期刊：
Computer Modelling and New Technologies,2014年18(11):1340-1345 ISSN：1407-5806
通讯作者：
Yuan, Fengwei
作者机构：
[Yuan, Fengwei; Zou, Jiazhu; Deng, Qian] College of Mechanical Engineering, University of South China, Hengyang, Hunan, China
摘要：
A numerical simulation for heat exchanger with continuous helical baffles was carried out. The study focuses on the effects of helix angle on flow and heat transfer characteristics, and heat exchanger performance is evaluated by entropy generation number based on the analysis of the second law of thermodynamics. The results show that both the shell-side heat transfer coefficient and pressure drop decrease with the increase of the helix angle at certain mass flow rate. The latter decreases more quickly than the former. The tangential velocity distribution on shell-side cross section is more uniform with continuous helical baffles than with segmental baffles. The axial velocity at certain radial position decreases as the helix angle increases in the inner region near the central dummy tube, whereas it increases as the helix angle increases in the outer region near the shell. The heat exchange quantity distribution in tubes at different radial positions is more uniform at larger helix angel.
作者机构：
[Deng, Qian; Wang, Yuling; Yuan, Fengwei] Univ South China, Coll Mech Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Yuan, Fengwei] U;Univ South China, Coll Mech Engn, Hengyang 421001, Hunan, Peoples R China.
会议名称：
4th International Conference on Advances in Materials and Manufacturing (ICAMMP 2013)
会议时间：
DEC 18-19, 2013
会议地点：
Kunming, PEOPLES R CHINA
会议主办单位：
[Yuan, Fengwei;Deng, Qian;Wang, Yuling] Univ South China, Coll Mech Engn, Hengyang 421001, Hunan, Peoples R China.
会议论文集名称：
Advanced Materials Research
关键词：
Fault diagnosis;Hidden markov model (HMM);Nuclear facilities
摘要：
Due to the complex structure of nuclear facilities in a high irradiation environment, people were hard to approach it, In view of these situation a fault diagnosis method based on HMM(Hidden Markov Model) of capturing the audio signal while facilities were operating was proposed. With the strong modeling ability, HMM could be applied to analyzing such as audio signal non-stationary time signal. By using this method, the original mechanical structures of nuclear facilities were not destroyed. The preposed sensors were needed as few as possible by the whole diagnosis system and which had a simple structure, low cost structure, the fault diagnosis rate was high and so on. State monitoring and fault diagnosis system of complex nuclear ower equipment could timely and effective to provide running status and potential failure information for operating personnel, which had a vital significance for the safe and reliable operation of nuclear power equipment.
期刊：
ADVANCES IN CIVIL AND STRUCTURAL ENGINEERING III, PTS 1-4,2014年501-504:2338-2343 ISSN：1662-7482
通讯作者：
Qing, Defan
作者机构：
[Wang, Cuifang; Qing, Defan; Zhang, Yalong; Liu, Shengxue] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Qing, Defan] U;Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
会议名称：
3rd International Conference on Civil Engineering and Transportation (ICCET 2013)
会议时间：
DEC 14-15, 2013
会议地点：
Kunming, PEOPLES R CHINA
会议主办单位：
[Qing, Defan;Zhang, Yalong;Liu, Shengxue;Wang, Cuifang] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
会议论文集名称：
Applied Mechanics and Materials
关键词：
spiral surface channel;combination vortex generator;optimum structure;enhanced heat transfer
摘要：
The array configuration of delta wing and elliptical cylinder vortex generator in the spiral surface channel was studied. By changing the assembly distance s, the triangle wing vortex generator angle of attack alpha, the elliptical cylinder vortex generator angle of attack beta to research the heat transfer and resistance properties under different working conditions. The research model as follow: the heat-medium is water-vapor [H2O], the cold medium of flow is air, Steam temperature is 400K and air inlet temperature is 293K, the Reynolds number ranging from 4000 to 7000.The optimum structure was determined by using numerical simulation method and orthogonal experiment method. The result shows the optimization structure of the combination vortex generator: alpha=45 degrees, beta=45 degrees, s=90mm. Compared with the normal structure, the heat transfer enhancement comprehensive effect of the optimization structure raised about 36.2%similar to 47.6%.
摘要：
The effects of Cu addition on the microstructure and mechanical properties of the as-cast magnesium alloy ZK60 were investigated with optical microscope, SEM, TEM, XRD, EPMA and tensile tester. The mechanism by which the mechanical properties are affected by Cu addition was discussed. The results show that Cu can effectively eliminate the intragranular solute segregations in the alloy, and the grain size of the alloy is decreased considerably with increasing the Cu amount. A ternary eutectic phase MgZnCu with a face-centered cubic structure is identified in the Cu-bearing alloys, which predominantly distributes at the grain boundary and acts as the nucleation sites of microcracks during the plastic deformation process. It is also found that the tensile properties of the alloy firstly increase by the trace addition of 0.5%-1%Cu and then decrease by a further addition up to 2.0%.
