• Title, Summary, Keyword: 유량맥동

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Effect of Inflow Fluctuation of LOX Manifold of Liquid Rocket on the Flow (산화제 매니폴드 입구유동의 맥동 현상이 산화제 분사량에 미치는 영향)

  • Lee Gunho;Byun Yung-Hwan;Na Yang
    • Journal of the Korean Society of Propulsion Engineers
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    • v.8 no.3
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    • pp.68-74
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    • 2004
  • Effect of fluctuation imposed on the inflow to LOX manifold of liquid rocket has been analyzed numerically. Time-varying fluctuation was idealized by the sinusoidal signal and three different representative frequencies were considered. It was found that all the frequencies tested produced the consistent flow reactions in the manifold in that the place close to the region of infection showed oscillatory flow rate through injector orifices in phase with the inflow fluctuation whereas the other side exhibits characteristics which are out of phase.

Mass Flow Rate Measurement of Pulsating Flow in a Twin-Scroll Turbocharger (트윈스크롤 터보과급기에서 맥동유동의 질량유량 측정)

  • Chung, Jin-Eun;Jeon, Se-Hun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.12
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    • pp.723-729
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    • 2019
  • Turbochargers are an effective device to reduce the fuel consumption. In this study, the mass flow rate of pulsating flow in the twin-scroll turbocharger for the gasoline engine of passenger vehicles was measured. Pulsating flow was achieved using a pulse generator and the mass flow rate of the unsteady pulsating flow was analyzed by comparing it with those of the steady flow. The pulse generator consisted of a rotating upper plate and a fixed lower plate. To measure the mass flow rate of unsteady flow, the orifice flow meter equipped with the difference pressure transducer was used. To analyze the low speed performance of the turbocharger, the measurement was carried out in the speed of turbocharger from 60,000rpm to 100,000rpm. The mass flow parameters of the unsteady pulsating flow showed a large difference compared to those of the steady flow. Those of the unsteady flow showed the hysteresis loop surrounding the mass flow parameters of the steady flow and the maximum variation of the mass flow parameters were 5.0 times those of the steady flow. This phenomenon is the result of the filling and emptying the turbine volute space due to pulsating flow.

Changes in The Pressure-Flow Control Characteristics of Shunt Valves by Intracranial Pressure Pulsation (뇌압 펄스에 의한 션트밸브의 압력-유량제어 특성의 변화)

  • 홍이송;이종선;장종윤
    • Journal of Biomedical Engineering Research
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    • v.23 no.5
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    • pp.391-395
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    • 2002
  • Shunt valves used to treat patient with hydrocephalus were numerically simulated to investigate influence of pressure pulsation on their flow control characteristics. We modeled flow orifice through the shunt valve and imposed pulsating pressure and valve diaphragm movement to compute flow through the valve. The results of our study indicated that flow rates increased more than 40% by introducing pressure pulsation and diaphragm movement on the shunt valve. Our results demonstrate the pressure-flow control characteristics of shunt valves implanted above human brain may be quite different from those obtained by syringe pump test just after manufacture that induces uniform pressure.

Optimal Design of Gerotor with Combined Lobe Profiles (Ellipse 1-Elliptical Involute-Ellipse 2) (타원 1-타원형 인벌루트-타원 2 로브 형상의 제로터 최적 설계)

  • Kwak, Hyo Seo;Li, Sheng Huan;Kim, Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.12
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    • pp.1237-1244
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    • 2015
  • A gerotor can be manufactured in a miniature size because it has a high discharge per cycle and a simple structure. Gerotors are widely used for the lubrication oil of an engine and as the hydraulic source of an automatic transmission. Recently, improvements in fuel efficiency and noise reduction have come to the fore in the automobile industry, and it has been necessary for better fuel efficiency to continuously improve the flow rate and noise of internal gear pumps through the optimal design of the gerotor and port shape. In this study, gerotors were generated based on the equations derived for a lobe shape with multiple profiles (ellipse 1-elliptical involute-ellipse 2). The ranges of the design parameters were considered to prevent a cusp and loop. In addition, the optimal lobe shape was obtained by determining the influence of the lobe shape on the performances (flow rate, irregularity, etc.), according to the values of the design parameters.

