• Title, Summary, Keyword: Flow Rate Irregularity

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Development of Rotor for Internal Gear Pump using Cycloid and Polycircular-arc Curves (사이클로이드 및 폴리서클 곡선을 이용한 내접형 기어펌프용 치형 개발)

  • Kim, Min-Soo;Lee, Hyun-Woo;Jung, Sung-Yuen;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.9
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    • pp.1003-1011
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    • 2012
  • A new type of gerotor developed in this paper has the inner rotor designed by inserting a polycircular-arc between the hypocycloid and epicycloid curves, and we also suggest that the outer rotor be designed using the closed-form equation for the inner rotor and a method of modification. Thus, it is possible to design a gerotor for which there is no cusp and loop, as in this case undercut is prevented. We developed automated program for rotor design and calculation of the flow rate and flow rate irregularity. And we also demonstrate the superior performance of the gerotor developed in this study by analyzing the internal fluid flow using a commercial computation fluid dynamics-code (CFD).

Development of an Integrated System for Automated Design of Gerotor Oil Pump (지로터 오일 펌프용 통합적 설계 자동화 시스템 개발)

  • Kim, Jae-Hun;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.2
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    • pp.88-96
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    • 2006
  • A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. Especially the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of the internal lobe pump which is a particular type of positive displacement pump. The main components of the pump are rotors; usually the outer rotor profile is characterized by lobes with circular shape, while the inner rotor profile is determined as conjugate as the outer rotor profile. For this reason the topic presented here is the definition of the geometry of the rotors starting from the design parameters. The choice of these parameters is subject to some limitations in order to avoid cusp and loop between rotors. And the integrated system which is composed of three main modules has been developed through AutoLISP & Visual Basic and CAD considering various design parameters. It generates automatically an designed model for a general type of a gerotor pump and allows us to calculate two performances indexes commonly used for the study of positive displacement pumps: the flow rate and flow rate irregularity. Results obtained using the system enable the designer and manufacturer of oil pump to be more efficient in this field.

Optimum Design on Lobe Shapes of Gerotor Oil Pump

  • Kim, J.H.;Kim, Chul;Chang, Y.J.
    • Journal of Mechanical Science and Technology
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    • v.20 no.9
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    • pp.1390-1398
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    • 2006
  • A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular the pump is an essential machine element that feeds lubricant oil in an automotive engine. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the two rotors. Usually the outer one is characterized by lobes with a circular shape, while the inner rotor profile is determined as a conjugate to the other. For this reason the first topic presented here is the definition of the geometry of the rotors starting from the design parameters. The choice of these parameters is subject to some limitations in order to limit the pressure angle between the rotors. Now we will consider the design optimization. The first step is the determination of the instantaneous flow rate as a function of the design parameter. This allows us to calculate three performance indexes commonly used for the study of positive displacement pumps the flow rate irregularity, the specific flow rate, and the specific slipping. These indexes are used to optimize the design of the pump and to obtain the sets of optimum design parameter Results obtained from the analysis enable the designer and manufacturer of the oil pump to be more efficient in this field.

Design of Gerotor Using Cycloid and Circular-Arc Curves (사이클로이드 및 원호 곡선을 이용한 제로터 개발)

  • Choi, Tae-Hoon;Kim, Moon-Saeng;Lee, Geun-Su;Jung, Sung-Yuen;Kim, Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.3
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    • pp.241-250
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    • 2011
  • The new gerotor developed in this paper has an inner rotor in which a circular arc is inserted between the hypocycloid and epicycloid curves, whereas the outer rotor is designed using the simulation results for the rotor and a modification method. The new gerotor has no cusps and loops and no limit on the eccentricity. We increase the average flow rate by adding a new design parameter, $\gamma$, which is the inclined angle of the inner rotor at the intersection of the hypocycloid and the circular arc. A calculation method to calculate the chamber area is also developed. This method can also be used to calculate the flow rate and flow rate irregularity when the contact points are unknown. The control of eccentricity and $\gamma$ is expected to lead to an efficient rotor.

Characteristics of Flow past a Sphere in Uniform Shear (균일 전단유동 내에 위치한 구 주위의 유동특성)

  • Kim, Dong-Joo;Choi, Hyung-Seok;Choi, Hae-Cheon
    • Proceedings of the KSME Conference
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    • pp.1607-1612
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    • 2004
  • Numerical simulations are performed to investigate the characteristics of flow past a sphere in uniform shear. The Reynolds numbers considered are Re=300, 425 and 480 based on the inlet center velocity and sphere diameter. The non-dimensional shear rate K of the inlet uniform shear is varied from 0 to 0.15. At Re=300, the head of the hairpin vortex loop always locates on the high-velocity side in uniform shear, and the flow maintains the planar symmetry. At Re=425 and 480, the irregularity in the location and strength of the hairpin vortex appearing in uniform inlet flow is much reduced in uniform shear, but the flows still keep the asymmetry for most inlet shear rates. However, in the cases of K=0.075 and 0.1 at Re=425, the flows become planar symmetric and their characteristics of the evolution of the hairpin vortex loops are different from those of asymmetric flows. A hysteresis phenomenon switching from the planar symmetry to the asymmetry (or vice versa) depending on the initial condition is also observed at Re=425.

