基于场协同理论的热声回热器数值研究

Numerical study on thermoacoustic regenerator based on field coordination principle

热声回热器是热声热机的重要部件。基于Rayleigh准则,提出回热器内流固之间的对流换热强度是影响热声热机整体性能的重要因素。利用改进的数值模型,模拟了平行板叠内回热器的速度与温度分布特性,并分析了板叠内部对流换热及整机性能之间的对应关系。此外,基于强化对流传热的场协同理论,提出了4种新型结构的异型回热器,并分别对其换热性能与热声转换性能进行了对比分析研究:表明采用混合型回热器的热声热机具有更优越的工作性能,输出声功的压力振幅较普通结构回热器可提高2.8%。研究结果验证了热声回热器内部对流换热强度与热声热机性能呈正相关性,通过改良回热器结构可有效提高热声热机的热声转换性能。

The regenerator is an important component of thermoacoustic engine. On the basis of Rayleigh＇ s criterion, the intensity of heat convection between fluid and solid in regenerator is presumed as one of the dominant factors determining the perfonnance of thermoacoustic engine . To further clarify the relationship, a reformed numerical model was proposed and then firstly applied to predict the distribution of velocity and temperature in a thermoacoustic regenerator consisted of parallel stacks, which was a common structure of regenerators. The relationship of heat convection in regenerator and the performance of thermoacoustic engine was also analyzed. Referring to the field - coordination principle, four different structures of regenerators were separately proposed and then adopted to the engine. And a comparison was conducted between numerical results （ i. e. the situations of heat convection and and performances of thermo - acoustic transformation） of the engines adopting the different regenerators. The re- suits indicate that the mixed - type rengerator has a better performance, in which the pressure amplitude of output acoustic power increases by 2.8%, comparing to the common structure. The positive correlation between intensity of heat convection in thermoacoustic engine and performance of thermoaeoustic engine is also verified in this study. And it is feasible to improve the performanee of thermoacoustic transformation by modifying the structure of regenerator.