Measurement of Flow Ripple Generated by Balanced Vane Pumps in Automotive Power Steering Systems (동력조향용 압력평형형 베인펌프의 유량맥동 계측)

  • Kim, Do-Tae;Kim, Jin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.6
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    • pp.70-78
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    • 2000
  • A balanced vane pump for the use of automotive power steering systems generates a flow ripple which is imposed upon the mean flow rate. The flow ripple interacts with the characteristics of the connected pipes, valves and steering gear in a complex manner to produce a pressure ripple, also known as fluid-borne noise. In order to reduce vibration level and produce quieter and more reliable power steering systems, it is important to measure the flow ripple produced by a pump with high accuracy and fast response. In this paper, the flow ripple generated by a vane pump in automotive power steering systems is measured by the remote instantaneous flow rate measurement method (RIFM) using hydraulic pipeline dynamics. In experiment, flow and pressure ripple wave forms are measured under various operating conditions. Also, the parameters affected upon the flow and pressure ripple are investigated by the frequency analysis.

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A Study on the Measurement of Delivery Flow Ripple Generated by Hydraulic Axial Piston Pumps (유압용 액셜 피스톤 펌프의 유량맥동 계측에 관한 연구)

  • 이상기
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.8 no.2
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    • pp.35-43
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    • 1999
  • The paper describes an approach for measuring delivery flow ripple generated by oil hydraulic axial piston pumps. In order to reduce pressure ripple which cause to undesirable noise. vibration and fatigue in hydraulic systems it is indispensible measure a delivery flow ripple from pumps. Since the flow ripple measurement of flow pumps is independent of the dynamic characteristics of the connected hydraulic circuit the measurement of flow ripple is most suitable for pump fluid-borne noise rating. The measurement of flow ripple with high frequencies from axial piston pumps is made by applying the remote instantaneous flow rate measurement method which is based on the dynamic characteristics between pressure and flow rate in hydraulic pipeline. The measured flow ripple waveforms are influenced by the configuration of V-shaped triangular relief groove in the valve plate. It can be seen that the appropriate relief groove in valve plate reduces the pressure and flow ripple amplitude and frequency spectrum for high harmonics.

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A Study on the Discharge Pressure Ripple Characteristics of Variable Displacement Vane Pump (가변용량형 유압 베인펌프의 토출압력맥동 특성 연구)

  • 장주섭;김경훈
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.3
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    • pp.106-114
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    • 2003
  • The pressure ripple in the delivery port is caused by flow ripple, which is induced by variation of pumping chamber volume. The other reason is the reverse flow from the outlet volume produced by pressure difference between pumping chamber and outlet volume, when the pumping chamber is connected with the outlet volume. In this study, a mathematical model is presented for analyzing discharge pressure ripple, which includes vane detachment, cam ring movement , and fluid inertia effects in V-groove in the side plate. From the analysis and experiment, it was found that V-groove on the side plate, coefficient of spring supporting the cam ring, and average discharge pressure are the main factors of discharge pressure ripple in variable displacement vane pump. The theoretical results, provided in this study, were well agreed with experimental results. The analytical model to estimate the magnitude of pressure ripple in this study is expected to be used f3r the optimal design of the variable displacement vane pump.

Flow Ripple Simulation Model of Axial Piston Pump (액시얼 피스톤 펌프의 맥동유량 시뮬레이션 모델)

  • Lee I.Y.;Park J.H.;Kang M.G.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.2 no.3
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    • pp.12-17
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    • 2005
  • This paper presents a theoretical study of the delivery flow ripple produced by a swash plate type hydraulic piston pump for the purpose of developing a computer simulation program capable of predicting the pump source flow ripple accurately at the design stage. Particular attention has been paid to the development of the theoretical model by clarifying quantitatively the design influences of key parts of valve plate such as relief groove and pre-compression/expansion.

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Measurement of Hydraulic Pump Flow Ripple Characteristics Based on the ISO 10767-1 and the Evaluation of the Measuring Accuracy (ISO 10767-1에 기초한 유압 펌프의 유량 맥동 측정 및 정밀도 평가)

  • Kim, J.W.;Kang, M.G.;Lee, I.Y.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.4 no.3
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    • pp.22-27
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    • 2007
  • The source flow ripple and the source impedance in hydraulic pump are characteristic values showing fluid-borne vibration characteristics decisively. We cannot measure these two characteristic values directly, but can measure them by some indirect methods. One representative indirect measuring method is ISO 10767-1. The authors constructed a hardware and a software for the measuring method based on ISO 10767-1. Through the error evaluation of the measured results, accuracy of the measuring method using ISO 10767-1 was examined in detail.

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