤颗粒燃烧提供理论基础.

关键词: 强声波, 振荡流, 煤颗粒, 流动分离

Abstract: To study flow field distribution characteristics around a pulverized coal particle in high intensity acoustic field with sonic frequencies, two-dimensional unsteady mass and momentum conservations for laminar flow in spherical coordinates were developed with actual parameters of power plant boiler. Displacement amplitude of incident sound wave is greater than characteristic length of particles, and acoustic Reynolds number is less than 20. Velocity field, axial pressure gradient, shear stress and flow separation angle around particle were analyzed at different acoustic Reynolds numbers and Strouhal numbers. It is found that axial pressure gradient, shear stress and separation angle are proportional to magnitude of sound at low frequency (~50Hz). However, they are different due to combined effects of curvature and flow acceleration at high frequency (~5 000 Hz). It provides theoretical foundation for further research on acoustic enhancement of heat and mass transfer in power plant boiler.

Key words: high intensity sound, oscillating flow, coal particle, flow separation

中图分类号:

TK224.1

许伟龙, 姜根山, 安连锁, 刘月超, 吴亚攀. 强声波作用下煤颗粒周围气体的振荡流动特性[J]. 计算物理, 2017, 34(4): 425-436.

XU Weilong, JIANG Genshan, AN Liansuo, LIU Yuechao, WU Yapan. Oscillating Flow Characteristics Around Coal Particle in High Intensity Sound Field[J]. CHINESE JOURNAL OF COMPUTATIONAL PHYSICS, 2017, 34(4): 425-436.

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