The pressure pulsation of axial piston pump is not only an important cause of rotation speed fluctuation,vibration noise and output stability of the hydraulic system,but also the main information source for obtaining ...The pressure pulsation of axial piston pump is not only an important cause of rotation speed fluctuation,vibration noise and output stability of the hydraulic system,but also the main information source for obtaining fault information.Hydraulic system is characterized by strong noise interference,which leads to low signal-to-noise ratio(SNR)of detection signals.Therefore,it is necessary to dig deep into the system operating state information carried by pressure signals.Firstly,based on flow loss mechanism of the plunger pump,the mapping relationship between flow pulsation and pressure pulsation is analyzed.After that,the pressure signal is filtered and reconstructed based on standard Gabor transform.Finally,according to the time-domain waveform morphology of pressure signal,four characteristic indicators are proposed to analyze the characteristics of pressure fluctuations under different working conditions.The experimental results show that the standard Gabor transform can accurately extract high-order harmonics and phase frequencies of the signal.The reconstructed time-domain waveform of pressure pulsation of the axial piston pump contains a wealth of operating status information,and the characteristics of pulsation changes under various working conditions can provide a new theoretical basis and a method support for fault diagnosis and health assessment of hydraulic pumps,motors and key components.展开更多
The optimization of the valve plate transition region is an important way of reducing the noise emission for an axial piston pump. However, the optimized methods through simulation or experiment are actually trial and...The optimization of the valve plate transition region is an important way of reducing the noise emission for an axial piston pump. However, the optimized methods through simulation or experiment are actually trial and error, and they cannot indicate the precise structural parameters of the valve plate transition region. In this study, a new design method for the transition region of valve plate based on the matching of flow area and reduction of transient reverse flow was proposed, and with which a valve plate was designed. Then, the impact of the flow ripple in the discharge line of an axial piston pump and the pressure overshoot and undershoot in the piston chamber on hydraulic and structural noise for axial piston pump is discussed. The noise reduction effect of the axial piston pump with this valve plate was analyzed by adopting a flow characteristic simulation model. Finally, the results showed that the application of this design method could contribute much to the reduction of the flow ripple and elimination of the pressure overshoot and undershoot. As a consequence, the method can be used in the design of a low-noise open circuit axial piston pump.展开更多
In this paper the inducer of the advanced-researched pump is studied. During multi-rotation speed experimentwith the medium of water, the dynamic pressures near inducer casing are obtained by transducer at each measur...In this paper the inducer of the advanced-researched pump is studied. During multi-rotation speed experimentwith the medium of water, the dynamic pressures near inducer casing are obtained by transducer at each measuringpoint mounted on the casing along the axial direction, both in the steady rotation speed period and the up anddown period. Bases on analyses, the regularity of the axial distribution of time averaged pressure and pressurepulsation amplitude, the connection between pressure pulsation frequency and rotation speeds, and the relationshipbetween the pressure pulsation amplitude and the site of inducer blade are obtained.展开更多
The study of pulsatile blood flow through axisymmetric stenosed artery subject to an axial translation has been attempted with hematocrit concentration-dependent blood viscosity. The heart contraction and subsequent r...The study of pulsatile blood flow through axisymmetric stenosed artery subject to an axial translation has been attempted with hematocrit concentration-dependent blood viscosity. The heart contraction and subsequent relaxation generate periodic pressure gradient in blood flow and translation in the artery can be represented by Fourier series. Numerical data required for computing Fourier harmonics for the pressure gradient and acceleration in the artery has been simulated from pressure waveform graph and biplanar angiogram. Velocity field has been obtained by solving governing equation using variational Ritz method. The hemodynamic indicators WSS, AWSS, OSI, RRT are derived and computed numerically. The effects of thickness of stenosis, and hematocrit concentration index on these indicators are computed and analyzed through graphs.展开更多
基金National Natural Science Foundation of China(No.51675399)。
文摘The pressure pulsation of axial piston pump is not only an important cause of rotation speed fluctuation,vibration noise and output stability of the hydraulic system,but also the main information source for obtaining fault information.Hydraulic system is characterized by strong noise interference,which leads to low signal-to-noise ratio(SNR)of detection signals.Therefore,it is necessary to dig deep into the system operating state information carried by pressure signals.Firstly,based on flow loss mechanism of the plunger pump,the mapping relationship between flow pulsation and pressure pulsation is analyzed.After that,the pressure signal is filtered and reconstructed based on standard Gabor transform.Finally,according to the time-domain waveform morphology of pressure signal,four characteristic indicators are proposed to analyze the characteristics of pressure fluctuations under different working conditions.The experimental results show that the standard Gabor transform can accurately extract high-order harmonics and phase frequencies of the signal.The reconstructed time-domain waveform of pressure pulsation of the axial piston pump contains a wealth of operating status information,and the characteristics of pulsation changes under various working conditions can provide a new theoretical basis and a method support for fault diagnosis and health assessment of hydraulic pumps,motors and key components.
基金the National Basic Research Program (973 Program) of China，the Science Fund for Creative Research Groups of the National Natural Science Foundation of China
文摘The optimization of the valve plate transition region is an important way of reducing the noise emission for an axial piston pump. However, the optimized methods through simulation or experiment are actually trial and error, and they cannot indicate the precise structural parameters of the valve plate transition region. In this study, a new design method for the transition region of valve plate based on the matching of flow area and reduction of transient reverse flow was proposed, and with which a valve plate was designed. Then, the impact of the flow ripple in the discharge line of an axial piston pump and the pressure overshoot and undershoot in the piston chamber on hydraulic and structural noise for axial piston pump is discussed. The noise reduction effect of the axial piston pump with this valve plate was analyzed by adopting a flow characteristic simulation model. Finally, the results showed that the application of this design method could contribute much to the reduction of the flow ripple and elimination of the pressure overshoot and undershoot. As a consequence, the method can be used in the design of a low-noise open circuit axial piston pump.
文摘In this paper the inducer of the advanced-researched pump is studied. During multi-rotation speed experimentwith the medium of water, the dynamic pressures near inducer casing are obtained by transducer at each measuringpoint mounted on the casing along the axial direction, both in the steady rotation speed period and the up anddown period. Bases on analyses, the regularity of the axial distribution of time averaged pressure and pressurepulsation amplitude, the connection between pressure pulsation frequency and rotation speeds, and the relationshipbetween the pressure pulsation amplitude and the site of inducer blade are obtained.
文摘The study of pulsatile blood flow through axisymmetric stenosed artery subject to an axial translation has been attempted with hematocrit concentration-dependent blood viscosity. The heart contraction and subsequent relaxation generate periodic pressure gradient in blood flow and translation in the artery can be represented by Fourier series. Numerical data required for computing Fourier harmonics for the pressure gradient and acceleration in the artery has been simulated from pressure waveform graph and biplanar angiogram. Velocity field has been obtained by solving governing equation using variational Ritz method. The hemodynamic indicators WSS, AWSS, OSI, RRT are derived and computed numerically. The effects of thickness of stenosis, and hematocrit concentration index on these indicators are computed and analyzed through graphs.
