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Experimental Study on Condensation Heat Transfer Characteristics inside an Inclined Wave-Finned Flat Tube of Direct Air-Cooling System

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Journal of Thermal Science 2021年第2期30卷 432-440页

作者： WANG Haitao TAO Tao MEI Xuesong WANG Haijun GU Hongfang State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong UniversityXi'an 710049China Shaanxi Key Laboratory of Intelligent Robots School of Mechanical EngineeringXi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

In this paper,the condensation heat transfer characteristics of parallel flow and counter flow inside an inclined wave-finned flat tube is investigated *** condensation heat transfer coefficients are analyzed based on the experimental *** of experiments show that condensation heat transfer coefficient decreases as the temperature difference Δt=ts-tw increases and mass flow rate *** parallel flow has a similar development with the counter flow,and the condensation heat transfer coefficient of counter flow is less than that of parallel flow under the same air cooling *** addition,condensation heat transfer coefficient correlations are also obtained under experimental *** calculations agree well with the measured data and the agreement is seen to be within ±4% for the parallel flow and ±5% for the counter flow.

关键词： condensation heat transfer wave-finned fiat tube modified model parallel flow counter flow

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Experimental study on the CO-SCR performance of honeycomb-based Fe-Cu/RHA catalyst

Experimental study on the CO-SCR performance of honeycomb-ba...

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International Conference on power engineering 2021, ICOPE 2021

作者： Pan, Yuqing Li, Na Wen, Du Ran, Shiyuan Wu, Chenyang Zhou, Qulan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University China

The combustion process of carbon-based fuels will produce CO. If CO can be used as a reducing agent to remove NO, the goal of removing NO and unburned carbon (UBC) simultaneously can be achieved. When rice husk ash (RHA) rich in amorphous SiO2 is used to support Fe-Cu metal oxides, its huge specific surface area and non-lattice microstructure can reduce the reaction temperature, so that Fe-Cu/RHA catalyst has a high performance of selective catalytic reduction of NO by CO (CO-SCR). The paper used honeycomb ceramic to support Fe-Cu/RHA catalyst, and studied the effects of preparation method, active ingredient loading and reaction conditions on the CO-SCR performance of integral catalyst. The experimental results showed that the integral catalyst obtained by the heating and stirring method was better than the room temperature method. The conversion rates of CO and NO of the integral catalyst increased with the increase of the active ingredient loading. Besides, the oxygen concentration had little effect on the conversion rates of NO and CO. The conversion rate of CO to CO2 increased with the increase of temperature, and it could reach up to 98%. The conversion rate of NO to N2 fluctuated slightly as the temperature increased. © 2021 The Japan Society of Mechanical Engineers.

关键词： Selective catalytic reduction

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Experimental Study on Preparation of Amorphous SiO2 by Fluidized Bed Combstion of Rice Husk

Experimental Study on Preparation of Amorphous SiO2 by Fluid...

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International Conference on power engineering 2021, ICOPE 2021

作者： Tan, Jingkao Zhou, Qulan Yao, Yashu Li, Na State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University China

Rice husk ash contains SiO2 with a mass fraction of 87%-97%. Through controlled combustion under suitable conditions, SiO2 in rice husk ash will be amorphous, with high activity and rich porosity, which can be applied to construction, silicon preparation and adsorption *** it is necessary to study the effects of combustion parameters on the quality of RHA. Compared to conventional boiler furnace, the fluidized bed combustor has a lower combustion temperature and a longer residence time, which is suitable for the production of high quality amorphous rice husk ash. In this thesis, the effects of fluidized bed combustion parameters on the quality of RHA will be studied to provide guidance for amorphous SiO2 preparation by combustion control in boiler. On the existing 15kw bench-scale fluidized bed system, experiments were made to study the effects of fluidized bed combustion parameters on the quality of RHA. The rice husk combustion curve was comprehensively depicted, and the rice husk ash was analyzed by BET analysis, XRD scanning and thermogravimetric analysis. Therefore, the casual relationship between rice husk combustion process and RHA quality was evaluated comprehensively. © 2021 The Japan Society of Mechanical Engineers.

