• Title, Summary, Keyword: Flow Rate Irregularity

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Studies on the Draw Resonance and Filament Irregularity in Melt Spinning(I) -Effects of Spinning Conditions of Polypropylene on the Filament Irregularity- (용융방사에 있어서 연신공명과 섬유 불균제도에 관한 연구(I) -폴리프로필렌의 방사조건이 섬유 불균제도에 미치는 영향-)

  • 정호규;김상용
    • Textile Science and Engineering
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    • v.32 no.3
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    • pp.289-299
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    • 1995
  • The effects of spinning conditions on the filament irregularity and the periodicity of irregularity caused by draw resonance in the melt spinning of polypropylene were investigated. The filament irregularity increased with the increase of draw ratio at both isothermal and nonisothermal conditions, but the slope of irregularity versus draw ratio and the period al nonisothermal conditions were smaller than those at isothermal condition. In both isothermal and nonisothermal conditions, the filament irregularity increased with the flow rate, but decreased with spinning temperature. In the isothermal conditions, filament irregularity increased with the spin length, but decreased in nonisothermal condition. When the draw ratio was increased, the amplitude of the fiber diameter variation increased, but the frequency of oscillation was unchanged. This results illustrated that the draw resonance is a hydrodynamic instability The period of irregularity caused by draw resonance increased with spin length, and decreased with flow rate, but spinning temperature had no effect on the period.

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A Study on the Design of a New Rotor in Internal Pumps (내부 펌프의 새로운 로버 설계에 관한 연구)

  • Chang, Young-June;Kim, Jae-Hun;Han, Seung-Moo;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.3
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    • pp.100-107
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    • 2007
  • A 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 lobes with circular shape, while the inner rotor profile is determined as conjugate to the other. The topic of this paper is the design of a new rotor, which is based on specific performance as different types depending on the shape of the lobe of the outer rotor. First, the design of internal lobe pumps with circular, elliptical, and their combined lobe profiles is considered. The latter is a new type of lobe profile with special shape whose curvature follows a definite function. Then we introduce the performance indexes used for the comparison. Some of these indexes, such as flow rate and flow rate irregularity, are commonly used for the comparison, while specific slipping is particularly suitable in this case. It is possible to notice that the circular and elliptical type is comparable to the circular one or the elliptical one in terms of flow rate irregularity, but has improved performance in terms of specific slipping. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

Optimum design on the lobe shapes of Gerotor Oil Pump (제로터 오일 펌프 로버형상에 관한 최적설계)

  • Kim Jae-Hun;Kim Chang-Ho;Kim Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.4
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    • pp.124-131
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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 internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobes with circular shape, while the inner rotor profile is determined as 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 odor 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 far 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 oil pump to be more efficient in this field, and the system could serve as a valuable one for experts and as a dependable training aid for beginners.

Development of an Automated Design System for Oil Pumps with Ellipse Lobe Profile (타원의 치형 형상을 갖는 로터 설계 자동화 시스템 개발)

  • Jung, Sung-Yuen;Han, Seung-Moo;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.1
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    • pp.120-129
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    • 2009
  • 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 lobes with elliptical shape, while the inner rotor profile is determined as conjugate to the other. And the integrated system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

Development of an Automated Design System for Oil Pumps with Multiple Profiles(Circle, Ellipse and Involute) (원, 타원 및 인벌루트 조합된 치형형상을 갖는 로터 개발)

  • Jung, Sung-Yuen;Kim, Moon-Saeng;Cho, Hae-Yong;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.3
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    • pp.103-112
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    • 2009
  • A 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 system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

Development of a New Gerotor for Oil Pumps with Multiple Profiles(Ellipse1, Involute and Ellipse2) (타원 1-인벌루트-타원 2 형상을 조합한 새로운 형 제로터 개발)

  • Jung, Sung-Yuen;Kim, Moon-Saeng;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.5
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    • pp.614-622
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    • 2011
  • 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 multiple profile(ellipse1, involute and ellipse2) shapes, while the inner rotor profile is determined as conjugate to the other. Also, the design of outer rotor depends on new applications with removing carryover phenomenon. The system generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. In order to obtain rotor shapes in performance and to find optimize the design parameters, a Taguchi method is proposed in this paper. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

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.