可用于热声发电的曲柄连杆式换能器阻抗特性理论研究

Study on Impedance Characteristics of Crank-rod Transducer Used in Thermoacoustic Power Generation System

热声发电系统具有高效、可靠、结构简单及外燃等独特优势,在煤层气发电、太阳能发电及工业余热利用等领域应用前景广阔。本文针对用于热声发电的曲柄连杆式换能器,建立了物理模型,讨论了活塞质量、转动惯量及电路负载对换能器阻抗特性的影响,表明固定频率、振幅的压力波驱动下,由于曲柄连杆式换能器行程固定,其阻抗幅值不变,而相位角随负载电阻减小而减小,阻抗实部值相应增大。最后根据换能器阻抗特性,简化模拟了采用曲柄连杆式换能器的行波热声发电系统DeltaEC模型,模拟显示在充气压力3.16 MPa、热源温度650℃时,系统可输出约645.4 W电功(热电效率16.6%),表明此换能器用于大功率、低成本热声发电的优势。本研究为曲柄连杆式换能器与大功率热声热机高效匹配的应用提供了理论基础。

Thermoacoustic generation system （TAGS） has great advantages of high efficiency high reliability, simple structure and external combustion form, showing a promising prospect in applications such as coal bed gas power generation, solar power generation and industrial waste heat recovery, etc. In this paper, the physical model of the crank-rod transducer （CRT） used in TAGS is developed. The effects of piston weight, rotational inertia and electrical load on the acoustic impedance of CRT are then discussed, showing that given the pressure amplitude and frequency, the amplitude of impedance is steady due to the fixed stroke, while the phase angle decreases with the reduction of load resistance, making the real part of CRT impedance increase. Finally, a DelatEC Model of travelling-wave TAGS using CRT is simulated, the result shows that with charging pressure of 3.16 MPa and hot temperature of 650℃ the system can provide 645.4 W electric power with 16.6% thermo-eleetric efficiency, indicating CRT has an edge in high power and low cost TAGS. This study provides the theoretical foundation for the efficient matching between the CRT and high power TAGS.