检索结果-内蒙古大学图书馆

Investigation on the impact of the environment wind velocity on the indirect air-cooling tower performance

AIP Conference Proceedings 2013年第1期1547卷 469-476页

作者： Yongbo Qin Hongfang Gu Haijun Wang Guoyong Chen State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University 710049 Xi'an China

The wind velocity plays a crucial role in the operation characteristic of indirect cooling tower. In this paper a 2×330MW vertical arrangement indirect air-cooled system was taken as research object, and numerical simulation method was used to analyze the relative influence of the wind speed, ranging from 4m/s to 18m/s, on the outlet water temperature of cooling tower, the outlet air temperature of radiator, the facing wind speed of the fan segment and on the outlet air speed of the cooling tower. The result shows that the impact of the natural wind speed on the cooling tower efficiency varies greatly and this impact increases as the wind speed increases.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Study on heat transfer characteristic of ethanol-water mixture condensation on a vertical micro-tube

引用

AIP Conference Proceedings 2013年第1期1547卷 362-372页

作者： Xiping Chen Jinshi Wang Junchao Qin Daotong Chong Junjie Yan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University 710049 Xi'an China

In present experiment, the vapor mixture with different velocities (2m⋅s−1, 4m⋅s−1) and different ethanol mass fraction (0.5%, 1%, 2%, 5%, 10%, 20%, 50%) flew through vertical micro-tube and condensed on the outer tube surface at pressure 31.16kPa, 47.36kPa. The condensation modes were observed by CCD camera, and the characteristics of the heat transfer coefficients versus the vapor-to-surface temperature differences for different experimental conditions were obtained. The condensation heat transfer coefficients of vapor mixture decrease with the vapor concentration increasing. The maximum peak value of heat transfer coefficients, up to 39 kW⋅m−2⋅K1, which was about 3-4 times greater than that of steam, appeared when the ethanol mass fraction was 2%. A heat transfer coefficient correlation including the effects of all the tested parameters is proposed by using the multiple linear least squares method based on the experimental data. The calculated values agreed well with the experimental data and the deviations between them were from −20% to 20%.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Optimization research on the structure of horizontally-arranged indirect air-cooling tower under strong wind condition

引用

AIP Conference Proceedings 2013年第1期1547卷 454-462页

作者： Guoyong Chen Hongfang Gu Haijun Wang Yongbo Qin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University 710049 Xi'an China

Strong wind has a significant impact on the heat radiation of the air-cooling system. In this research, a numerical calculation model of 2×1000MW horizontally arranged air-cooling tower is established to simulate the flow distribution and heat exchanging capability of three different structures-horizontally-arranged indirect air-cooling tower, tower with guide wall outside, and tower with a cross wall inside-under high-speed wind and extreme-speed wind conditions. The result reveals that the structure with the guide wall outside the tower only works under strong wind condition while the structure with cross wall inside shows the anti-wind capability under both high-speed wind and extreme-speed wind conditions.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A kinetic modeling study of high temperature chemistry of n-pentanol 8

A kinetic modeling study of high temperature chemistry of n-...

引用

8th US National Combustion Meeting 2013

作者： Li, Qianqian Merchant, Shamel S. Green, William H. Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'n Jiaotong University Xi'an710049 China Department of Chemical Engineering Massachusetts Institute of Technology CambridgeMA02139 United States

ISBN: (纸本)9781627488426

With increasing environmental deterioration and energy demand, studies on new alternative fuels have been attracting more attention. N-pentanol is a five carbon, straight-chain alcohol, which can be produced through natural microbial fermentation and/or engineered microorganisms. It has many advantages over lower carbon alcohols, including higher energy density, lower vapor pressure and better fuel compatibility. In this study, a detailed reaction mechanism of n-pentanol, on the basis of a previously proposed n-butanol mechanism, is generated using the open-source software Reaction Mechanism Generator (RMG). High temperature chemistry of the mechanism was validated against recently published laminar flame speeds and ignition delays. Encouraging results between simulations and experiments were observed under most conditions. Simulations were also conducted using a recently developed n-pentanol oxidation mechanism (NUI model) by Heufer et al. For lean mixtures, the two mechanisms show similar results, while the RMG model yields better predictions for rich mixtures and at an elevated pressure. Reaction pathways and sensitivity analysis reveal the key differences between the two mechanisms in terms of intermediates formed and fuel consumption.