关键词： Quality control

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CFD simulation of thermal hydraulic characteristics in a typical upper plenum of RPV

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Frontiers in Energy 2021年第4期15卷 930-945页

作者： Mingjun WANG Lianfa WANG Yingjie WANG Wenxi TIAN Jian DENG Guanghui SU Suizheng QI State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and TechnologyXi’an Jiaotong UniversityXi’an 710049China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

A comparative computational fluid dynamics(CFD)study was conducted on the three different types of pressurized water reactor(PWR)upper plenum,named TYPE 1(support columns(SCs)and control rod guide tubes(CRGTs)with two large windows),TYPE 2(SCs and CRGTs without windows),and TYPE 3(two parallel perforated barrel shells and CRGTs).First,three types of upper plenum geometry information were collected,simplified,and adopted into the BORA facility,which is a 1/5 scale system of the four-loop PWR ***,the geometry,including the upper half core,upper plenum region,and hot legs,was built using the Salome *** that,an unsteady calculation to simulate the reactor balance operation at hot full power scenario was ***,the differences of flowrate distribution at the core outlet and temperature distribution and transverse velocity inside the hot legs with different upper plenum internals were *** results suggest that TYPE 1 upper plenum internals cause the largest flowrate difference at the core outlet while TYPE 3 leads to the most even distributed *** distribution and evolution pattern of the tangential velocity inside hot legs is highly dependent on the upper plenum *** counter-rotating swirls exist inside the TYPE 1 hot leg and only one swirl revolving around the hog leg axis exist inside the TYPE 2 hot *** TYPE 3,two swirls like that of TYPE 1 rotating around the hot leg axis significantly increase the temperature homogenization *** research provides meaningful guidelines for the future optimization and design of advanced PWR upper plenum internal structures.

关键词： pressurized water reactor(PWR) upper plenum internal structures temperature distribution computational fluid dynamics(CFD)

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Study on the Optical Properties, Crystal Growth and Photocatalytic Activity of Ni-doped TiO2 Nanoparticles 18

Study on the Optical Properties, Crystal Growth and Photocat...

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18th World Hydrogen Energy Conference, WHEC 2010

作者： Guo, Penghui Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University China

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Characterization of soot based on variable laser-induced spectroscopy

Characterization of soot based on variable laser-induced spe...

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Digital Holography and Three-Dimensional Imaging, DH 2016

作者： Chen, Jun Zhang, Yanfeng Yan, Huinan Su, Mingxu School of Energy and Power Engineering Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering China

The soot raise great environmental and health problems. Conventional methods don ' t have such low measurement limits. So in this paper soot's component and size information will be studied in theory and exper... 详细信息

ISBN: (纸本)9781943580156

关键词： Soot

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Performance Analysis of Low GWP Refrigerants R1234yf and R448A in a Small High and Low-temperature Test Equipment

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Recent Patents on Mechanical engineering 2022年第3期15卷 277-284页

作者： Liqiang, Zhou Zhang, Hua Zilong, Wang Wenjing, Gao School of Energy and Power University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093 China

Aim: The article presents an analysis of the feasibility of R1234yf and R448A, two new low GWP refrigerants, as alternatives to R404A in the refrigeration system of small high and low-temperature test equipment. Methods: The physical properties of R448A and R404A are similar. Compared with R404A, the GWP of R1234yf and R448A reduced by 99.9% and 67.7%, respectively. The analysis is based on an experimental comparison of R404A with R448A and R1234yf, comparing the compressor discharge tempera-ture, COP, cooling capacity, and the cooling rate of three refrigeration systems at different ambient temperatures. Results: The experimental results show that the cooling capacity of R448A is better than R404A at a higher condensing temperature. Conclusion: When the charging volume is 230g, and the ambient temperature is 25°C, the COP of the R448A system is increased by about 24.63% compared with the R404A system. © 2022 Bentham Science Publishers.

