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- 주제어 : viscosity Index Improvers (검색결과 6 건)
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기유와 첨가제 혼합 전 다등급 윤활유의 성능 예측 시뮬레이션 프로그램 개발
전상명(Sang Myung Chun) 한국트라이볼로지학회 2012 한국윤활학회지(윤활학회지) Vol.28 No.2
Generally, to product multi-grade oil like engine oil, a sort of mineral base oil is mixed with a fundamental additive package liquid and a polymer liquid as viscosity index improver in order to improve the lubricating property of base oil. That is, engine oil is the mixture of more than two fluids. Specially, a polymeric type liquid cannot be seen as the linear viscosity like Newtonian fluids. In this research, by using the governing equation describing non-Newtonian hydrodynamic lubrication related with the mixture of incompressible fluids based on the principle of continuum mechanics, it will be compared the bearing performance between the mixture of each liquid to be blended and multi-grade engine oil as a single fluid in a high speed hydrodynamic journal bearing. Further, it is to be found the way estimating the performance of the blended multi-grade engine lubricant in a journal bearing in advance before blending by using the physical properties of mineral base oil, fundamental additive liquid and polymer liquid of viscosity index improver. So, it can be reduced the number of trial and error to get the wanted lubricant by selecting the proper volume fraction of each liquid to satisfy the expected performance and estimating in advance the performance of various multi-grade oils before blending. Therefore, it can be shorten the developing time and saved the developing cost.
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Jang, Siyonl The Korean Society of Rheology 2003 Korea-Australia rheology journal Vol.15 No.3
Elastohydrodynamic lubrication (EHL) film is measured under the condition of viscosity index improver added to base oil. In-situ optical contact method using the interference principle make the measuring resolution of ~5 nm possible and enables the measuring range all over the contact area of up to ~300 $\mu\textrm{m}$ diameter. What is more important to the developed method by the author is that the measurement of EHL film thickness is possible in the range from 100 nm to 2 $\mu\textrm{m}$, which is the regime of worst contact failures in precision machinery. Viscosity index improver (VII) is one of the major additives to the modem multigrade lubricants for the viscosity stability against temperature rise. However, it causes shear thinning effects which make the film thickness lessened very delicately at high shear rate (over $10^5 s^{-1}$) of general EHL contact regime. In order to exactly verify the VIIs performance of viscosity stability at such high shear rate, it is necessary to make the measurement of EHL film thickness down to ~100 nm with fine resolution for the preliminary study of viscosity control. In this work, EHL film thickness of VII added lubricant is measured with the resolution of ~5 nm, which will give very informative design tool for the synthesis of lubricants regarding the matter of load carrying capacity at high shear rate condition.
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Shear Thinning Effects by VII Added Lubricant with In-Situ Optical Viscometer
장시열(Siyoul Jang) 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.37 No.-
Viscosity index improver (VII) is one of the major additives to the modern multigrade lubricants for the viscosity stability against temperature rise. However, it causes shear thinning effects which make the film thickness lessened very delicately at high shear rate (over 10? s?¹) of general EHL contact regime. In order to exactly verify the VII's performance of viscosity stability at such high shear rate, it is necessary to make the measurement of EHL film thickness down to ~100㎚ with fine resolution for the preliminary study of viscosity control. In this work, EHL film thickness of VII added lubricant is measured with the resolution of ~5㎚, which will give very informative design tool for the synthesis of lubricants regarding the matter of load carrying capacity at high shear rate condition.
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고속 열유체 저어널 베어링에서 단일유체로서의 다등급 엔진 오일과 그 첨가액체들의 혼합물에 대한 성능 비교
전상명(Sang Myung Chun) 한국트라이볼로지학회 2012 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.28 No.2
To product multi-grade oil like engine oil, a sort of mineral base oil is mixed with a fundamental additive liquid package and a polymer liquid as viscosity index improver in order to improve the lubricating property of oil. That is, engine oil is the mixture of more than two fluids. In this paper, it will be systematically organized the governing equation describing non-Newtonian thermo-hydrodynamic lubrication related with the mixture of incompressible fluids based on the principle of continuum mechanics. Then, in order to find how the thermal analysis effect on the bearing performance lubricated with the mixture of multi-fluids, it will be compared to the performances between the mixture of each liquid to be blended and multi-grade engine oil as a single fluid in a high speed journal bearing. It is found that, in the case of lower viscosity oil, the difference of pressure distribution between the above two cases turns out to be existed, even if the load capacity is same level.
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고온 고전단 변형률 속도 조건에서 멀티그레이드 윤활유의 유막두께 형성 측정 연구
장시열(Siyoul Jang),김재홍(Jaehong Kim),배대윤(D. Y. Bae),유성춘(S. C. Yoo),이병옥(B. Rhee) 한국트라이볼로지학회 2005 한국트라이볼로지학회 학술대회 Vol.2005 No.11
It is important to decide the minimum film thickness and viscosity of a multigrade lubricant in a contact surface between engine composition articles. By carrying out acceleration, deceleration, and sliding-rolling ratio movement, it is experimented that film formation variations in the contact surface are measured. In order to exactly investigate the variations of a multigrade lubricant film thicknesses. optical interference images are continuously taken by high resolution CCD camera, the friction torques in a contact surface measured simultaneously as well.
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초저종횡비 나노 스케일의 탄성유체윤활 유막 두께 측정에 관한 연구
장시열,공현상 한국트라이볼로지학회 2004 한국트라이볼로지학회 학술대회 Vol.38 No.-
The measurement of ultra low aspect ratio fluid film thickness is a necessity for the verification of lubrication media characteristics and clearance design in many precision components such as MEMS, bearings and other slideways. Many technologies are applied to the measurement of ultra low aspect ratio fluid film thickness (i.e. elastohydrodynamic lubrication film thickness). In particular, in-situ optical interferometric method has many advantages in making the actual contact behaviors realized with the experimental apparatus. Careful selection of incident lights greatly enhances the fringe resolutions up to ~1.0 nanometer scale with digital image processing technology. In this work, it is found that coaxial aligning trichromatic incident light filtering system developed by the author can provide much finer resolution of ultra low aspect ratio fluid film thickness than monochromatic or dichromatic incident lights, because it has much more spectrums of color components to be discriminated according the variations of film thickness. With some measured interferometric images of ultra low aspect ratio fluid film thickness it is shown how the film thickness is resolutionized and measured in nanometer scale with digital image processing technology and space layer method.
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