• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.33-38
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• 2010

As for an oil hydraulic vane pump of vehicle hydraulic systems, the highest of planning technique required by the acquisition of optimum profile data which can be available to predict noises and vibrations. Pressure pulsation may result in considerable vibration and noise of pump component as well as cavitation in hydraulic system. The influences of the discharge pressure and rotating speed of the vane on the dynamic pressure in chamber surrounding a vane have been investigated. It is very important to predict pressure pulsation in vane pump. This paper presents analysis of technique of vane pump for automatic transmission. The predicted result using AMESim model were good agreement with the experimentally obtained results.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1310-1323
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• 2023

A reactor coolant pump (RCP) is essential for transporting coolant in the primary loop of pressurized water reactors. In the advanced passive reactor, the absence of a long pipeline between the steam generator and RCP serves as a transition section, resulting in a non-uniform flow field at the pump inlet. Therefore, the characteristics of the pump should be investigated under non-uniform flow to determine its influence on the pump. In this study, the pressure pulsation characteristics were examined in the time and frequency domains, and the sources of low-frequency and high-amplitude signals were analyzed using wavelet coherence analysis and numerical simulation. From computational fluid dynamics (CFD) results, non-uniform inflow has a great effect on the flow structures in the pump's inlet. The pressure pulsation in the pump at the rated flow increased by 78-128.7% under the non-uniform inflow condition in comparison with that observed under the uniform inflow condition. Furthermore, a low-frequency signal with a high amplitude was observed, whose energy increased significantly under non-uniform flow. The wavelet coherence and CFD analysis verified that the source of this signal was the low-frequency pulsating vortex under the steam generator.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.7
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• pp.793-798
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• 2012

Oil gear pump is used for the cooling pump system of commercial vehicle. The hydraulic pulsation pressure of oil gear pump is one of the most important reasons for the vibration and noise of the pump. In this study, the several hydraulic factors acting on oil gear motor are analyzed by CFD in operation of cooling system. Forced vibration analysis due to hydraulic pulsation pressure is analyzed by FEA for predicting deformation and equivalent stress.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.794-803
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• 2021

The instantaneous acceleration affects the performance of the water-jet pump obviously. Here, based on the user-defined function, the method to simulate the inner flow in water-jet pumps under acceleration conditions was established. The effects of two different acceleration modes (linear acceleration and exponential acceleration) and three kinds of different acceleration time (0.5s, 1s and 2s) on the performance of the water-jet pump were analyzed. The results show that the thrust and the pressure pulsation under exponential acceleration are lower than that under linear acceleration at the same time; the vapor volume fraction in the impeller under linear acceleration is 27.3% higher than that under exponential acceleration. As the acceleration time increases, the thrust gradually increases and the pressure pulsation amplitude at the impeller inlet and outlet gradually decreases, while the law of pressure pulsation is the opposite at the diffuser outlet. The main frequency of pressure pulsation at the impeller outlet is different under different acceleration time. The research results can provide some reference for the optimal design of water-jet pumps.

• International Journal of Fluid Machinery and Systems
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• v.6 no.3
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• pp.121-136
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• 2013

This paper reports the 1-D fluid transient simulation results of the discharge flow conditions in a 6-cylinder reciprocating slurry pump. Two discharge manifold configurations are studied comparatively; a case with a hexagon shaped discharge manifold where each cylinder discharges at a single vertex, and a case where all the cylinders discharges are lumped together into a tank shaped manifold. In addition, the study examines the effect of two pulsation mitigation measures in the case of hexagonal manifold; a single inline orifice in one of the hexagon sides and a volumetric dampener at the manifold outlet. The study establishes the pressure and flow fluctuation characteristics of each configuration and decouples the pulsation characteristics of the pump and the discharge manifold.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.1
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• pp.89-95
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• 2016

This study investigated the design factors of the opening area in order to consider the kinematic stability of a valve plate, conducting an analysis of the reduction effects of pressure pulsation and flow ripple depending on the design factors, using the $SimulationX^{(R)}$ (Germany) hydraulic analysis program. Further, we performed a structure analysis to confirm the kinematic stability of the valve plate in a swash plate type piston pump, and analyzed the effects of pulsation on a 1-step V-type notch, 2-step V-type notch, and 2-step U-type notch to determine the effects of pulsation reduction. Finally, we show the effectiveness of our proposed design of the pre-compression sections on a valve plate in terms of low pulsation by using the hydraulic analysis program, $SimulationX^{(R)}$.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.1
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• pp.18-23
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• 2011

With hydraulic noise test facility, a variety of tests were performed to investigate the pulsation pressure generation mechanism and its transmission characteristics and to derive the noise control methodology. Many experiments were carried out by changing average pressure, flow rate, pump speed, hose length and MCV spool condition. From the test results, the correlations between pulsation pressure and other design parameters, such as static pressure, flow rate and MCV spool opening area and length of hose, were found out. And also each contribution factors were evaluated from the regression analysis. By changing hose length, the pulsation pressure resonance phenomenon was investigated. In order to find out the pulsation pressure reduction measures pulsation pressure analysis, such as pulsation pressure of hydraulic pump itself and pulsation pressure of hydraulic system, by using AMESim were studied. In addition hydraulic silencer was developed based on the Helmholtz resonator. And its performance was evaluated by installing the silencer at the excavator.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.1
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• pp.88-95
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• 2000

In this paper, an expansion-resonator type pulsation attenuator is proposed to absorb and attenuate flow an pressure ripple with high frequencies generated from hydraulic control systems. The basic principle of a pulsation attenuator proposed here is applied to propagation, reflection, absorption of pressure waves at the cross section of discontinuity and resonance in the pipeline. It has advantage of the compact size and high degree fo freedom for installation in hydraulic systems. The design scheme based on distributed parameter pipeline system with dissipative viscous compressible model is developed. To investigate the reduction of flow and pressure ripple with high frequencies produced by swash plate type axial piston pump, two kinds of attenuators are manufactured. It is experimently confirmed that the spectral intensity of flow and pressure ripple with high frequencies from the pump are reduced up to about 20$^{\circ}$~30dB by using attenuators proposed here. The calculated results were in good agreement with the measured values. From there sults of this study, it is shown that an expansion-resonator type pulsation attenuator is effective in a wide frequency ranges to attenuate the flow and pressure ripple from hydraulic components.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1-5
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• 2007

A majority of piping vibration problems are induced by internal fluid pulsation; turbulent flow, vortex shedding at internal discontinuities, and pressure pulsation at equipment nozzles. The pulsation at the pressure sources resonates acoustically with the piping and the amplified pressure pulsation can generate shell mode vibration in the piping. Reheater attemperator piping supplies water from feedwater pump to reheater attemperator to control the boiler temperature. In normal operating condition, the high frequency shell mode vibration occurred in the piping with the high level of sound(105 ${\sim}$ 117 dB). The vibration sources are pressure pulsation in the pump nozzle and the frequencies are related to the blade passing frequencies. The objects of this paper are to analyze the cause of the high frequency vibration and to establish corrective actions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.395-400
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• 2003

Power steering oil pump is generally used to support the power to steering system of most kinds of vehicle. The noise caused by power steering ell pump make passenger to be uncomfortable, because its frequency is higher than that is produced by engine. In this paper, the field test of real car was carried out to analyze the phenomenon of the pump noise, and the lab test was also performed to survey the dynamic characteristics of pump assembly. The results of the series of tests show that frequency range of 600-800㎐ should be dealt with to reduce the pump noise. After four cases of design changes were carried out to actually reduce the noise and tested in condition of partial assembly. Some improvement can be gotten from a certain design change.