In order to study the relationship between the important parameters of internal flow and the effect of drag and noise reduction,the internal flow field and sound field characteristics of bionic centrifugal pump are st...In order to study the relationship between the important parameters of internal flow and the effect of drag and noise reduction,the internal flow field and sound field characteristics of bionic centrifugal pump are studied in this paper.Based on the methods of theoretical analysis,numerical simulation and test,the relationship between wall average shear stress,drag reduction rate,increasing efficiency and noise reduction rate of internal sound field is studied.Internal flow parameters to judge and predict the effect of drag and noise reduction are revealed.The results show that the bionic pit can effectively increase the thickness of the boundary layer and reduce the Reynolds stress on the wall.The resistance on the wall is reduced and the hydraulic efficiency of the centrifugal pump is increased.The noise reduction rate is basically consistent with the changing trend of the drag reduction rate,increasing efficiency and wall average shear stress in the flow field.Wall average shear stress can reveal the effect of drag and noise reduction,so the effect of drag and noise reduction can be predicted and judged by the change of wall average shear stress.展开更多
The natural flow cooling strategy is commonly employed in modern high-speed vessels and nuclear-powered submarines. These vessels rely on the energy generated by their own speed to drive the cooling system and supply ...The natural flow cooling strategy is commonly employed in modern high-speed vessels and nuclear-powered submarines. These vessels rely on the energy generated by their own speed to drive the cooling system and supply cooling water to the condenser. The circulating pump, which operates without a motor drive under natural flow conditions, is a large resistance component in the cooling system. However, it is also the primary noise source, significantly impacting the vessel’s safe operation and acoustic stealth performance. This study investigates the induced noise characteristics of a multi-stage pump under natural flow conditions by experiment, computational fluid dynamics (CFD), and acoustic finite element method. The analysis encompasses the distribution of the flow field, variations in acoustic power, spectral features of flow-induced noise, and directivity of external field radiation noise under different natural flow conditions. The results show that the acoustic power distribution is correlated with the flow field. When the impeller is stuck, the noise sources primarily concentrate in the flow separation area at the blade’s leading edge, the interface area between the impeller and the guide vane, and the flow shock area inside the guide vane. Conversely, when the impeller rotates passively, the blade wake area has a higher acoustic power. The flow noise spectrum under natural flow conditions mainly exhibits broadband and discrete characteristics. Additionally, the pump structure influences the external field radiation noise, and its directivity varies with different flow rates and characteristic frequencies. This study provides valuable insights into optimal design to reduce the noise of the circulating pump in the vessel’s natural flow cooling system. It is essential for ensuring the safe operation and acoustic stealth performance of high-speed vessels and nuclear-powered submarines.展开更多
基金This work was supported by National Natural Science Foundation of China(Nos.51879122,51579117 and 51779106)National Key Research and Development Program of China(Nos.2016YFB0200901 and 2017YFC0804107)+4 种基金Zhenjiang key research and development plan(Nos.GY2017001and GY2018025)the Open Research Subject of Key Labo-ratory of Fluid and Power Machinery,Ministry of Education,Xihua University(Nos.szjj2017-094 and szijj2016-068)Sichuan Provincial Key Lab of Process Equipment and Control(Nos.GK201614 and GK201816)Jiangsu University Young Talent training Program-Outstanding Young backbone Teacher,Program Development of Jiangsu Higher Education Institutions(PAPD)Jiangsu top six talent summitproject(GDZB-017).
文摘In order to study the relationship between the important parameters of internal flow and the effect of drag and noise reduction,the internal flow field and sound field characteristics of bionic centrifugal pump are studied in this paper.Based on the methods of theoretical analysis,numerical simulation and test,the relationship between wall average shear stress,drag reduction rate,increasing efficiency and noise reduction rate of internal sound field is studied.Internal flow parameters to judge and predict the effect of drag and noise reduction are revealed.The results show that the bionic pit can effectively increase the thickness of the boundary layer and reduce the Reynolds stress on the wall.The resistance on the wall is reduced and the hydraulic efficiency of the centrifugal pump is increased.The noise reduction rate is basically consistent with the changing trend of the drag reduction rate,increasing efficiency and wall average shear stress in the flow field.Wall average shear stress can reveal the effect of drag and noise reduction,so the effect of drag and noise reduction can be predicted and judged by the change of wall average shear stress.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52279087,51879122).
文摘The natural flow cooling strategy is commonly employed in modern high-speed vessels and nuclear-powered submarines. These vessels rely on the energy generated by their own speed to drive the cooling system and supply cooling water to the condenser. The circulating pump, which operates without a motor drive under natural flow conditions, is a large resistance component in the cooling system. However, it is also the primary noise source, significantly impacting the vessel’s safe operation and acoustic stealth performance. This study investigates the induced noise characteristics of a multi-stage pump under natural flow conditions by experiment, computational fluid dynamics (CFD), and acoustic finite element method. The analysis encompasses the distribution of the flow field, variations in acoustic power, spectral features of flow-induced noise, and directivity of external field radiation noise under different natural flow conditions. The results show that the acoustic power distribution is correlated with the flow field. When the impeller is stuck, the noise sources primarily concentrate in the flow separation area at the blade’s leading edge, the interface area between the impeller and the guide vane, and the flow shock area inside the guide vane. Conversely, when the impeller rotates passively, the blade wake area has a higher acoustic power. The flow noise spectrum under natural flow conditions mainly exhibits broadband and discrete characteristics. Additionally, the pump structure influences the external field radiation noise, and its directivity varies with different flow rates and characteristic frequencies. This study provides valuable insights into optimal design to reduce the noise of the circulating pump in the vessel’s natural flow cooling system. It is essential for ensuring the safe operation and acoustic stealth performance of high-speed vessels and nuclear-powered submarines.
