Sound Attenuation in Tubes due to Visco-Thermal Effects
Sound Attenuation in Tubes due to Visco-Thermal Effects
复制标题
由于粘热效应引起的管内声音衰减
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
P. Hrnjak
中科院分区：
文献类型：
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作者：
E. Rodarte;G. Singh;N. Miller;P. Hrnjak
周期性轴向声波在圆柱结构气体中的传播是四个参数的函数：s=Rρ·ω/μ，剪切波数或斯托克斯数，k=ω·R/c，称为约化频率，σ=μ·Cp/λ，普朗特数的平方根和γ=Cp/Cv，比热比。1868年Tijdeman [1]用这些参数表示了管中声传播问题的完全基尔霍夫解。在以前的工作[1，2]中，通过求解该表达式来获得复传播常数。在参考文献[1]中给出了有限范围的结果，在参考文献[2]中给出了更宽范围的结果，但在这两种情况下，仅针对单一流体空气。在这项工作中，计算机代码来解决这个传播常数的结果。该代码用于在5<s<5000、0·01<k<6、0·8<σ<1·1和1·0<γ<1·7的范围内找到传播常数（衰减和相移系数）。这一范围的条件涵盖了大多数感兴趣的条件。然后，数据被用来拟合一个方程，以更简单的多项式型表达式作为这四个参数的函数来表达衰减和相移系数。还提供了一组表格，用于获得上述范围内这四个无量纲参数值的衰减和相移系数值。使用过热R134 a制冷剂的声衰减测量结果与平面波区域的计算衰减相当吻合。
The propagation of periodic axial sound waves in gases contained in circular cylindrical structures is a function of four parameters: s=Rρ·ω/μ, the shear wave number or Stokes number, k=ω·R/c, known as the reduced frequency, σ=μ·Cp/λ, the square root of the Prandtl number and γ=Cp/Cv, the ratio of specific heats. The complete Kirchhoff solution of the sound propagation in tubes problem obtained in 1868 was expressed in terms of these parameters by Tijdeman [1]. In previous works [1, 2] the complex propagation constant was obtained by solving this expression. The results were presented for a limited range in reference [1] and for a broader range in reference [2] but in both cases only for a single fluid, air. In this work the results of a computer code to solve for this propagation constant are presented. The code was used to find the propagation constants (attenuation and phase-shift coefficients) in the range 5<s<5000, 0·01<k<6, 0·8<σ<1·1 and 1·0<γ<1·7. This range of conditions covers most conditions of interest. The data was then used to fit an equation to express the attenuation and phase-shift coefficients in terms of simpler polynomial-type expressions as a function of these four parameters. A set of tables to obtain the values of the attenuation and phase shift coefficients for values of these four non-dimensional parameters in the above range is also presented. Sound attenuation measurements using superheated R134a refrigerant agrees reasonably well with the computed attenuation in the plane wave region.