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Development of an Automated Integrated Design System for Gerotor Pumps with Multiple Profiles(Ellipse and Involute) (타원.인벌루트 조합 형상을 갖는 지로터 펌프의 통합적 설계 자동화 시스템 개발)

  • Moon, Hyun-Ki;Jung, Sung-Yuen;Bae, Jun-Ho;Chang, Young-June;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.9
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    • pp.67-77
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    • 2010
  • An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobe with elliptical and involute shapes, while the inner rotor profile is determined as conjugate to the other. And the integrated design system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance plus CFD-ACE+. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. CFD simulation results show trends similar to those carried out in experiments, and a quantitative comparison is presented. Results obtained from the automotive integrated design system enable the designer and manufacturer of oil pump to be more efficient in this field.

Optimal Design of Tooth Profile for High-Efficiency Gerotor Oil Pump (지로터 오일 펌프의 성능 향상을 위한 치형의 최적 설계)

  • Kim Jae Hun;Park Joon Hong;Jung Sung Yuen;Son Jin Hyuk;Kim Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.5
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    • pp.28-36
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    • 2005
  • A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications, which are highly accepted by designers. Especially the pump is an essential machine element of an automotive engine to feed lubricant oil. However, related industries do not have necessary technology to design and optimize the pump and paid royalties of rotor profile on an advanced country. Also, gerotor pumps with unsettled design parameters have not been sufficiently analyzed from a theoretical view of design. Therefore, it is still very difficult for the pump designer and manufacturer to decide the specifications for the required gerotor pump by users. In this study, the design optimization has been carried out to determine the design parameters that maximize the specific flow rate and minimize the flow rate irregularity. Theoretical analyses and optimal design of the gerotor oil pump have been performed by mathematical base, numerical method and knowledge of kinematics. An automated design system of the tooth profile has been developed through Auto LISP language and CAD method considering various design parameters. Finally, an optimally designed model for a general type of a gerotor pump has been generated and experimentally verified for the pump performances.

Design and Analysis of Gerotor with Generalized Shapes for Power-Steering Units (파워 스티어링 유닛용 일반형상 제로터의 설계 및 해석)

  • Jeong, Jae-Tack;Shin, Soo-Sik;Kim, Kap-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.7
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    • pp.891-896
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    • 2010
  • A gerotor is used in power-steering units (PSUs) as well as in hydraulic motors or pumps. The inner rotor is developed on the basis of the shape of the outer rotor tooth, which normally has one arc. The method of generating inner rotor on the basis of a generalized shape of outer rotor is analyzed with a view to improve PSU characteristics. An arc-shaped outer rotor with two curvatures was used in the analysis; design parameters such as the shape and curvature of the inner rotor, the flow rate of the gerotor, the position of contact point, and slip velocity are calculated, and these results are shown. This analysis enables us to develop a new design of compact PSUs.

Passive autocatalytic recombiner guide structure considering ambient flow (분위기 유동을 고려한 PAR 가이드 구조에 관한 연구)

  • Ryu, Myeong-Rok;Park, Kweon-Ha
    • Journal of the Korean Society of Marine Engineering
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    • v.41 no.4
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    • pp.302-309
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    • 2017
  • If a hydrogen explosion occurs in a containment building, its multiplex defense wall may be destroyed and a large amount of radioactive material may be released. The hydrogen occurred interacting with melting fuel rods must be effectively controlled and removed. however, the countermeasures for reducing explosion risk are difficult to carry out, due owing to the various variety of accident scenarios causes and the irregularity of hydrogen distribution and behavior. In this study, We examine the guide structures while considering the ambient flows, in order to improve the efficiency of PAR the widely used Passive Autocatalytic Recombiner(PAR). We simulate the fluid behavior and the hydrogen reduction rate were simulated when a guide is attached to the two-step catalyst PAR. For an upward flow, the consisting of a height of 150mm, a gap of 0mm, and a performs $60^{\circ}$ showed the best. In contrast, for a sideways flow, a consisting of the height of 150mm, a gap of 100mm, and a performs $60^{\circ}$ showed the best in the case of side ward flow. for a downward flow, a consisting of the height of 50mm and a directly attached guide produce the best in the case of down ward flow results.