3篇
您的检索式：作者名="YU Guichang"
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| 1 | Application of Computational Fluid Dynamics and Fluid Structure Interaction Techniques for Calculating the 3D Transient Flow of Journal Bearings Coupled with Rotor Systems显示文摘Journal bearings are important parts to keep the high dynamic performance of rotor machinery. Some methods have already been proposed to analysis the flow field of journal bearings, and in most of these methods simplified physical model and classic Reynolds equation are always applied. While the application of the general computational fluid dynamics (CFD)-fluid structure interaction (FSI) techniques is more beneficial for analysis of the fluid field in a journal bearing when more detailed solutions are needed. This paper deals with the quasi-coupling calculation of transient fluid dynamics of oil film in journal bearings and rotor dynamics with CFD-FSI techniques. The fluid dynamics of oil film is calculated by applying the so-called ''dynamic mesh'' technique. A new mesh movement approach is presented while the dynamic mesh models provided by FLUENT are not suitable for the transient oil flow in journal bearings. The proposed mesh movement approach is based on the structured mesh. When the journal moves, the movement distance of every grid in the flow field of bearing can be calculated, and then the update of the volume mesh can be handled automatically by user defined function (UDF). The journal displacement at each time step is obtained by solving the moving equations of the rotor-bearing system under the known oil film force condition. A case study is carried out to calculate the locus of the journal center and pressure distribution of the journal in order to prove the feasibility of this method. The calculating results indicate that the proposed method can predict the transient flow field of a journal bearing in a rotor-bearing system where more realistic models are involved. The presented calculation method provides a basis for studying the nonlinear dynamic behavior of a general rotor-bearing system. | LI Qiang YU Guichang LIU Shulian ZHENG Shuiying | 2012 | Chinese Journal of Mechanical Engineering2012，25，5： | 19 |
| 2 | Psychoacoustic Study on Contribution of Fan Noise to Engine Noise显示文摘There are more researches on engine fan noise control focusing on reducing fan noise level through optimizing fan structure,and a lot of research achievements have been obtained.However,researches on the effect of fan noise to engine noise quality are lacking.The influences of the effects of fan structure optimization on the engine noise quality are unclear.Thus,there will be a decline in fan noise level,but the deterioration of engine noise quality.Aiming at the above problems,in consideration of fan structure design and engine noise quality,an innovative method to analyze the contribution of fan noise to engine noise quality using psychoacoustic theory is proposed.The noises of diesel engine installing different cooling fans are measured by using the acoustic pressure method.The experiment results are regarded as analysis samples.The model of sensory pleasantness is used to analyze the sound quality of a diesel engine with different cooling fans.Results show that after installing 10-blade fan in medium diameter the sensory pleasantness at each test point is increased,and the increase is 13.53% on average,which indicate the improvement of the engine noise quality.In order to verify the psychoacoustical analysis,the subjective assessment is carried out.The test result shows the noise quality of engine installed10-blade fan in medium diameter is most superior.1/3 octave frequency spectrum analysis is used to study the reason of the improvement of engine noise quality.It is found that after installing proper cooling fan the sound pressure level below 400 Hz are obviously increased,the frequency assignment and spectral envelope are more reasonable and a proper cooling fan can optimize the spectrum structure of the engine noise.The psychoacoustic study is applied in the contribution of fan noise to engine noise,and the idea of engine sound quality improvement through the structure optimization is proposed. | ZHANG Junhong LIU Hai BI Fengrong NI Guangjian ZHANG Guichang LIN Jiewei YU Hanzhengnan | 2012 | Chinese Journal of Mechanical Engineering2012，25，4： | 3 |
| 3 | SARS-CoV-2-specific CD4^(+)T cells are associated with long-term persistence of neutralizing antibodies显示文摘Understanding the decay and maintenance of long-term SARS-CoV-2 neutralizing antibodies in infected or vaccinated people and how vaccines protect against other SARS-CoV-2 variants is critical for assessing public vaccination plans.Here,we measured different plasm antibody levels 2 and 12 months after disease onset,including anti-RBD,anti-N,total neutralizing antibodies,and two neutralizing-antibody clusters.We found that total neutralizing antibodies declined more slowly than total anti-RBD and anti-N IgG. | Zhongfang Wang Xiaoyun Yang Xinyue Mei Yumin Zhou Zhiqiang Tang Guichang Li Jiaying Zhong Mengqiu Yu Mingzhu Huang Xiaoling Su Bijia Lin Pengxing Cao Ji Yang Pixin Ran | 2022 | Signal Transduction and Targeted Therapy2022，7，5： | 0 |
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