考虑基底热传导的石墨烯薄膜热声理论
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摘要
主要基于热声效应对石墨烯薄膜发声进行理论研究。首先建立了石墨烯薄膜耦合热振动模型,推导出了石墨烯薄膜发声器的声压表达式。在此基础上,进行了不同基底石墨烯薄膜发声器的声压测试,并将测试值与理论计算结果对比,二者随频率变化趋势基本吻合,测试值略低于理论值,验证了推导出的声压表达式的正确性。研究表明石墨烯薄膜发声器有很宽的频域响应,在低频段声压级随频率增大而增大,在高频段响应平稳,具有作为优秀的热致发声器的潜力。基底材料蓄热系数越小,石墨烯薄膜的声压值越大;声压级随薄膜热容量的增大而减小。研究结果对于石墨烯的发声机制探索及其在扬声器设计等方面的应用具有指导意义。
Based on the thermo-acoustic theory, a coupled thermal-mechanical model for graphene films is established,and accurate analytical solutions for thermal-acoustic radiation from a graphene thin film is obtained. The sound pressure of the graphene film generator based on different substrates is measured, and the measured values are compared with the theoretical results, the tendency with frequency of experimental results is consistent with the theoretical values,the measured values are slightly lower than the theoretical values. Accuracy of theoretical model is verified. Studies have shown that thermal-acoustic radiation from a graphene thin film has a very wide frequency response. In the low frequency sound pressure level increases with the frequency, the acoustic pressure varies smoothly with frequency In high frequency. Thus it can be used as excellent thermal generator. The thermal effusivity of the substrate is smaller, the sound pressure of grapheme films will be higher. Furthermore, the sound pressure decreases with the increase of heat capacity per unit area of grapheme films. Results will contribute to mechanism research of graphene films generator and its application in the design of loudspeaker and other areas.
Based on the thermo-acoustic theory, a coupled thermal-mechanical model for graphene films is established,and accurate analytical solutions for thermal-acoustic radiation from a graphene thin film is obtained. The sound pressure of the graphene film generator based on different substrates is measured, and the measured values are compared with the theoretical results, the tendency with frequency of experimental results is consistent with the theoretical values,the measured values are slightly lower than the theoretical values. Accuracy of theoretical model is verified. Studies have shown that thermal-acoustic radiation from a graphene thin film has a very wide frequency response. In the low frequency sound pressure level increases with the frequency, the acoustic pressure varies smoothly with frequency In high frequency. Thus it can be used as excellent thermal generator. The thermal effusivity of the substrate is smaller, the sound pressure of grapheme films will be higher. Furthermore, the sound pressure decreases with the increase of heat capacity per unit area of grapheme films. Results will contribute to mechanism research of graphene films generator and its application in the design of loudspeaker and other areas.
引文
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2 Balandin A A,Ghosh S,Bao W et al.Superior thermal conductivity of single-layer graphene.Nano Letters,2008;8(3):902-907
3 Xiao L,Chen Z,Feng C et al.Flexible,stretchable,trans-parent carbon nanotube thin film loudspeakers.Nano Letters,2008;8(12):4539-4545
4 Tian H,Ren T L,Xie D et al.Graphene-on-paper sound source devices.ACS Nano,2011;5(6):4878-4885
5 Suk J W,Kirk K,Hao Y et al.Thermoacoustic sound generation from monolayer graphene for transparent and flexible sound sources.Advanced Materials,2012;24(47):6342-6347
