谐振管形状对热声发动机内非线性声场的影响  

Influence of resonator shape on nonlinear acoustic field in a thermoacoustic engine

作　　者：刘丹晓[1] 周城光[1] 刘克[1] 

机构地区：[1]中国科学院噪声与振动重点实验室(声学研究所),北京100190

出　　处：《声学学报》2012年第1期36-44,共9页Acta Acustica

基　　金：国家自然科学基金(10574135);中科院三期知识创新工程重要方向(KJCX2-YW-W02)资金项目

摘　　要：研究了谐振管一端受活塞声源激励,另一端刚性封闭条件下,管道形状对热声发动机谐振管内部非线性声场的影响。基于流体力学基本方程建立了渐变截面谐振管内一维非线性声场的模型,考虑了黏性耗散及非线性效应的影响。利用伽辽金法数值求解了该模型的速度势方程,分析了谐振管形状、活塞振动速度及激励频率对管内声场的影响。将双曲形、指数形、锥形、正弦形等四种变截面谐振管内的非线性声场与圆柱形直管的情况进行了比较。结果反映了谐振管内声场的压力波动受活塞振动速度及谐振管形状的影响;显示了当活塞振动幅度较大时,谐振管内出现的波形畸变、频率曲线偏移、共振频率滞后等非线性现象;揭示了变截面谐振管在抑制管内的高阶谐波及提高压比等方面的优越性。The influence of the resonator shape on nonlinear acoustic field in a thermoacoustic engine is studied. The resonator of themoaeoustic engine is boundary driving by a piston at one end, and the other end of it is rigid closed. A one-dimensional wave equation that accounts for gas dynamic nonlinearities and viscous dissipation in the resonator is established based on the governing equations of viscous hydromechanics. The nonlinear wave equation is solved using approximate Galerkin method. The nonlinear acoustic field in four different types of varying cross section resonators including hyperbolical, exponential, conical and sinusoidal are obtained and compared with that of a cylindrical resonator. It is found that the amplitude and waveform of pressure oscillations are strongly affected by the resonator shape, the driving amplitude and frequency of the piston. Waveform distortion, resonance frequency shift and hysteresis are observed, when the piston oscillation amplitude is large enough. The advantages of varying cross section resonator in thermoacoustic engine are revealed in inhibition of higher order harmonics, improvement of pressure ratio, etc.

关 键 词：非线性效应 热声发动机 谐振管 声场 形状 激励频率 振动速度 非线性现象 

分 类 号：O422.7[理学—声学]