关键词： Alternative fuels

来源：评论

学校读者我要写书评

暂无评论

Effect of equivalence ratio on the ignition delay times of propane/hydrogen in argon diluted oxygen

Effect of equivalence ratio on the ignition delay times of p...

引用

9th Asia-Pacific Conference on Combustion, ASPACC 2013

作者： Tang, Chenglong Man, Xingjia Pan, Lun Huang, Zuohua State Key Laboratory of Multiphase Flows in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

By using the shock tube facility, measurements on ignition delay times of propane/hydrogen mixtures (hydrogen fraction from 0 to 100%) were conducted for the equivalence ratio of 0.5, 1.0 and 2.0. Results show that for XH2 less than 70%, ignition delay time shows a strong Arrhenius temperature dependence, and the ignition delay time increases with the increase of the equivalence ratio. When XH2 is increased to more than 95%, the ignition delay times do not retain the Arrhenius temperature dependence any more, and the effect of the equivalence ratio is very weak. Numerical studies were made using the selected kinetic mechanisms and results show that the predicted ignition delay time gives a reasonable agreement with the measurements at all test conditions. Both measurements and predictions show that for X H2 less than 70%, the ignition delay time is only moderately decreased with the increase of XH2, indicating that hydrogen addition has weak effect on ignition enhancement. Sensitivity analysis reveals the key reactions that control the simulation of ignition delay time. Kinetic study is made to interpret the ignition delay time dependence on equivalence ratio and XH2.

关键词： Hydrogen

来源：评论

学校读者我要写书评

暂无评论

Experimental study on performance and emissions of diesel/n-pentanol blends on a DI diesel engine

Experimental study on performance and emissions of diesel/n-...

引用

9th Asia-Pacific Conference on Combustion, ASPACC 2013

作者： Wei, Liangjie Cheung, C.S. Huang, Zuohua Department of Mechanical Engineering Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

In this work, experiments were conducted on a diesel engine fueled with n-pentanol/diesel blends to examine the effect of n-pentanol addition on the engine performance and emissions. Results show that, the addition of n-pentanol to diesel increases the brake specific fuel consumption and has little effect on the brake thermal efficiency. Additionally, the emissions of HC, CO and NOx are slightly increased with the increase of n-pentanol in the fuel blends, however, the particulate matter emission is significantly reduced.

关键词： Brakes

来源：评论

学校读者我要写书评

暂无评论

Visualization and flow boiling heat transfer of hydrocarbons in a horizontal tube

引用

AIP Conference Proceedings 2013年第1期1547卷 432-441页

作者： Zhuqiang Yang Qincheng Bi Yong Guo Zhaohui Liu Jianguo Yan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Visualizations of a specific hydrocarbon fuel in a horizontal tube with 2.0 mm inside diameter were investigated. The experiments were conducted at mass velocity of 213.4, 426.5 and 640.2 kg/ (m2⋅s), diabatic lengths of 140, 240 and 420 mm under the pressure from 2.0-2.7 MPa. In the sub-pressure conditions, bubbly, intermittent, stratified-wave, churn and annular flow patterns were observed. The frictional pressure drops were also measured to distinguish the patterns. The development of flow patterns and frictional pressure drop were positively related to the mass velocity and the heat flux. However, the diabatic length of the tube takes an important part in the process. The residence time of the fluid does not only affect the transition of the patterns but influence the composition of the fuel manifested by the fuel color and carbon deposit. The special observational phenomenon was obtained for the supercritical pressure fluid. The flow in the tube became fuzzier and pressure drop changed sharply near the pseudocritical point. The flow boiling heat transfer characteristics of the hydrocarbons were also discussed respectively. The curve of critical heat flux about onset of nucleate boiling was plotted with different mass velocities and diabatic tube lengths. And heat transfer characteristics of supercritical fuel were proved to be better than that in subcritical conditions.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Pool boiling heat transfer on ultra-light porous metal foam surfaces

Pool boiling heat transfer on ultra-light porous metal foam ...

