| 驻波声场中圆柱形管道周围颗粒的运动特性 |
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| 引用本文： | 刘月超,姜根山,杨延锋,孔倩.驻波声场中圆柱形管道周围颗粒的运动特性[J].声学学报,2023,48(2):356-365. |
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| 作者姓名： | 刘月超 姜根山 杨延锋 孔倩 |
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| 作者单位： | 1.华北电力大学 数理系 保定 071003 |
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| 基金项目： | 国家自然科学基金项目 (12274122, 12074118)、河北省自然科学基金项目 (A2021502001, A2019502160) 和 中央高校基本科研业务费(2020 MS140)资助. |
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| 摘 要： | 针对圆柱形管道外部的流体与颗粒介质运动问题,提出了结合圆柱周围声辐射力和声流Stokes力的研究方法。从柱体外部声流方程出发,得到影响涡流结构的无量纲参数Rem≥325.27时,外涡最大流速大于内涡最大流速。在此基础上,采用Nyborg的边界滑移速度理论,获得管道外部声流的极限滑移速度,推导得出圆柱附近的声辐射力公式。基于此公式,在理论上推导出颗粒速度为0、声辐射力和声流Stokes力平衡时,颗粒临界直径的表达式。通过对圆柱位于不同位置时,圆柱外部的颗粒运动进行仿真模拟,得到与理论公式相一致的结论:颗粒的临界直径的大小与声波频率有关,当颗粒直径小于临界直径时,声流Stokes力为主导,颗粒随声流运动,颗粒直径大于等于临界直径时,声辐射力为主导,颗粒在声辐射力作用下逐渐向声辐射力的节点聚集。理论与仿真结果表明该方法可用于分析管道外颗粒的分布状态,其研究结果有助于解决电站中换热器的管道结垢、热交换率降低等问题。
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| 关 键 词： | 声流 换热器管道 驻波声场 颗粒运动 |
| 收稿时间： | 2021-12-15 |
Motion characteristics of particles around the cylindrical tube in a standing wave sound field |
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| Affiliation: | 1.Department of Mathematics and Physics, North China Electric Power University Baoding 0710032.Hebei Key Laboratory of Physics and Energy Technology, North China Electric Power University Baoding 0710033.School of Mathematics and Physics, North China Electric Power University Beijing 1022064.School of Energy Power and Mechanical Engineering, North China Electric Power University Beijing 102206 |
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| Abstract: | A calculation method combining the acoustic radiation force around the cylinder and the acoustic streaming Stokes force is proposed to calculate the motion of fluid and granular media outside a cylindrical tube. Using the acoustic streaming equation outside the cylinder, the external vortex is obtained as the main body of flow when Rem ≥ 325.27, where Rem is the dimensionless parameter that depends on the structure of the vortex. On this basis, the limit slip velocity of the acoustic streaming outside the tube is calculated by using Nyborg's boundary slip velocity theory, and the acoustic radiation force formula near the cylinder. The expression of particle critical diameter is derived when the particle velocity is zero and the acoustic radiation force and the acoustic streaming Stokes force are in equilibrium. The movement of particles outside the cylinder at different positions is simulated, and the results are consistent with the theoretical formula: the particles’ critical diameter is related to the acoustic frequency. When the particle diameter is less than the critical diameter, the Stokes force of the acoustic streaming is dominant, and the particles move with the acoustic streaming. When the particle diameter is greater than or equal to the critical diameter, the acoustic radiation force is dominant, and the particles gradually congregate at the node of the acoustic radiation force under the action of the acoustic radiation force. Theoretical and simulation results show that the proposed method can be used to examine the distribution of particles outside the tube, and the results are helpful to solve the problems of tube scaling and reduction of the heat exchange rate of heat exchangers and steam generators in power stations. |
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