Tao Zhang, Mengxue Hu, Yanzhang Geng, Tong An, Zhongzheng Liu, Xin Zhao
Transmission loss is a very important acoustic characteristic of the muffler. In order to improve the efficiency of the double-load method for measuring the transmission loss of the muffler, this paper proposes a single-step measurement method for transmission loss of muffler. In addition, the simulation model of the single-step measurement method is established based on the finite element acoustic analysis. For the model, the calculation method of the transmission loss of the muffler is deduced from the theoretical knowledge of the transfer matrix. In the simulation, the sound pressure data of six positions in the model are obtained, and the transfer matrix is used to calculate the transmission loss of the muffler. Then, two simulation comparison experiments were done. In order to verify the validity of the single-step measurement method, the first comparison experiment was to compare the transmission loss of the muffler simulated by the single-step measurement method with their theoretical transmission loss in the finite element acoustic analysis. The results of the simulation validation test cases showed that the transmission loss of the muffler obtained by the single-step measurement method was consistent with the theoretical value. The second comparison experiment was to compare the transmission loss obtained by the single-step measurement method with the transmission loss obtained by the double-load method. The results of the simulation validation test cases showed that at certain frequencies, the transmission loss obtained by the single-step measurement method was more accurate than the transmission loss obtained by the double-load method. In conclusion, the single-step measurement method proposed in this paper can accurately obtain the transmission loss of the muffler with only one measurement, which improves the measurement efficiency.
{"title":"A single-step measurement method for transmission loss of the muffler based on improved transfer matrix","authors":"Tao Zhang, Mengxue Hu, Yanzhang Geng, Tong An, Zhongzheng Liu, Xin Zhao","doi":"10.3397/1/37711","DOIUrl":"https://doi.org/10.3397/1/37711","url":null,"abstract":"Transmission loss is a very important acoustic characteristic of the muffler. In order to improve the efficiency of the double-load method for measuring the transmission loss of the muffler, this paper proposes a single-step measurement method for transmission loss of muffler. In addition,\u0000 the simulation model of the single-step measurement method is established based on the finite element acoustic analysis. For the model, the calculation method of the transmission loss of the muffler is deduced from the theoretical knowledge of the transfer matrix. In the simulation, the sound\u0000 pressure data of six positions in the model are obtained, and the transfer matrix is used to calculate the transmission loss of the muffler. Then, two simulation comparison experiments were done. In order to verify the validity of the single-step measurement method, the first comparison experiment\u0000 was to compare the transmission loss of the muffler simulated by the single-step measurement method with their theoretical transmission loss in the finite element acoustic analysis. The results of the simulation validation test cases showed that the transmission loss of the muffler obtained\u0000 by the single-step measurement method was consistent with the theoretical value. The second comparison experiment was to compare the transmission loss obtained by the single-step measurement method with the transmission loss obtained by the double-load method. The results of the simulation\u0000 validation test cases showed that at certain frequencies, the transmission loss obtained by the single-step measurement method was more accurate than the transmission loss obtained by the double-load method. In conclusion, the single-step measurement method proposed in this paper can accurately\u0000 obtain the transmission loss of the muffler with only one measurement, which improves the measurement efficiency.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46868698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The sound intensity scaling method can be used to calculate the source sound power from the array beamforming results. The distance between the sound source and the array and the environmental noise during the test process will affect the accuracy of the sound source intensity measurement. A sound power level solution method for sound intensity scaling suitable for complex environments is verified in this paper. The depth of the sound source is determined by dual arrays. The sound wave propagation and superposition characteristics are used to establish an optimized objective function, to optimize the strength of the target sound source and remove the noise components. Finally, the sound power level of the sound sources after noise reductions are calculated by the sound intensity scaling method. In the semi-anechoic room, white noise signal and impact signal are used as interference noise in the experiments. The results show that this method can effectively reduce the noise of the signal in the noisy environment and improve the calculation accuracy of the sound power level of the sound source. The error of the sound power level calculation results under the influence of white noise and impact noise has been greatly reduced after optimization. The calculation error of sound power level decreased from 3.2 dB–12.2 dB to 0.2 dB–5dB.
