检索结果-内蒙古大学图书馆

Maximum drag reduction and scale up of surfactant solution

Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2013年第9期34卷 1675-1678页

作者： Ma, Ning Xu, Na Wei, Jin-Jia Long, Yan Huang, Chong-Hai State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Turbulent drag reducing characteristics of CTAC/NaSal aqueous solution (CTAC had same mass concentration with NaSal.) were investigated in a two-dimensional channel of 30 mm height and 375 mm width, which was made of transparent acrylic resin. The measured drag reduction data were scaled up by using Hoyt's scaling method and were compared with other reported drag reduction data for different channel sizes. It could be concluded that both the critical temperature and critical Reynolds number at which turbulent drag reduction of surfactant solution occurred increased with concentration. There was a maximum drag-reduction about 60% for the measured CTAC/NaSal solutions. The Hoyt's scale-up method correlated well the experimental data for different channel heights when the SIS (shearing induced structure) was established very well in surfactant solutions.

关键词： Drag reduction

来源：评论

学校读者我要写书评

暂无评论

Bubble oscillation and effects of dynamic behaviors on forces and mass transfer in photoelectrochemical water splitting

引用

Physical Review Fluids 2024年第11期9卷 114305-114305页

作者： Yonglu She Qiang Xu Tengfei Nie Xinyi Luo Mengsha Wang Xingmiao Ye Dengwei Jing State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

The evolution and coverage of bubbles resulting from gas evolution at the reaction interface significantly impact mass transfer and the flow field within the photoelectrochemical water splitting system, posing a significant obstacle to overcoming the efficiency bottleneck of photoelectrochemical water splitting. In situ bubble observation can be realized via a coupled experimental system combining electrochemical measurements and high-speed imaging. The results indicate that bubble growth behavior correlates with system temperature and operating voltage; that is, the bubbles grow in an oscillating state on the electrode surface at the low operating voltage and high system temperature. Besides, the deviation amplitude of oscillating bubbles increases with system temperature yet decreases with operating voltage. The results indicate that the time coefficient of the growing bubble decreases, while the growth rate and gas evolution efficiency of the bubble increase with the increase of oscillating amplitude in the horizontal direction. The study of dynamic behaviors between the oscillating bubble and the contacted electrode reveals that the bubble oscillation is characterized by the periodic contraction and extension of the triple line. The mass transfer model of concentration boundary layer and the force model of oscillating bubble are constructed based on the interaction between the bubbles and the surrounding flow field. The mass transfer model has considered the microconvection caused by single-phase natural convection, gas-liquid interface expansion, and the oscillation of bubbles. Then through the force balance model, the solutal Marangoni force is found to gradually increase as the contact line extends outward.

关键词： Bubble dynamics Contact line dynamics Marangoni convection Microbubbles multiphase flows

来源：评论

学校读者我要写书评

暂无评论

On the effects of shear and compositional inhomogeneities in turbulent, lean, premixed flames 11

On the effects of shear and compositional inhomogeneities in...

引用

11th Asia-Pacific Conference on Combustion, ASPACC 2017

作者： Steinmetz, S.A. Juddoo, M. Jin, W. Masri, A.R. School of Aerospace Mechanical and Mechatronic Engineering University of Sydney NSW2006 Australia State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xian710049 China

This paper presents some initial results on the separate effects of shear and compositional inhomogeneities on the global structure of turbulent lean piloted premixed flames. Shear is introduced by injecting the mixture in two streams through two concentric tubes at different velocities. Compositional inhomogeneity, for the same shear rate, is obtained by injecting air in the annulus and fuel or rich fuel-air mixtures through the inner jet which may be recessed upstream of the jet exit plane. It is found that increasing the shear inhomogeneity can lead to a shorter flame where the tip may transition from "open" to "closed". The latter refers to a "Bunsen-like" flame while an "open" flame has reacting edges that do not close at the tip. Compositional inhomogeneity seems to have little effects on the global structure despite the presence of mixture fraction gradients a noted from Rayleigh scattering performed the jet exit plane. Measurements of velocity fields and imaging of reaction zones will be performed to enable a better understanding of the structure of these flames and to locate them on the premixed flames regime diagram. © 2018 Combustion Institute. All Rights Reserved.

