Flow and aeroacoustic characteristics evaluation of microjet noise reduction concept in the nozzle design for minimum quantity lubrication

Zhu, Guangyuan; Yuan, Songmei; Kong, Xiaoyao; Zhang, Chong; Chen, Bochuan

doi:10.1016/j.jsv.2020.115638

Cited by 7 publications

(4 citation statements)

References 19 publications

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“…The experimental setup is shown in Figure 4. Multiple monitoring angles (θ) and directions were selected for the OASPL experiments due to the directivities of the aerodynamic field [18]. θ is the angle between the horizontal line of the nozzle exit and the line of the nozzle and sound level meter.…”

Section: Methodsmentioning

confidence: 99%

“…The jet produced by the micro-grooved nozzle has a lower velocity and peaks at a shorter flow distance. The end of the outer mixing region is defined as the point where the nozzle has 90% of its maximum velocity [18]. The outer mixing region lengths are 6.36 D and 4.54 D for the original nozzle and the micro-groove nozzle, respectively, which indicates that the micro-grooves reduce the length of the jet mixing region.…”

Section: Analysis Of Flow Field Characteristicsmentioning

confidence: 99%

See 1 more Smart Citation

Minimum Quantity Lubrication Jet Noise: Passive Control

Hu,

Yu,

et al. 2023

Micromachines

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Jet noise is a common problem in minimum quantity lubrication (MQL) technology. This should be given great attention because of its serious impacts on the physical and mental health of the operators. In this study, a micro-grooved nozzle is proposed based on the noise reduction concept of biological micro-grooves. The flow field and acoustic characteristics of an original nozzle and a micro-grooved nozzle were investigated numerically to help better understand the noise reduction mechanism. The reasons for noise generation and the effects of the length (L), width (W) and depth (δ) of the micro-grooves on noise reduction were analyzed. It was found that jet noise is generated by the large-scale vortex ring structure and the pressure fluctuations caused by its motion. The overall sound pressure level (OASPL) decreased with the increases in W and δ, and increased with the increase in L. Among of them, δ has the greatest effect on noise reduction. The maximum noise reduction achieved was 6.66 dB, as verified by the OASPL test. Finally, the noise reduction mechanism was discussed in terms of the flow field, vorticity and the frequency characteristics. Micro-grooves can enhance the mixing of airflow inside the nozzle and accelerate the process of large-scale vortices breaking into smaller-scale vortices. It also reduces the sound pressure level (SPL) of middle frequencies, as well as the SPL of high frequencies on specific angles.

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Section: Methodsmentioning

confidence: 99%

Section: Analysis Of Flow Field Characteristicsmentioning

confidence: 99%

Minimum Quantity Lubrication Jet Noise: Passive Control

Hu,

Yu,

et al. 2023

Micromachines

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“…The author showed that the acoustic power generated by a supersonic jet is proportional to the area of the jet section multiplied by the eighth power of the velocity. Empirical and experimental approaches have been widely used because they allow for the testing of real and complex geometries and generate practical interpretations [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Customized Industrial Pneumatic Nozzle to Reduce Noise Emissions

Maffiodo,

Volpiano

2024

Applied Sciences

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This study proposes a customized industrial nozzle for generating impulsive air jets. It is installed on an automatic machine in which wine caps are stacked and shot consecutively into a rotating cylinder by an air jet. This process is very noisy; hence, this study aimed to investigate possible geometric variations of the nozzle that can reduce the emitted noise. First, the nozzle was tested in a laboratory to measure the air consumptions at different supply pressures. Subsequently, 3D models of the nozzle and its variations were created and used for computational fluid dynamics simulations. Different boundary conditions were set, first to validate the model and compare it with the experimental test results, and then to simulate the real working conditions and determine the geometry that is less noisy while maintaining the velocity peak. Among the various possibilities, shortening the final ducts of the nozzle appears to be the most promising solution. These modified nozzles could be easily added to current machines to provide immediate benefits, and this study represents a promising start for action on other machines in which this type of device is present.

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“…In terms of active noise control technology, some scholars also use microjet technology to reduce noise. The constriction effect of the microjet can significantly narrow the turbulent intensity distribution (Gza et al ,2020), and the injection of microjet can thicken the shear layer, enhance the mixing effect (Pourhashem et al , 2019) and produce a low frequency attenuation phenomenon (Castelain et al , 2006). The jet flow ratio is a key parameter, which can affect the penetration of the microjet to the core of the jet potential flow and directly affect the flow of the mainstream (Prasad and Morris, 2020).…”

Section: Introductionmentioning

confidence: 99%

Research on jet noise characteristics of aeroengine double S-bend nozzles with different cross sections

Shao

Zheng

et al. 2022

HFF

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Purpose This study aims to improve the survivability and maneuverability of the fighter,and study the stealth performance of fighter in the jet noise of aeroengine, it is of great significance to study the jet noise characteristics of double S-bend nozzles. Design/methodology/approach The multiparameter coupling and super-ellipse design methods are used to design the cross section of double S-bend nozzle. Taking unsteady flow information as the equivalent sound source, the noise signal at the far-field monitoring points were calculated with Ffowcs Williams–Hawkings (FW–H) method, and then, the sound source characteristics of the double S-bend nozzle are analyzed. Findings The results show that the internal flow of the S-bend nozzle with rectangular section is smoothed and the aerodynamic performance is better than super-ellipse section, the shear layer length of rectangular section is longer, the thickness is smaller and the mixing ability is stronger. The sound pressure level of the two S-bend nozzles decreases with the increase of the monitoring angle, and the sound pressure on the horizontal plane is greater than the vertical plane. In the direction of 40°–120°, the jet noise of rectangular nozzle is smaller, and the multiparameter coupled rectangular cross section structure is more applicable. Practical implications It is beneficial to reduce the jet noise of the engine tail nozzle and improve the stealth performance of the aircraft. Originality/value There is very little research on the jet noise characteristics of the double S-bend nozzle. The multiparameter coupling and the super-ellipse method are used to design the nozzle flow section to study the aerodynamic performance and jet noise characteristics of the double S-bend nozzle and to improve the acoustic stealth characteristics of the aircraft.

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Flow and aeroacoustic characteristics evaluation of microjet noise reduction concept in the nozzle design for minimum quantity lubrication

Cited by 7 publications

References 19 publications

Minimum Quantity Lubrication Jet Noise: Passive Control

Minimum Quantity Lubrication Jet Noise: Passive Control

Optimization of Customized Industrial Pneumatic Nozzle to Reduce Noise Emissions

Research on jet noise characteristics of aeroengine double S-bend nozzles with different cross sections

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