声强标度法可以从阵列波束形成结果中计算出源声功率。声源与阵列之间的距离以及测试过程中的环境噪声都会影响声源强度测量的精度。验证了一种适用于复杂环境的声强标度的声功率级求解方法。声源的深度由双阵列确定。利用声波的传播和叠加特性建立优化的目标函数，优化目标声源的强度，去除噪声成分。最后，采用声强标度法计算降噪后声源的声功率级。在半消声室内，实验采用白噪声信号和冲击信号作为干扰噪声。结果表明，该方法能有效降低噪声环境下信号的噪声，提高声源声功率级的计算精度。优化后的声功率级计算结果在白噪声和冲击噪声影响下的误差大大降低。声功率级的计算误差由3.2 dB ~ 12.2 dB减小到0.2 dB ~ 5db。
{"title":"Sound power estimation method based on dual arrays sound intensity scaling and sound pressure superposition","authors":"B. Jiang, Xiao-qin Liu, Xing Wu","doi":"10.3397/1/37713","DOIUrl":"https://doi.org/10.3397/1/37713","url":null,"abstract":"The sound intensity scaling method can be used to calculate the source sound power from the array beamforming results. The distance between the sound source and the array and the environmental noise during the test process will affect the accuracy of the sound source intensity measurement.\u0000 A sound power level solution method for sound intensity scaling suitable for complex environments is verified in this paper. The depth of the sound source is determined by dual arrays. The sound wave propagation and superposition characteristics are used to establish an optimized objective\u0000 function, to optimize the strength of the target sound source and remove the noise components. Finally, the sound power level of the sound sources after noise reductions are calculated by the sound intensity scaling method. In the semi-anechoic room, white noise signal and impact signal are\u0000 used as interference noise in the experiments. The results show that this method can effectively reduce the noise of the signal in the noisy environment and improve the calculation accuracy of the sound power level of the sound source. The error of the sound power level calculation results\u0000 under the influence of white noise and impact noise has been greatly reduced after optimization. The calculation error of sound power level decreased from 3.2 dB–12.2 dB to 0.2 dB–5dB.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48528411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guoxing Huang, Xianhuai Cao, Haozheng Wei, Pin Chen, Zhi-yuan Li
Power capacitors of high-voltage alternating/direct current transmission systems have become one of the main community noise sources because of their large number and because they employ ultrahigh voltage and power. According to the broadband noise characteristics of power capacitors and based on the theory of combined microperforated panels, a low-noise capacitor with broadband sound absorption is designed and machined. Noise comparison tests were conducted between the modified and conventional capacitors in a semi-anechoic chamber. The results indicate that the proposed low-noise capacitor with combined microperforated panels provides a good alternative for low-noise design of power capacitors.
{"title":"Case study: A type of low-noise power capacitor based on combined microperforated panels","authors":"Guoxing Huang, Xianhuai Cao, Haozheng Wei, Pin Chen, Zhi-yuan Li","doi":"10.3397/1/377045","DOIUrl":"https://doi.org/10.3397/1/377045","url":null,"abstract":"Power capacitors of high-voltage alternating/direct current transmission systems have become one of the main community noise sources because of their large number and because they employ ultrahigh voltage and power. According to the broadband noise characteristics of power capacitors\u0000 and based on the theory of combined microperforated panels, a low-noise capacitor with broadband sound absorption is designed and machined. Noise comparison tests were conducted between the modified and conventional capacitors in a semi-anechoic chamber. The results indicate that the proposed\u0000 low-noise capacitor with combined microperforated panels provides a good alternative for low-noise design of power capacitors.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42097843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zilong Peng, Linjiang Han, Xirui Peng, Yipeng Cheng, D. Ding
The overall acoustic echo of a submarine is greatly dependent on the conning tower. For enhancing the acoustic stealth performance of a submarine, it is necessary to research an innovative design scheme of the conning tower to reduce its bistatic target strength (TS). The aim of this work is to reduce the bistatic TS of a conning tower by varying its geometry and streamlining. The accuracy in modeling the acoustic scattering of a conning tower using the Kirchhoff approximation (KA) was validated, compared with finite element analysis. Several angular conning tower geometries were designed to analyze the effect of streamlining and the number of lateral facets on TS using the KA method. In consideration of the actual situation, the acoustic effect of backing medium was analyzed by comparing water-filled elastic hulls with rigid hulls. From the observed TS calculation results, it is shown that the non-streamlined four lateral-facet conning tower geometries are optimal for acoustic stealth performance during the range of receiving angles from -30 degrees to 30 degrees. Furthermore, elastic hulls and rigid hulls provide similar spatial distribution regularities in bistatic configuration with the rigidity affecting the magnitude of the TS.
