http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Chengwei Fei (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
Dan Sun,Shengyuan Li,Chengwei Fei,Yanting Ai,Rhea. P Liem 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1
The cavitation phenomenon in journal bearing and journal whirl are considered to evaluate the static and dynamic characteristics of journal bearing, to be more consistent with the actual operating conditions of journal bearing. With a 3D CFD method, the cavitation and journal whirl are simulated by adopting mesh deformation technique and mixture phase-change model. By comparing the results with those of the traditional Reynolds equation, we observe that first, the phenomena of cavitation and journal whirl are very consistent with the actual operating conditions of journal bearing. Moreover, for single-phase and two-phase flow models, the distribution features of oil film pressure are similar in convergent wedge zone while largely different in divergent part of the gap. The oil film pressure and vapor phase volume fraction notably vary on different whirl positions of the journal. We also observe that as whirl frequency increases, the oil film force gradually increases and the stability of journal bearing decreases rapidly before reaching a plateau. The efforts of this paper provide an efficient method to accurately evaluate the static and dynamic characteristics of journal bearing and offer a useful insight into the accurate analysis and design of journal bearing.
-
Dan Sun,Xudong Wang,Chengwei Fei,Shuang Wang,Yanting Ai 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9
This paper proposes a new type of negative dislocated seal (NDS) based on the dislocated bearing theory to investigate the influential parameters of static rotor eccentricity and dislocated ratio on the static and rotordynamic characteristics of an example seal solved with computational fluid dynamics (CFD) the flow field. The rotordynamic characteristics of the NDS were investigated in respect of the effects of rotor whirling frequency on response force, stiffness coefficients, damping coefficients and rotor system stability, by multifrequency elliptical orbit rotor whirling model. Based on the studies, we reached the following conclusions. The circumferential pressure distribution of NDS and conventional labyrinth seal (LS) presents sine periodic variation approximately, while relative to the LS, the NDS has two divergent wedge gaps and reduces the hydrodynamic pressure effects, then the circumferential pressure difference and tangential force on rotor surface decreases by about 40 %~190 %. The leakage of the NDS linearly increases with the rising eccentricity ratio and dislocation ratio approximately, and is larger (about 0.9 %~1.5 %) than the LS. The direct stiffness coefficients of the two seals increase with the rise of rotor whirling frequency, while the absolute values of both the cross-coupled stiffness coefficients and the damping coefficients decrease with raising rotor whirling frequency. Compared with the LS, the NDS has smaller (about 28.8 %~206.2 %) cross-coupled stiffness coefficient, larger (about 26.15 %~60.39 %) effective damping coefficient, and good stability of rotor system. This study has developed a novel seal structure to improve the seal performance of turbomachinery such as aeroengine.
-
A novel preparation and formation mechanism of carbon nanotubes aerogel
Li Shaolong,He Yan,Jing Chengwei,Gong Xiubin,Cui Lianlei,Cheng Zhongyue,Zhang Chuanqi,Nan Fei 한국탄소학회 2018 Carbon Letters Vol.28 No.-
A novel, unique, and effective method for carbon nanotube (CNT) dispersion by the free arc stimulation is proposed. CNTs are introduced as an aerogel into the air space via the dispersion method and can be utilized as a solution by adding it to solvents. The volume of the original generated CNT aerogel with a high-volume expansion ratio displays a performance two orders of magnitudes better than that of raw CNTs, which is considered a powerful characterization of the dispersion effect. The CNT aerogel, which was observed by scanning electron microscopy also showed a satisfactory dispersion morphology. Its structure and properties were tested before and after dispersion by Raman spectroscopy and great consistency was observed, which proved that the CNTs were undamaged. This approach may greatly promote the large-scale application of CNTs.
ScienceON
스콜라연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
