平面型热声转换装置的特性分析

Characteristic analysis of planar thermoacoustic transducer

利用热声效应制作出一种由加热层、绝缘层和储热层构成的平面型热声转换装置.对加热层输入交变电压信号时,由于焦耳效应及各层材料的不同热力学特性,其表面附近区域会产生相应的声波.通过对装置模型进行理论分析,推导出装置输出声压及效率的表达关系式,并利用高速数据采集系统及红外成像仪对装置工作特性进行了实验研究.结果表明:该平面型热声转换装置的输出声压和效率随输入电功率的增大而增大;环境温度对装置输出声压的影响较小;通过对装置表面静态温度场分布进行分析,得到装置结构的优化方法.该装置实现了电能、热能、声能之间的转换,具有无任何运动部件、频率可控、稳定性高等优点,因而可广泛用于电声换能领域.

Based on the thermoacoustic effect, a type of planar therrnoacoustic transducer composed of a heating surface, an insulation layer and a thermal storage substrate is manufactured. When the alternative voltage signal is input to the heating surface, the sound wave can be obtained near the heating surface area due to the Joule heating effect and the different thermodynamic characteristics ofthe materials in each layer. Through the theoretical analysis of the transducer, the expression of the sound pressure and the efficiency are obtained. The operating characteristics of the transducer are studied by the high-speed data acquisition system and the infrared camera.The experimental resultsshow that the output sound pressure and the efficiency of the transducer are proportional to the input electric power. The influence of the ambient temperature on the output sound pressure is small. The optimization methods of the transducer＇ s structure are indicated by analyzing the distribution of thestatic temperature field of the transducer＇ s surface. The conversion of electricity, thermal energy and sound energy can be realized by the transducer. And the transducer has the advantages of no moving parts, controllable frequency, and high stability. So it can be widely used in the electro-acoustic transducer field.