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이안성(An Sung Lee),박무룡(Moo Ryong Park),김영철(Young Cheol Kim) 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.36 No.-
In this study is presented a general Galerkin-FE gas lubrication analysis method. Then, the method is applied to analyze spiral groove dry gas seals particularly for low-speed mixer applications, where their maximum rotating speeds are 500 rpm. Results show that a spiral groove seal with an additional inner circular groove performs slight better than its counterpart without the inner groove for opening force but only at the expense of more leakage.
내부 원형 그루브를 갖는 저속 드라이 가스 시일의 윤활 성능해석
이안성(An Sung Lee),김준호(Jun Ho Kim) 한국트라이볼로지학회 2004 한국트라이볼로지학회 학술대회 Vol.39 No.-
In this study a general Galerkin FE lubrication analysis method was utilized to analyze the complex lubrication performance of a spiral groove seal having an additional inner circular groove, which was designed for a chemical process mixer operating at a low speed of the maximum 500 rpm. Equilibrium seal clearance analyses under varying outer pressure revealed that the seal maintains a certain levitation seal clearance under the outer pressure of more than about 1.5 bar, regardless of a rotating speed. Also, under the normal outer pressure of 11 bar, the axial stiffness of the seal was predicted to have a high value of more than 7.0e+07 N/m, regardless of a rotating speed and thereby, the seal is expected to maintain a stable thickness of lubrication film under a certain external excitation acting.
이안성(An Sung Lee),이동환(Dong Whan Lee),나언주(Uhn Joo Na) 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.36 No.-
In high-speed gas-levitation applications a high compressibility number often brings a numerical difficulty in predicting generated pressure profiles by causing erroneous sudden pressure overshootings and oscillations in the trailing-edge. To treat the problem, in this study an exact exponential high-order shape function is introduced in the FE lubrication analyses. It is, shown by various examples that the high-order shape function scheme can subdue successfully pressure overshootings and oscillations.
프로세스 압축기 틸팅패드 저널베어링의 비정상 고온거동 트러블슈팅
이안성(An Sung Lee),이운실(Woonsil Lee),최동훈(Dong-Hoon Choi) 한국트라이볼로지학회 2017 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.33 No.2
A DE-side LBP tilting pad journal bearing of a 1-stage overhung heat-pump compressor in a propylene process exhibited abnormal high-temperature behavior. Its temperature had been relatively high at 78 °C from the beginning of operation. In 2014, after three years of operation, it increased suddenly and reached 103 °C. Installing a varnish removal equipment and others managed to stabilize the temperature at 95 °C. We undertook a troubleshooting approach for reviewing the comprehensive status and integrity of the temperature design of the bearing. We performed lubrication and heat-balance analysis, based on the design engineering data and documents supplied by the OEM. For the base design data of DE-side TPJB, evaluating the effects of key design variables on bearing metal temperature showed that firstly, increasing the bearing clearance and supply oil flow-rate, and next, changing the oil type, and finally, increasing the machined pad clearance and offset, are more effective in reducing the bearing metal temperature. Furthermore, a clarification meeting with the OEM revealed that an incorrect decision had been made to decrease the bearing clearance to eliminate the SSV harshness issue, while not maintaining a sufficient oil flow-rate. We conducted a detailed retrofit design analysis, wherein we increased the oil flow-rate and bearing clearance by decreasing the preload. We predicted that the bearing temperature would decrease to 63 °C from 75.7 °C even at the rerate condition. Finally, after installing and operating a retrofit replacement bearing in 2015, the bearing temperature stabilized at a low temperature of 65 °C. Currently (January. 2017), two year later, the bearing metal temperature remains at 65 °C. Therefore, we can conclude that the abnormal high-temperature behavior of the bearing has been resolved completely.
내부 원형 그루브를 갖는 저속 드라이 가스 시일의 윤활 성능해석 및 실험
이안성(An Sung Lee),김준호(Jun Ho Kim) 한국트라이볼로지학회 2005 한국윤활학회지(윤활학회지) Vol.21 No.2
In this study a general Galerkin FE lubrication analysis method was utilized to analyze the complex lubrication performance of a spiral groove seal having an additional inner circular groove, which was designed for a chemical process mixer operating at a low speed of the maximum 500 rpm. Equilibrium seal clearance analyses under varying outer pressure revealed that the seal maintains a certain levitation seal clearance under the outer pressure of more than about 1.5 bar, regardless of a rotating speed. Also, under the normal outer pressure of 11 bar, the axial stiffness of the seal was predicted to have a high value of more than 7.0 e + 07 N/m, regardless of a rotating speed and thereby, the seal is expected to maintain a stable thickness of lubrication film under a certain external excitation acting. A seal levitation test rig was designed and constructed. Experimental results at 500 rpm agreed well with analytical predictions and the applied lubrication analysis method was verified.