{"title":"Research and modeling of the bistatic acoustic scattering characteristics of novel multi-faceted conning tower","authors":"Zilong Peng, Linjiang Han, Xirui Peng, Yipeng Cheng, D. Ding","doi":"10.3397/1/377044","DOIUrl":"https://doi.org/10.3397/1/377044","url":null,"abstract":"The overall acoustic echo of a submarine is greatly dependent on the conning tower. For enhancing the acoustic stealth performance of a submarine, it is necessary to research an innovative design scheme of the conning tower to reduce its bistatic target strength (TS). The aim of this\u0000 work is to reduce the bistatic TS of a conning tower by varying its geometry and streamlining. The accuracy in modeling the acoustic scattering of a conning tower using the Kirchhoff approximation (KA) was validated, compared with finite element analysis. Several angular conning tower geometries\u0000 were designed to analyze the effect of streamlining and the number of lateral facets on TS using the KA method. In consideration of the actual situation, the acoustic effect of backing medium was analyzed by comparing water-filled elastic hulls with rigid hulls. From the observed TS calculation\u0000 results, it is shown that the non-streamlined four lateral-facet conning tower geometries are optimal for acoustic stealth performance during the range of receiving angles from -30 degrees to 30 degrees. Furthermore, elastic hulls and rigid hulls provide similar spatial distribution regularities\u0000 in bistatic configuration with the rigidity affecting the magnitude of the TS.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46749108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Axial piston pump is complex fluid machinery with mechanical fluid coupling, and it has the characteristics of multiple noise sources. In order to solve the high noise problem of axial piston pump, this paper proposes a noise reduction method by identifying the main noise sources of axial piston pump and laying new damping materials to reduce noise. It breaks through the existing method of optimizing the parameters of piston pump shell and valve plate structure. A multi-parameter trajectory sensitivity identification and noise reduction method for vibration transmission path of axial piston pump is proposed in this paper. First, the lumped parameter method is used to establish the mathematical model of vibration transmission path of axial piston pump. The sensitivity of structural vibration response to transmission path multi-parameters are analyzed based on trajectory sensitivity method. The most sensitive parameters in the main noise transmission path are determined. Then, the experimental study of radiated noise transmission path of axial piston pump is carried out. A new type of viscous damping material is proposed to reduce the noise on the transmission path of the main noise source. The experimental results show that the noise of piston pump is reduced by 2.32 dB. The research results provide a new method and way for the design and manufacture of low noise piston pump.
{"title":"Study on noise reduction method of main noise transmission path of axial piston pump with new damping material","authors":"Yang Pan, Rui Liu, X. He","doi":"10.3397/1/377042","DOIUrl":"https://doi.org/10.3397/1/377042","url":null,"abstract":"Axial piston pump is complex fluid machinery with mechanical fluid coupling, and it has the characteristics of multiple noise sources. In order to solve the high noise problem of axial piston pump, this paper proposes a noise reduction method by identifying the main noise sources of\u0000 axial piston pump and laying new damping materials to reduce noise. It breaks through the existing method of optimizing the parameters of piston pump shell and valve plate structure. A multi-parameter trajectory sensitivity identification and noise reduction method for vibration transmission\u0000 path of axial piston pump is proposed in this paper. First, the lumped parameter method is used to establish the mathematical model of vibration transmission path of axial piston pump. The sensitivity of structural vibration response to transmission path multi-parameters are analyzed based\u0000 on trajectory sensitivity method. The most sensitive parameters in the main noise transmission path are determined. Then, the experimental study of radiated noise transmission path of axial piston pump is carried out. A new type of viscous damping material is proposed to reduce the noise on\u0000 the transmission path of the main noise source. The experimental results show that the noise of piston pump is reduced by 2.32 dB. The research results provide a new method and way for the design and manufacture of low noise piston pump.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45823961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aaron J. Miller, S. Sommerfeldt, Jonathan D. Blotter, D. Copley
A hybrid method for creating a unified broadband acoustic response from separate low-frequency and high-frequency simulation responses is proposed. This hybrid method is ideal for creating simple auralizable approximations of complex acoustic systems. The process consists of four steps: 1) creating separate low- frequency and high-frequency responses of the system of interest, 2) interpolating between the two responses to get a single broadband magnitude response, 3) introducing amplitude modulation to the high-frequency portion of the response, and 4) calculating approximate phase information. Once the appropriate frequency response is obtained, an inverse fast Fourier transform is applied to obtain an impulse response. An experimental setup of an acoustic cavity with one flexible wall is used to validate the hybrid method. The simulated and measured impulse responses are both convolved with various excitation signals, so the validity of the approach could be assessed by listening. Listening tests confirm that the method is able to produce realistic auralizations. The degree of realism is subject to a few limitations, such as pitch differences and dependence on the presence of transients in the excitation signal, but these limitations are incidental and only indirectly related to the proposed method.