关键词： Mixtures

来源：评论

学校读者我要写书评

暂无评论

Waste heat recovery in the coal-fired power generation integrated with post-combustion 3

Waste heat recovery in the coal-fired power generation integ...

引用

3rd International Conference on Electrical engineering and Mechatronics Technology, ICEEMT 2023

作者： Yang, Yali Wang, Guiwen Li, Yan Liu, Yongping Fu, Yue Liu, Ming Guoneng Jinjie Energy Co. Ltd Yulin China Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an710049 China

ISBN: (纸本)9798350303698

Post combustion systems (PCS) are a viable technology option to reduce carbon dioxide in the electricity production. However, the energy-intensive of PCC precludes its wide scale application. As for the optimization of the post combustion system, there is an optimal inlet temperature of the stripper. By optimizing the parameter of the post combustion system, the energy consumption rate of the post combustion system decreased by 1.4 GJ/t CO2 under 100% THA compared to the original post combustion system. The needed heat by the stripper shows a fall with the decrease of the unit load ratio. However, the heat changes of the post combustion system decrease with the decrease of the unit load ratio under 90% absorption rate. The efficiency penalty can be as low as 4.1% through waste heat recovery. © 2023 IEEE.

关键词： Carbon dioxide

来源：评论

学校读者我要写书评

暂无评论

Premixed combustion of diluted hydrogen-air mixtures in a constant volume bomb

Premixed combustion of diluted hydrogen-air mixtures in a co...

引用

作者： Miao, Haiyan Huang, Qian Hu, Erjiang Huang, Zuohua Jiang, Deming State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China School of Energy and Powar Engineering Xi an Jiaotong University Xi an 710049 China

Combustion characteristics of diluted hydrogen-air premixed combustion were studied in a constant volume bomb over wide ranges of diluent ratios and equivalence ratios using two kinds of diluent gases. A two-zone model was applied to calculate the heat release rate and combustion duration based on the pressure data. The study showed that, by adding diluent gas into the hydrogen-air mixture, both the combustion development duration and the combustion duration are lengthened. Increasing the diluent ratio reduces the value of the peak pressure, and the reduction is larger on the rich mixture than on the lean one. CO2 diluent gas has greater effects on the normalized mass burning rate, the combustion development duration, and the combustion duration than nitrogen. Within the experimental range of this study, the minimum value of both the combustion development duration and the combustion duration lies within the range of ø = 1.4-1.6. © 2009 American Chemical Society.

关键词： Combustion

来源：评论

学校读者我要写书评

暂无评论

Influence of Salts on Morphology of Structures in Surfactant-Polymer Solutions Explored by Coarse Grained Dynamic Simulation

Influence of Salts on Morphology of Structures in Surfactant...

引用

作者： Liu, Dongjie Liu, Fei Zhou, Wenjing Chen, Fei Wei, Jinjia State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an710049 China

In this study, a coarse-grained molecular dynamic simulation was employed to test the influence of salts in morphology of structures in surfactant-polymer solutions. The surfactant was cetyltrimethyl ammonium chloride (CTAC) and the polymer was polyacrylamide (PAM). Six different salt concentrations were studied in the mixed surfactant-polymer solutions, and pure surfactant solutions with salts were also tested as control groups. By analyzing the shapes of micelles and the CTA+ aggregation number of micelles, we noted that the proper salt concentration can facilitate the formation of large micelles. In too high or too low salt concentration solutions only spherical or short rodlike micelles exist. The existence of PAM can also facilitate the formation of large micelles because polymers act as "bridges" and increase the probability of touch and coalescence of micelles. © Springer Nature Switzerland AG 2020.

关键词： Morphology

来源：评论

学校读者我要写书评

暂无评论

Energy saving analysis of the natural gas gathering: A case study

Energy saving analysis of the natural gas gathering: A case ...

