Fundamental efficiency of nanothermophones: Modeling and experiments

Visa Vesterinen (Corresponding Author), Antti O. Niskanen, Juha Hassel, Panu Helistö

    Research output: Contribution to journalArticleScientificpeer-review

    76 Citations (Scopus)

    Abstract

    Scaling down the dimensions of thermoacoustic sound sources (thermophones) improves efficiency by means of reducing speaker heat capacity. Recent experiments with nanoscale thermophones have revealed properties which are not fully understood theoretically. We develop a Green’s function formalism which quantitatively explains some observed discrepancies, e.g., the effect of a heat-absorbing substrate in the proximity of the sound source. We also find a generic ultimate limit for thermophone efficiency. We verify the theory with experiments and finite difference method simulations which deal with thermoacoustically operated suspended arrays of nanowires. The efficiency of our devices is measured to be 1 order of magnitude below the ultimate bound. At low frequencies this mainly results from the presence of a substrate. At high frequencies, on the other hand, the efficiency is limited by the heat capacity of the nanowires. Measured sound pressure level and efficiency are in good agreement with simulations. We discuss the feasibility of reaching the ultimate limit in practice.
    Original languageEnglish
    Pages (from-to)5020-5024
    Number of pages5
    JournalNano Letters
    Volume10
    Issue number12
    DOIs
    Publication statusPublished - 2010
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Acoustic waves
    Experiments
    Nanowires
    Specific heat
    nanowires
    specific heat
    Thermoacoustics
    acoustics
    Substrates
    sound pressure
    Green's function
    Finite difference method
    proximity
    Green's functions
    simulation
    formalism
    low frequencies
    scaling
    heat
    Hot Temperature

    Keywords

    • Thermoacoustic
    • sound generation
    • suspended metal wire
    • frequency response
    • acoustic efficiency
    • ultrasound

    Cite this

    Vesterinen, Visa ; Niskanen, Antti O. ; Hassel, Juha ; Helistö, Panu. / Fundamental efficiency of nanothermophones : Modeling and experiments. In: Nano Letters. 2010 ; Vol. 10, No. 12. pp. 5020-5024.
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    title = "Fundamental efficiency of nanothermophones: Modeling and experiments",
    abstract = "Scaling down the dimensions of thermoacoustic sound sources (thermophones) improves efficiency by means of reducing speaker heat capacity. Recent experiments with nanoscale thermophones have revealed properties which are not fully understood theoretically. We develop a Green’s function formalism which quantitatively explains some observed discrepancies, e.g., the effect of a heat-absorbing substrate in the proximity of the sound source. We also find a generic ultimate limit for thermophone efficiency. We verify the theory with experiments and finite difference method simulations which deal with thermoacoustically operated suspended arrays of nanowires. The efficiency of our devices is measured to be 1 order of magnitude below the ultimate bound. At low frequencies this mainly results from the presence of a substrate. At high frequencies, on the other hand, the efficiency is limited by the heat capacity of the nanowires. Measured sound pressure level and efficiency are in good agreement with simulations. We discuss the feasibility of reaching the ultimate limit in practice.",
    keywords = "Thermoacoustic, sound generation, suspended metal wire, frequency response, acoustic efficiency, ultrasound",
    author = "Visa Vesterinen and Niskanen, {Antti O.} and Juha Hassel and Panu Helist{\"o}",
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    Fundamental efficiency of nanothermophones : Modeling and experiments. / Vesterinen, Visa (Corresponding Author); Niskanen, Antti O.; Hassel, Juha; Helistö, Panu.

    In: Nano Letters, Vol. 10, No. 12, 2010, p. 5020-5024.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Fundamental efficiency of nanothermophones

    T2 - Modeling and experiments

    AU - Vesterinen, Visa

    AU - Niskanen, Antti O.

    AU - Hassel, Juha

    AU - Helistö, Panu

    N1 - Project code: 30356

    PY - 2010

    Y1 - 2010

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    AB - Scaling down the dimensions of thermoacoustic sound sources (thermophones) improves efficiency by means of reducing speaker heat capacity. Recent experiments with nanoscale thermophones have revealed properties which are not fully understood theoretically. We develop a Green’s function formalism which quantitatively explains some observed discrepancies, e.g., the effect of a heat-absorbing substrate in the proximity of the sound source. We also find a generic ultimate limit for thermophone efficiency. We verify the theory with experiments and finite difference method simulations which deal with thermoacoustically operated suspended arrays of nanowires. The efficiency of our devices is measured to be 1 order of magnitude below the ultimate bound. At low frequencies this mainly results from the presence of a substrate. At high frequencies, on the other hand, the efficiency is limited by the heat capacity of the nanowires. Measured sound pressure level and efficiency are in good agreement with simulations. We discuss the feasibility of reaching the ultimate limit in practice.

    KW - Thermoacoustic

    KW - sound generation

    KW - suspended metal wire

    KW - frequency response

    KW - acoustic efficiency

    KW - ultrasound

    U2 - 10.1021/nl1031869

    DO - 10.1021/nl1031869

    M3 - Article

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    SP - 5020

    EP - 5024

    JO - Nano Letters

    JF - Nano Letters

    SN - 1530-6984

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