{"title":"A hybrid method for creating auralizations of vibroacoustic systems","authors":"Aaron J. Miller, S. Sommerfeldt, Jonathan D. Blotter, D. Copley","doi":"10.3397/1/377048","DOIUrl":"https://doi.org/10.3397/1/377048","url":null,"abstract":"A hybrid method for creating a unified broadband acoustic response from separate low-frequency and high-frequency simulation responses is proposed. This hybrid method is ideal for creating simple auralizable approximations of complex acoustic systems. The process consists of four steps:\u0000 1) creating separate low- frequency and high-frequency responses of the system of interest, 2) interpolating between the two responses to get a single broadband magnitude response, 3) introducing amplitude modulation to the high-frequency portion of the response, and 4) calculating approximate\u0000 phase information. Once the appropriate frequency response is obtained, an inverse fast Fourier transform is applied to obtain an impulse response. An experimental setup of an acoustic cavity with one flexible wall is used to validate the hybrid method. The simulated and measured impulse responses\u0000 are both convolved with various excitation signals, so the validity of the approach could be assessed by listening. Listening tests confirm that the method is able to produce realistic auralizations. The degree of realism is subject to a few limitations, such as pitch differences and dependence\u0000 on the presence of transients in the excitation signal, but these limitations are incidental and only indirectly related to the proposed method.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48154964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Previous studies of rotating detonation engines (RDEs) focused on combustion, heat transfer, and propulsion, but not noise, which is considered here. High-frequency pressure sensors, such as dynamic sensors, are often used as contact measurements to determine the detonation pressure and rotating detonation cycle time, but they obtain data for only a few seconds. Here, a simple and inexpensive acoustic measurement method is used to obtain the high-frequency sound pressure of the detonation and cycle time over more than a few hours and is not affected by high-temperature products. The results show that data of non-contact acoustic measurements, which can reflect the rotating detonation characteristics, agree well with those of picocoulomb pressure sensors and high-speed imaging. The production mechanism of sharp noise caused by rotating detonation waves is analyzed theoretically and compared with experimental results. Kinematic equations for vibrations are derived, and disturbance trajectories caused by oblique shock waves are found to be Archimedes spirals. This constitutes the first study on noise from RDEs. The study also promotes acoustic measurements, which have rarely been used to study RDEs.