引用

26th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2013

作者： Wei, Qingyu Cao, Fei Zhu, Xule Zhao, Liang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China Management Committee of Economic Development Zone Qingshan District Wuhan China

In the petroleum refining industry, the fossil fuel used by the atmospheric and vacuum distillation units takes large proportion to the plant-self energy consumption. It is necessary to optimize the system for the energysaving consideration. In this study, the exergy analysis method was utilized to optimize the gas collecting system. It is found that, the water bath furnace was a weak link, so we must improve inlet temperature of the fuel and reduce the number of excess air to enhance the economy of the system and reduce the exergy loss.

关键词： Fossil fuels

来源：评论

学校读者我要写书评

暂无评论

Performance comparison and analysis of typical energy conversion cycle

Performance comparison and analysis of typical energy conver...

引用

International Conference on Computer Distributed Control and Intelligent Environmental Monitoring

作者： Wang, Yuqi Zheng, Lan Yang, Fusheng Meng, Xiangyu Zhang, Zaoxiao School of Chemical Engineering Northwest University Xi'an Shaanxi 710069 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an Shaanxi 710049 China

ISBN: (纸本)9780769543505

The performance of 3 types of energy utilization cycles including the organic Rankine cycle, the single stage static hydrogen compression cycle, and the new multistage continuous hydrogen compression cycle were analyzed. A multi-element valued model was used to evaluate the performance holistically, and the result showed that the integrated superiority achieved 0.721, which indicated the continuous hydrogen compression cycle is considered the best option among the typical compression energy utilization cycles and deserves thorough studying. © 2011 IEEE.

关键词： Energy utilization

来源：评论

学校读者我要写书评

暂无评论

CFD study on the optimal nozzle exit position in a CO2 two-phase ejector 24

CFD study on the optimal nozzle exit position in a CO2 two-p...

引用

24th IIR International Congress of Refrigeration, ICR 2015

作者： He, Yang Deng, Jianqiang Zhang, Zaoxiao Zheng, Lixing State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an710049 China

ISBN: (纸本)9782362150128

The nozzle exit position (NXP) is a significant parameter for an ejector. In this work, a two dimensional (2D) homogeneous CFD model is developed to simulate the two-phase ejector used in transcritical CO2 refrigeration cycle and NXP is focused on. After model validation, the flow fields in ejectors with different NXPs are simulated and an optimal NXP is obtained. According to the numerical results, with the increase of the NXP, a higher velocity and lower pressure are achieved for the primary fluid in the suction chamber which enhances the entrainment of the secondary fluid. Oppositely, the flow area of the primary fluid at the mixer inlet increases with the NXP which reduces the secondary flow rate. A compromise between these two factors leads to the optimal NXP with the highest entrainment ratio under the same operating condition. The results are helpful to the optimal design and control of the ejector.

关键词： Carbon dioxide

来源：评论

学校读者我要写书评

暂无评论

Hot corrosion behavior of TP347HFG without and with external stresses in molten salts

Hot corrosion behavior of TP347HFG without and with external...

引用

International Conference on power engineering, ICOPE 2015

作者： Fu, Jiapeng Zhou, Qulan Li, Na Liu, Zhuhan Liu, Taisheng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Dongfang Boiler Group Corporation Limited Zigong643000 China

The hot corrosion tests of the austenitic TP347HFG in molten sulfates with and without external stresses were conducted at 700 and 750 oC. The corroded specimens of different conditions were investigated through measurements of o xide morphology, corrosion thickness and composition. Through the analysis to the corrosion specimens, we knew that the corrosion reaction of the alloy was strongly related to the formation of an oxidation progress of metallic elements. The unstressed specimens had more complex products and thicker corrosion layers than those under 20MPa external stresses at 700 and 750 oC, which meant mo re fierce corrosion behaviors. It seemed that the applied stress led to a faster formation of a continuous, dense oxides layer that protected the inner specimens fro m further corrosion reaction. Generally, the exertion of the stresses caused many micro cracks and defects in the metal. These defects acted as faster and easier diffusion paths for the Cr atoms to diffuse to the surface, and thus, promote a faster formation of the protective Cr2O3 oxide layer. © 2015 The Japan Society of Mechanical Engineers.

关键词： Austenitic stainless steel

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：