引用

2013 International Conference on Materials for Renewable Energy and Environment, ICMREE 2013

作者： Ji, Xianbing Xue, Qiang Xu, Jiliang Xu, Jia State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China Beijing Key Laboratory of Multiphase Flow and Heat Transfer North China Electric Power University Beijing China

ISBN: (纸本)9781479933365

Experiments were conducted to study pool boiling heat transfer on ultra-light porous metal foam surfaces, with deionized water as working fluid. The metal foams have pore densities from 30 to 60ppi (pores per inch) and thickness from 2.0 to 5.0mm. The effects of heat flux, surface superheat, liquid temperature and characteristic parameters of metal foam on pool boiling heat transfer were investigated. It is found that metal foam surfaces can significantly enhance pool boiling heat transfer and lower the surface superheat at the boiling incipience. Pore density and thickness exists an optimal value to strengthen boiling heat transfer. The boiling heat transfer coefficient on the metal foam surfaces is about 2∼3 times of those on the plain surfaces. The significant reasons are due to the distinct nature of high porosity and multi-scale pore sizes of metal foams. The larger pores help to release the created vapor while the smaller pores help to suck the liquid toward the heater surface, decreasing the shear stress at the vapor-liquid interface for the counter-current flow. © 2013 IEEE.

关键词： Heat transfer

来源：评论

学校读者我要写书评

暂无评论

Stability analysis of a square rod bundle sub-channel in supercritical water reactor

引用

AIP Conference Proceedings 2013年第1期1547卷 181-189页

作者： Wang Hai-jun You Ting Zhang Lei Gu Hong-fang Luo Yu-shan Bian Ji-lian State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiao tong University Xi'an 710049 China

Extensive investigations on the flow and heat transfer behavior in SCWR fuel assembly have been undertaken worldwide. However, stability analysis of supercritical water in the sub-channels of tight lattices is still lacking. In this paper, the flow stability of a fuel bundle channel with square pitches has been analyzed using commercial CFD code-ANSYS Fluent. Typical dynamic instability of Density Wave Oscillation (DWO) has occurred in heated channel containing fluids at supercritical pressure. A further discussion about the impacts of various operational parameters (e.g. power input, system pressure, mass velocity, inlet temperature, etc) shows that the system becomes more stable as system pressure and/or mass flow rate increases. An increase in inlet temperature also has a stabilizing effect on the system.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Numerical simulation of the multi-component slurry gasification with the non-premixed combustion model

Numerical simulation of the multi-component slurry gasificat...

引用

2013 Spring International Conference on Material Sciences and Technology, MST-S 2013

作者： Li, Xing Xing Yi, Chun Hai Yang, Bo Lun Zhang, Yong Men, Chang Gui He, Gen Liang Xu, Hong Dong Department of Chemical Engineering State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 China Northwest Research Institute of Chemical Industry Xi'an Shaanxi 710049 China

ISBN: (纸本)9783037857090

Considering the volumetric reactions and particle surface reactions in an entrained flow gasifier, the non-premixed combustion model based on the wet particles combustion method is adopted to simulate the multi-component slurry gasification process with FLUENT software. The velocity, temperature and concentration profiles of the gas products in the gasifier are obtained. Simulated results agree well with the commercial data, which verified the validity and applicability of the present model. Simultaneously, the reaction subarea in the gasifier has turned out to be obvious, the water evaporation, volatiles cracking and combustion reactions mainly appear in the jet region of the gasifier, the char gasification mainly appear in the freeboard region, but few reactions appear in the recirculation region. Moreover, with the increase of the mass fraction of the multi-component slurry, the content of the syngas at the gasifier outlet increases, while with the oxygen carbon atom ratio increasing, the syngas yield is rising early but declining later. © (2013) Trans Tech Publications, Switzerland.

关键词： Surface reactions

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：