이안성(An Sung Lee),김준호(Jun Ho Kim) 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.37 No.-
In this study a general Galerkin FE formulation of the incompressible Reynolds equation is derived for lubrication analyses of noncontacting mechanical face seals. Then, the formulation is applied to analyze the flexibly mounted stator-type reactor coolant pump seals of local nuclear power plants, which have deep straight grooves or plane coning on their primary seal ring faces. Their various lubrication performances have been predicted. Results show that the analyzed deep straight groove seal should have a net coning of less than 0.6 tim to satisfy the leakage limit. And for the same amount of equilibrium opening force the plane coning seal requires to have a 3 times higher dimensionless coning than the deep straight groove seal.
고속비행체용 스파이럴 그루브 드라이 가스 시일의 윤활 성능해석
이안성(An Sung Lee),김준호(Jun Ho Kim) 한국트라이볼로지학회 2005 한국윤활학회지(윤활학회지) Vol.21 No.1
In this study a general Galerkin FE lubrication analysis method is utilized to analyze the complex lubrication performance of a spiral groove seal, which is being designed and developed for a high-speed flying object application operating at a high-speed of over 50,000 rpm. As at the equilibrium seal clearance the axial stiffness of the seal is predicted to have almost such a constant high value of 1.04 × 10^8 N/m regardless of a rotating speed, the seal is expected to maintain a stable thickness of lubrication film under a certain external excitation acting. Also, as even at an ultra high-speed of 80,000 rpm the axial damping of the seal is shown to have a relatively high value of 5,775 N-s/m, the dynamic stability of the seal system at the axial degree of freedom is assured well enough.
LPG액상분사식용 외장형 연료펌프 캐리어의 스파이럴그루브 액체시일의 윤활특성
이안성(An Sung Lee),김창업(Chang Up Kim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
In this study, to improve fundamentally a poor lubrication durability of critical component carrier at its suction face in a external fuel pump for LPLi fuel system, a spiral groove seal design has been adopted, which can be applied at a low viscosity of liquid LPG. Utilizing the Galerkin finite element lubrication analysis method a lubrication characteristic analysis of the seal has been carried out in detail, and its lubrication performance optimization has been performed by systematic parameter study. Compared to a reference design, a final optimized spiral groove seal design has shown the result of increasing a groove depth by 66.7% to 2.5 ㎛ while increasing an equilibrium seal clearance by 65.3%. It has been predicted from the analysis that at the equilibrium condition between the closing force of pumping pressure and the seal opening force, the optimally designed carrier spiral groove liquid seal is capable of maintaining a stable lubricating film with an axial stiffness coefficient of 3.376×10? N/M and operating in noncontact and in addition leakage through the seal is very minimal.t here. Put Abstract here. Put Abstract here. Put Abstract here. Put Abstract here. Put Abstract here. Put Abstract here.
이안성(An Sung Lee) 한국트라이볼로지학회 2012 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.28 No.6
In the preceding Part I study, for improving the unbalance response vibration of a large PRT motorgenerator rotor fundamentally by design, a series of design analyses were carried out for bearing improvement by retrofitting from original plain partial journal bearings, applied for operation at a rated speed of 1,800 rpm, to final tilting pad journal bearings. To satisfy evenly key basic lubrication performances such as the minimum lift-off speed and maximum oil-film temperature, a design solution of 5-pad tilting pad journal bearings and maximizing the direct stiffness by about two times has been achieved. In this Part II study, a detailed rotordynamic analysis of the large PRT motor-generator rotor-bearing system will be performed, applying both the original plain partial journal bearings and the retrofitted tilting pad journal bearings, to confirm the effect of rotordynamic vibration improvement after retrofitting. The results show that the rotor unbalance response vibrations with the tilting pad journal bearings are greatly reduced by as much as about one ninth of those with the plain partial journal bearings. In addition, for the tilting pad journal bearings there exist no critical speed up to the rated speed and just one instance of a concerned critical speed around the rated speed, whereas for the plain partial journal bearings there exist one instance of a critical speed up to the rated speed and two instances of concerned critical speeds around the rated speed.