Numerical analysis of the transmission loss of water muffler according to the two-load method

Gong, Junbo; Jiang, Zhiyuan; Xuan, Liang; Ying, Baosheng; Peng, Weicai

doi:10.1177/0954406220919464

Cited by 2 publications

(1 citation statement)

References 11 publications

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“…Transmission loss measurements are typically carried out using the two-microphone method by the two-source method or the two-load method [21][22][23][24]. In principle transmission losses of a damper depend on the acoustic properties of the system on the transmission-side (as opposed to the source-side of the system).…”

Section: Introductionmentioning

confidence: 99%

Analytical modelling and experimental validation of compliance-based low-frequency resonators for water circuits

Kottapalli¹,

Meerendonk²,

Waterson³

et al. 2022

Acta Acust.

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Transmission losses of compact compliance-based resonators in water circuits are investigated. Experiments are performed to measure the anechoic transmission losses (TLan) of flexible-plate resonators and a gas resonator designed for frequencies between 10 and 100 Hz. The measurements are compared to theoretical results based on a lumped-element model and a finite-element model. The TLan is measured using a robust form of the multi-microphone method, which gave identical results for open and closed pipe acoustic terminations at the transmission side of the setup. When an estimate of the reflection coefficient at the termination is known, good results are obtained with only one transmission-side microphone. When TLan is high, a single microphone is sufficient on each side. For the flexible-plate resonators the TLan measurements are in agreement with theory except close to resonance, where the transmission signals are below the detection limit. Due to assumptions of a rigid cavity wall and a clamped top-plate, the theoretical resonance frequencies are too high except for the thinnest plate which displays static deformation stiffening. This deformation stiffening limits the possibility to lower the resonance frequency by using a thin flexible plate in a circuit with high static pressure. Low resonance frequencies are easier to reach with a gas resonator, in which a piston separates the water from a volume filled with air. For the gas-resonator, the measurements agree with the theoretical predictions when assuming a significant damping. The friction between the air-water-separation piston and cavity wall is suspected to cause this damping. Theory predicts that the TLan of both resonators designed for same resonance frequencies in absence of losses are equivalent. They therefore have quite similar performances except close to the resonance frequency. The flexible-plate resonator has a higher quality factor and higher (TLan) around the resonance frequency. The gas resonator is more complex and needs more maintenance but allows fine tuning of the resonance frequency by varying the gas volume.

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Section: Introductionmentioning

confidence: 99%

Analytical modelling and experimental validation of compliance-based low-frequency resonators for water circuits

Kottapalli¹,

Meerendonk²,

Waterson³

et al. 2022

Acta Acust.

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Research on the wave transmission characteristics of a flexible chamber inserted in the fluid-filled elastic pipeline

Hu,

Liu,

Zhao

et al. 2024

Journal of Vibration and Control

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In the acoustic calculations of pneumatic pipeline systems, it is commonly assumed that the walls of the pipeline are rigid. It leads to the development of various acoustic theories based on rigid wall. However, in situations involving high-density fluids or thin-walled structures, the propagation of waves in the pipeline becomes complex due to the strong vibroacoustic coupling. In such cases, the wave transmission characteristics calculation methods based on the rigid wall assumption are no longer applicable. This paper employs the pipeline waveguide theory to estimate the wave transmission characteristics in the presence of complex wave behavior within the pipeline. Once the accuracy of the proposed method has been verified, the wave responses of a flexible chamber inserted in the fluid-filled elastic pipeline are analyzed. The analysis shows that the lowest-order fluid-type waves and the lowest-order longitudinal extension waves are found to propagate in the pipeline. The incident lowest-order fluid-type wave and its transmitted wave of the same mode can be successfully separated from other waves. The elasticity of the pipe wall can significantly affect the acoustic characteristics of an expansion chamber. Nevertheless, significant disparities in the wave amplitudes and limited sampling pose challenges to accurate calculations of the transmission loss.

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Numerical analysis of the transmission loss of water muffler according to the two-load method

Cited by 2 publications

References 11 publications

Analytical modelling and experimental validation of compliance-based low-frequency resonators for water circuits

Analytical modelling and experimental validation of compliance-based low-frequency resonators for water circuits

Research on the wave transmission characteristics of a flexible chamber inserted in the fluid-filled elastic pipeline

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