Effects of baffle designs on damping acoustic oscillations in a solid rocket motor

Le, H. Q.; Li, Junwei; Zhao, Dan; Gu, Xingpeng; Ma, Baoyin; Wang, Ningfei

doi:10.1016/j.ast.2021.106827

Cited by 17 publications

(1 citation statement)

References 42 publications

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“…Figure 3 depicts the comparison of the present results and the previous 2D/3D numerical and experimental ones, 3 as the grazing flow Ma is set to 0, 0.03, and 0.07. 46,47 Good agreements are observed, since the maximum TL and the corresponding resonant frequency are closed to the previous experimental and numerical results. Note that the maximum TL is obtained by setting the frequency incremental step of 2 Hz.…”

Section: Description Of the Structure-modified Helmholtz Resonator An...supporting

confidence: 77%

Numerical optimizing noise damping performances of Helmholtz resonators with a rigid baffle implemented at neck in presence of a grazing flow

Guan

2022

Journal of Low Frequency Noise, Vibration and Active Control

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As an applicable noise attenuator, Helmholtz resonator is mainly used to dampen acoustic noise at low- and medium-frequency ranges. It is typically implemented in combustion-engines and gas turbines to dampen thermoacoustic instabilities. However, it has a narrow effective frequency range and does not work effectively at off-design conditions. In this work, we consider a modified structured Helmholtz resonator (HR) at its neck by applying a rigid baffle in order to maximize its’ noise damping effect and to broaden its frequency bands. The resonator is attached to a cylindrical duct/pipe in presence of a mean flow (grazing flow), aiming to simulate the practical engines flow configuration. For this, a two-dimensional frequency domain numerical model is developed by using COMSOL V5.3. The numerical simulations are carried out by solving the linearized Navier–Stokes equation in frequency domain with low computational cost and time. In order to obtain an optimum design in terms of the maximum noise damping performances, 10 new different configurations/designs are proposed. The effects of 1) the single baffle attached to the upstream or downstream sidewall of the neck ends, that is, Design A, B, C, and D or double baffles, that is, Design E, F, G, and H), 2) the baffle implementation location, 3) the length of the rigid baffle, and 4) the grazing flow low Mach number are evaluated and compared. It is found that Design C is associated with improved TL by 50% and decreased resonant frequency by 20% comparing with the conventional HR. The present preliminary study shows that Design C is the better design. Further experimental and optimization researches are needed to sheds light on the optimum design of a Helmholtz resonator with neck structure being modified, as there is a low Mach number grazing flow.

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Section: Description Of the Structure-modified Helmholtz Resonator An...supporting

confidence: 77%

Numerical optimizing noise damping performances of Helmholtz resonators with a rigid baffle implemented at neck in presence of a grazing flow

Guan

2022

Journal of Low Frequency Noise, Vibration and Active Control

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A novel method for the identification of flame front’s position on thermoacoustic coupling combustion oscillations

Gao

Peng

Huang

et al. 2021

Energy Science & Engineering

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The flame front area is an important parameter to quantify the heat release rate. However, the limitations imposed by the measuring instruments and the measurement methodologies make it difficult to determine the flame front position in an image. This work introduces a method to detect and optimize the flame front boundary. A high‐speed camera was employed to continuously capture the flame images. By setting appropriate intensity thresholds, the impact noise can be eliminated from the image and the flame front boundary can be determined. The binary diagram of the image was morphologically processed to obtain the normalized area fluctuations of the flame front in a temporally resolved manner. Two flame types and combustion regimes were studied. A LABVIEW‐based program was used for the synchronous triggering of the camera, the photomultiplier, and the microphones. The normalized area and photomultiplier output signals of a multiple flame burner obtained within the same period were compared and combined with the spectrum information from the microphone in the cavity. The trend charts were investigated in terms of the Pearson correlation coefficient. The results showed a strong correlation, thereby verifying the feasibility of this method.

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Mitigation of Combustion Instability and NOx Emissions by Microjets in Lean Premixed Flames with Different Swirl Numbers

Zhou

2023

J. Therm. Sci.

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Effects of baffle designs on damping acoustic oscillations in a solid rocket motor

Cited by 17 publications

References 42 publications

Numerical optimizing noise damping performances of Helmholtz resonators with a rigid baffle implemented at neck in presence of a grazing flow

Numerical optimizing noise damping performances of Helmholtz resonators with a rigid baffle implemented at neck in presence of a grazing flow

A novel method for the identification of flame front’s position on thermoacoustic coupling combustion oscillations

Mitigation of Combustion Instability and NOx Emissions by Microjets in Lean Premixed Flames with Different Swirl Numbers

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