{"title":"Experimental study of sharp noise caused by rotating detonation waves","authors":"Yuhui Wang, J. Le","doi":"10.3397/1/377046","DOIUrl":"https://doi.org/10.3397/1/377046","url":null,"abstract":"Previous studies of rotating detonation engines (RDEs) focused on combustion, heat transfer, and propulsion, but not noise, which is considered here. High-frequency pressure sensors, such as dynamic sensors, are often used as contact measurements to determine the detonation pressure\u0000 and rotating detonation cycle time, but they obtain data for only a few seconds. Here, a simple and inexpensive acoustic measurement method is used to obtain the high-frequency sound pressure of the detonation and cycle time over more than a few hours and is not affected by high-temperature\u0000 products. The results show that data of non-contact acoustic measurements, which can reflect the rotating detonation characteristics, agree well with those of picocoulomb pressure sensors and high-speed imaging. The production mechanism of sharp noise caused by rotating detonation waves is\u0000 analyzed theoretically and compared with experimental results. Kinematic equations for vibrations are derived, and disturbance trajectories caused by oblique shock waves are found to be Archimedes spirals. This constitutes the first study on noise from RDEs. The study also promotes acoustic\u0000 measurements, which have rarely been used to study RDEs.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44844675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xingzhong Nong, Xinwei Luo, Q. Feng, Hao Zhou, Qinming Tu
In this paper, a noise test on the viaduct of a city in China was conducted to analyze the effect of trapezoidal sleepers, sound barriers, and the combination of trapezoidal sleepers and sound barriers on the spatial distribution characteristics of overall noise. A statistical energy analysis model was established to analyze the influence of these sound barrier configurations. The results show that at the speed of 60 km/h, the trapezoidal sleeper track can reduce the overall noise by 2.0 dB to 6.0 dB. The upright-type sound barrier can reduce the overall noise by 10.3 dB to 13.2 dB, with the most significant frequency band of noise reduction above 800 Hz; the combination of the trapezoidal sleeper and sound barrier has a significant noise reduction effect above 31.5 Hz, and the overall noise reduction can reach 13.8 dB to 23.1 dB. The high-frequency wheel-rail noise decays faster with distance, while the low-frequency bridge structure noise decays slowly with distance. When sound barriers are set up on both sides of the viaduct, the sound pressure level at the near field point is further reduced by 3.3 dB to 5.2 dB compared with sound barriers on only one side. Compared with a section with no sound barriers, the noise inside the sound barriers is about 1.2 dB higher than when the sound barriers are set on one side or both sides of the viaduct.
{"title":"Analysis of the effect of combined noise reduction measures of trapezoidal sleeper and sound barrier on elevated line","authors":"Xingzhong Nong, Xinwei Luo, Q. Feng, Hao Zhou, Qinming Tu","doi":"10.3397/1/377049","DOIUrl":"https://doi.org/10.3397/1/377049","url":null,"abstract":"In this paper, a noise test on the viaduct of a city in China was conducted to analyze the effect of trapezoidal sleepers, sound barriers, and the combination of trapezoidal sleepers and sound barriers on the spatial distribution characteristics of overall noise. A statistical energy\u0000 analysis model was established to analyze the influence of these sound barrier configurations. The results show that at the speed of 60 km/h, the trapezoidal sleeper track can reduce the overall noise by 2.0 dB to 6.0 dB. The upright-type sound barrier can reduce the overall noise by 10.3\u0000 dB to 13.2 dB, with the most significant frequency band of noise reduction above 800 Hz; the combination of the trapezoidal sleeper and sound barrier has a significant noise reduction effect above 31.5 Hz, and the overall noise reduction can reach 13.8 dB to 23.1 dB. The high-frequency wheel-rail\u0000 noise decays faster with distance, while the low-frequency bridge structure noise decays slowly with distance. When sound barriers are set up on both sides of the viaduct, the sound pressure level at the near field point is further reduced by 3.3 dB to 5.2 dB compared with sound barriers on\u0000 only one side. Compared with a section with no sound barriers, the noise inside the sound barriers is about 1.2 dB higher than when the sound barriers are set on one side or both sides of the viaduct.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47386165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cavitation has become a serious concern threatening operational stability as the need for high-speed machinery has grown. In this study, noise (sound pressure level) and vibrations (structural) were measured in a radial flow centrifugal pump for design and off-design conditions under cavitation. Because the structure of a particular noise/vibration spectrum (as well as its total level) is affected by the operating conditions and stage of cavitation within the pump, a detailed analysis the noise/vibration spectra during the pumping process was carried out to detect of the cavitation phenomenon's progression. We aim to identify the association between noise/vibration and the corresponding net positive suction head value at different flow rates. The results showed that the cavitation structure affects the vibration/noise behavior of the pump. Moreover, total noise level measurements at partial flow rates cannot be used to diagnose full cavitation breakdown, whereas total noise level measurements can be used to detect cavitation intensity at higher flow rates than the optimum operating point.
