摘要
为探究声波作用下铜球的对流换热机理,搭建了声波强化传热实验台架,研究在不同声压级和声频率的影响下铜球的对流换热问题,并结合声流的作用机理和实验数据深入分析了声波强化传热机理。结果表明:铜球的对流传热系数和努塞尔数随着声压级的增大而非线性增大,且存在强化传热的最佳声频率;相对努塞尔数主要受声频率和声压级的综合影响,而与铜球直径的关系不大;对于给定声压级,声波强化铜球的传热过程随频率的不同可大致划分为4个阶段,即声流控制区、声流和振荡流协同控制区、振荡流控制区和稳定区,并给出前3个阶段相对努塞尔数的经验公式。
To explore the mechanism of convective heat transfer of copper sphere under the action of sound wave, an experimental bench was set up to study the effect of sound waves with different sound pressure levels and sound frequencies on the convective heat transfer of the copper sphere. Combined with the action mechanism of sound flow and experimental data, the mechanism of heat transfer enhancement by sound wave was analyzed in depth. Results show that the convective heat transfer coefficient and Nusselt number of copper sphere increase nonlinearly with the increase of sound pressure level, and there exists an optimal sound frequency, when the enhancement of heat transfer is maximized. The relative Nusselt number is affected comprehensively by sound frequency and sound pressure level, which is slightly related to the diameter of copper sphere. For a given sound pressure level, the heat transfer process of sound wave enhanced copper sphere can be roughly divided into four stages: acoustic streaming control region, acoustic streaming and oscillatory flow cooperative control region, oscillatory flow control region and stable region. Finally, the empirical formula of relative Nusselt number in the first three stages is presented.
作者
杨延锋
姜根山
许伟龙
姜羽
YANG Yanfeng;JIANG Genshan;XU Weilong;JIANG Yu(School of Energy,Power and Mechanical Engineering,North China Electric Power University,Beijing 102206,China;School of Mathematics and Physics,North China Electric Power University,Beijing 102206,China)
出处
《动力工程学报》
CAS
CSCD
北大核心
2021年第2期136-143,共8页
Journal of Chinese Society of Power Engineering
基金
国家自然科学基金资助项目(11474091,11674093,12074118)
河北省自然基金资助项目(A2019502160)
声场声信息国家重点实验室资助项目(SKLA201808)。
关键词
声波
传热
声流
振荡流
努塞尔数
sound wave
heat transfer
acoustic streaming
oscillatory flow
Nusselt number