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8 Kim C S,Lee K E,Lee J M et al.Application of Ndoped three-dimensional reduced graphene oxide aerogel to thin film loudspeaker.Acs Applied Materials&Interfaces,2016;8(34):22295-22300
9 Fei W,Zhou J,Guo W.Graphene foams:Low-voltage driven graphene foam thermoacoustic speaker.Small,2015;11(19):2344-2344
10籍顺心.小型热声制冷机的优化.声学学报,2007;32(2):189-191
11金滔,范理,王本仁等.PZT驱动热声制冷的性能分析.压电与声光,2003;25(3):259-262
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13 Vesterinen V,Niskanen A O,Hassel J et al.Fundamental efficiency of nanothermophones:modeling and experiments.Nano Letters,2010;10(12):5020-5024
14 Hu H,Zhu T,Xu J.Model for thermoacoustic emission from solids.Applied Physics Letters,2010;96(21):214101-214103
15周春玉,曾亮,吉莉等.石墨烯及其复合材料导热性能的研究现状.材料开发与应用,2010;25(6):94-100
16 Lim C W,Tong L H,Li Y C.Theory of suspended carbon nanotube thinfilm as a thermal-acoustic source.Journal of Sound and Vibration,2013;332(21):5451-5461
17王严冬.多孔硅热致超声发射的建模研究.合肥:中国科学技术大学,2015
18 McDonald F A,Wetsel Jr G C.Generalized theory of the photoacoustic effect.Journal of Applied Physics,1978;49(4):2313-2322
19卡姆克,鸿林.常微分方程手册.北京:科学出版社,1978
20 Xiao L,Liu P,Liu L et al.High frequency response of carbon nanotube thin film speaker in gases.Journal of Applied Physics,2011;110(8):084311-084315
2 Balandin A A,Ghosh S,Bao W et al.Superior thermal conductivity of single-layer graphene.Nano Letters,2008;8(3):902-907
3 Xiao L,Chen Z,Feng C et al.Flexible,stretchable,trans-parent carbon nanotube thin film loudspeakers.Nano Letters,2008;8(12):4539-4545
4 Tian H,Ren T L,Xie D et al.Graphene-on-paper sound source devices.ACS Nano,2011;5(6):4878-4885
5 Suk J W,Kirk K,Hao Y et al.Thermoacoustic sound generation from monolayer graphene for transparent and flexible sound sources.Advanced Materials,2012;24(47):6342-6347
6 Tian H,Yang Y,Li C et al.A flexible,transparent and ultrathin single-layer graphene earphone.Rsc.Advances,2015;5(22):17366-17371
7 Kim C S,Hong S K,Lee J et al.Free-standing graphene thermophone on a polymer-mesh substrate.Small,2016;12(2):185-189
8 Kim C S,Lee K E,Lee J M et al.Application of Ndoped three-dimensional reduced graphene oxide aerogel to thin film loudspeaker.Acs Applied Materials&Interfaces,2016;8(34):22295-22300
9 Fei W,Zhou J,Guo W.Graphene foams:Low-voltage driven graphene foam thermoacoustic speaker.Small,2015;11(19):2344-2344
10籍顺心.小型热声制冷机的优化.声学学报,2007;32(2):189-191
11金滔,范理,王本仁等.PZT驱动热声制冷的性能分析.压电与声光,2003;25(3):259-262
12马大猷.热声学的基本理论和非线性,I热声学.声学学报,1999;24(4):337-350
13 Vesterinen V,Niskanen A O,Hassel J et al.Fundamental efficiency of nanothermophones:modeling and experiments.Nano Letters,2010;10(12):5020-5024
14 Hu H,Zhu T,Xu J.Model for thermoacoustic emission from solids.Applied Physics Letters,2010;96(21):214101-214103
15周春玉,曾亮,吉莉等.石墨烯及其复合材料导热性能的研究现状.材料开发与应用,2010;25(6):94-100
16 Lim C W,Tong L H,Li Y C.Theory of suspended carbon nanotube thinfilm as a thermal-acoustic source.Journal of Sound and Vibration,2013;332(21):5451-5461
17王严冬.多孔硅热致超声发射的建模研究.合肥:中国科学技术大学,2015
18 McDonald F A,Wetsel Jr G C.Generalized theory of the photoacoustic effect.Journal of Applied Physics,1978;49(4):2313-2322
19卡姆克,鸿林.常微分方程手册.北京:科学出版社,1978
20 Xiao L,Liu P,Liu L et al.High frequency response of carbon nanotube thin film speaker in gases.Journal of Applied Physics,2011;110(8):084311-084315