Cavitation is a common issue in pumps,causing a decrease in pump head,a fall in volumetric efficiency,and an intensification of outlet flow pulsation.It is one of the main hazards that affect the regular operation of ...Cavitation is a common issue in pumps,causing a decrease in pump head,a fall in volumetric efficiency,and an intensification of outlet flow pulsation.It is one of the main hazards that affect the regular operation of the pump.Research on pump cavitation mainly focuses on mixed flow pumps,jet pumps,external spur gear pumps,etc.However,there are few cavitation studies on external herringbone gear pumps.In addition,pumps with different working principles significantly differ in the flow and complexity of the internal flow field.Therefore,it is urgent to study the cavitation characteristics of external herringbone gear pumps.Compared with experimentalmethods,visual research and cavitation area identification are achieved through computation fluid dynamic(CFD),and changing the boundary conditions and shape of the gear rotor is easier.The simulation yields a head error of only 0.003%under different grid numbers,and the deviation between experimental and simulation results is less than 5%.The study revealed that cavitation causes flow pulsation at the outlet,and the cavitation serious area is mainly distributed in the meshing gap and meshing area.Cavitation can be inhibited by reducing the speed,increasing the inlet pressure,and changing the helix angle can be achieved.For example,when the inlet pressure is 5 bar,the maximumgas volume fraction in themeshing area is less than 50%.These results provide a reference for optimizing the design and finding the optimal design parameters to reduce or eliminate cavitation.展开更多
This study investigated the stick-slip characteristics of a magneto-rheological elastomer (MRE) against an aluminum plate.Herein,the MRE was manufactured,and a stick-slip tester was employed to evaluate the stick-slip...This study investigated the stick-slip characteristics of a magneto-rheological elastomer (MRE) against an aluminum plate.Herein,the MRE was manufactured,and a stick-slip tester was employed to evaluate the stick-slip performance of the MRE under different velocities and load conditions with and without a magnetic field.The fast Fourier transform (FFT) of the friction force of the stick-slip and the roughness of the aluminum plate surface were calculated to confirm the stick-slip phenomenon.After the tests,the wear surfaces were observed to evaluate the wear properties of the MRE regarding the stick-slip.Results showed that the stick-slip was smaller at lower velocity.At higher velocity,the reduction of the stick-slip under a magnetic field was more clearly observed.Moreover,the wear reduced with reduced stick-slip under a magnetic field.展开更多
基金supported by a Grant(2024-MOIS35-005)of Policy-linked Technology Development Program on Natural Disaster Prevention and Mitigation funded by Ministry of Interior and Safety(MOIS,Korea).
文摘Cavitation is a common issue in pumps,causing a decrease in pump head,a fall in volumetric efficiency,and an intensification of outlet flow pulsation.It is one of the main hazards that affect the regular operation of the pump.Research on pump cavitation mainly focuses on mixed flow pumps,jet pumps,external spur gear pumps,etc.However,there are few cavitation studies on external herringbone gear pumps.In addition,pumps with different working principles significantly differ in the flow and complexity of the internal flow field.Therefore,it is urgent to study the cavitation characteristics of external herringbone gear pumps.Compared with experimentalmethods,visual research and cavitation area identification are achieved through computation fluid dynamic(CFD),and changing the boundary conditions and shape of the gear rotor is easier.The simulation yields a head error of only 0.003%under different grid numbers,and the deviation between experimental and simulation results is less than 5%.The study revealed that cavitation causes flow pulsation at the outlet,and the cavitation serious area is mainly distributed in the meshing gap and meshing area.Cavitation can be inhibited by reducing the speed,increasing the inlet pressure,and changing the helix angle can be achieved.For example,when the inlet pressure is 5 bar,the maximumgas volume fraction in themeshing area is less than 50%.These results provide a reference for optimizing the design and finding the optimal design parameters to reduce or eliminate cavitation.
文摘This study investigated the stick-slip characteristics of a magneto-rheological elastomer (MRE) against an aluminum plate.Herein,the MRE was manufactured,and a stick-slip tester was employed to evaluate the stick-slip performance of the MRE under different velocities and load conditions with and without a magnetic field.The fast Fourier transform (FFT) of the friction force of the stick-slip and the roughness of the aluminum plate surface were calculated to confirm the stick-slip phenomenon.After the tests,the wear surfaces were observed to evaluate the wear properties of the MRE regarding the stick-slip.Results showed that the stick-slip was smaller at lower velocity.At higher velocity,the reduction of the stick-slip under a magnetic field was more clearly observed.Moreover,the wear reduced with reduced stick-slip under a magnetic field.