{"title":"Experimental investigation of cavitation-induced noise and vibration in a centrifugal pump","authors":"M. Kaya, H. Erol","doi":"10.3397/1/377043","DOIUrl":"https://doi.org/10.3397/1/377043","url":null,"abstract":"Cavitation has become a serious concern threatening operational stability as the need for high-speed machinery has grown. In this study, noise (sound pressure level) and vibrations (structural) were measured in a radial flow centrifugal pump for design and off-design conditions under\u0000 cavitation. Because the structure of a particular noise/vibration spectrum (as well as its total level) is affected by the operating conditions and stage of cavitation within the pump, a detailed analysis the noise/vibration spectra during the pumping process was carried out to detect of the\u0000 cavitation phenomenon's progression. We aim to identify the association between noise/vibration and the corresponding net positive suction head value at different flow rates. The results showed that the cavitation structure affects the vibration/noise behavior of the pump. Moreover, total\u0000 noise level measurements at partial flow rates cannot be used to diagnose full cavitation breakdown, whereas total noise level measurements can be used to detect cavitation intensity at higher flow rates than the optimum operating point.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42490831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Low-pressure fans are widely used in industrial machinery as well as in home-use electrical apparatus. Consequently, their improved aerodynamic performance and reduced fan noise are important technical issues. This study developed a methodology for the experimental determination of the pressure power spectral density (PSD) of a flat plate based on a wind tunnel experiment and the broadband noise generated from a low-pressure fan predicted based on its pressure PSD. In the proposed methodology, the broadband noise of the fan was evaluated by superimposing the predicted broadband noise of the divided blade elements in the impeller. Using this methodology, the broadband noise of the objective fan could be predicted via the wind tunnel experiment and the representative internal flow properties of the fan such as relative velocity and deviation angle. Moreover, the relationship between the broadband noise in the design and off-design conditions and the flow regime were analyzed by referring to the parameters for the prediction. In the off-design low flow rate condition, the flow around the impeller became a swirling flow owing to the increasing back pressure, and the fan noise in the off-design condition increased, especially in the low-frequency domain. The broadband noise was generated by leakage flow in the vicinity of the leading edge at the blade tip which interfered with the adjacent blade. Therefore, the mechanism of broadband noise generation in the off-design condition distinguished the mechanism of trailing edge noise. As indicated by the results of the predicted broadband noise comparison, the suggested experimental methodology best represented the measured noise spectra in the design condition. The experimental pressure PSD showed that the broadband noise in the design condition was affected by the trailing edge noise generated at the blade tip.
{"title":"Prediction of broadband noise generated from low-pressure fan based on experimental pressure power spectral density","authors":"Soichi Sasaki","doi":"10.3397/1/377047","DOIUrl":"https://doi.org/10.3397/1/377047","url":null,"abstract":"Low-pressure fans are widely used in industrial machinery as well as in home-use electrical apparatus. Consequently, their improved aerodynamic performance and reduced fan noise are important technical issues. This study developed a methodology for the experimental determination of\u0000 the pressure power spectral density (PSD) of a flat plate based on a wind tunnel experiment and the broadband noise generated from a low-pressure fan predicted based on its pressure PSD. In the proposed methodology, the broadband noise of the fan was evaluated by superimposing the predicted\u0000 broadband noise of the divided blade elements in the impeller. Using this methodology, the broadband noise of the objective fan could be predicted via the wind tunnel experiment and the representative internal flow properties of the fan such as relative velocity and deviation angle. Moreover,\u0000 the relationship between the broadband noise in the design and off-design conditions and the flow regime were analyzed by referring to the parameters for the prediction. In the off-design low flow rate condition, the flow around the impeller became a swirling flow owing to the increasing back\u0000 pressure, and the fan noise in the off-design condition increased, especially in the low-frequency domain. The broadband noise was generated by leakage flow in the vicinity of the leading edge at the blade tip which interfered with the adjacent blade. Therefore, the mechanism of broadband\u0000 noise generation in the off-design condition distinguished the mechanism of trailing edge noise. As indicated by the results of the predicted broadband noise comparison, the suggested experimental methodology best represented the measured noise spectra in the design condition. The experimental\u0000 pressure PSD showed that the broadband noise in the design condition was affected by the trailing edge noise generated at the blade tip.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42992895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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