关键词： Refrigerants

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Gas emission source term estimation with 1-step nonlinear partial swarm optimization-Tikhonov regularization hybrid method

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Chinese Journal of Chemical engineering 2018年第2期26卷 356-363页

作者： Denglong Ma Wei Tan Zaoxiao Zhang Jun Hu School of Food Equipment Engineering and Science Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University School of Chemical Engineering and Technology Xi'an Jiaotong University School of Chemical Engineering Northwest University

Source term identification is very important for the contaminant gas emission event. Thus, it is necessary to study the source parameter estimation method with high computation efficiency, high estimation accuracy and reasonable confidence interval. Tikhonov regularization method is a potential good tool to identify the source parameters. However, it is invalid for nonlinear inverse problem like gas emission process. 2-step nonlinear and linear PSO （partial swarm optimization）-Tikhonov regularization method proposed previously have estimated the emission source parameters successfully. But there are still some problems in computation efficiency and confidence interval. Hence, a new 1-step nonlinear method combined Tikhonov regularizafion and PSO algorithm with nonlinear forward dispersion model was proposed. First, the method was tested with simulation and experiment cases. The test results showed that 1-step nonlinear hybrid method is able to estimate multiple source parameters with reasonable confidence interval. Then, the estimation performances of different methods were compared with different cases. The estimation values with 1-step nonlinear method were close to that with 2-step nonlinear and linear PSO-Tikhonov regularization method, 1-step nonlinear method even performs better than other two methods in some cases, especially for source strength and downwind distance estimation. Compared with 2-step nonlinear method, 1-step method has higher computation efficiency. On the other hand, the confidence intervals with the method proposed in this paper seem more reasonable than that with other two methods. Finally, single PSO algorithm was compared with 1-step nonlinear PSO-Tikhonov hybrid regularization method. The results showed that the skill scores of 1-step nonlinear hybrid method to estimate source parameters were close to that of single PSO method and even better in some cases. One more important property of 1-step nonlinear PSO-Tikhonov regularization metho

关键词： Parameter estimation Parameter regularization method Source identification Inverse problem

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Numerical analysis on heat transfer enhancement by longitudinal vortex based on field synergy principle

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中国高等学校学术文摘·能源与动力工程 2007年第3期1卷 365-369页

作者： WU Junmei TAO Wenquan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China School of Environment and Chemical Engineering Xi'an Polytechnic UniversityXi'an 710048China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Three-dimensional numerical simulation results are presented for a fin-and-tube heat transfer surface with vortex *** effects of the Reynolds number (from 800 to 2 000) and the attack angle (30° and 45°) of a delta winglet vortex generator are *** numerical results are analyzed on the basis of the field synergy principle to explain the inherent mechanism of heat transfer enhancement by longitudinal *** secondary flow generated by the vortex generators causes the reduction of the intersection angle between the velocity and fluid temperature *** addition,the computational evaluations indicate that the heat transfer enhancement of delta winglet pairs for an aligned tube bank fin-and-tube surface is more significant than that for a staggered tube bank fin-and-tube *** heat transfer enhancement of the delta winglet pairs with an attack angle of 45° is larger than that with an angle of 30°.The delta winglet pair with an attack angle of 45° leads to an increase in pressure drop,while the delta winglet pair with the 30°angle results in a slight *** heat transfer enhancement under identical pumping power condition for the attack angle of 30° is larger than that for the attack angle of 45°either for staggered or for aligned tube bank arrangement.

关键词： longitudinal vortex heat transfer enhancement field synergy principle

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Influence of transient thermal response of solid wall on bubble dynamics in pool boiling

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Journal of Computational multiphase flows 2014年第3期6卷 313-327页

作者： Zhang, Liang Li, Zhen-Dong Li, Kai Li, Hui-Xiong Zhao, Jian-Fu Beijing100190 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi710049 China Beijing102209 China

Numerical simulation of single bubble pool boiling process including transient thermal response of solid wall is performed using the ghost fluid method and the level set method for the sharp interface representation. The results show that non-physical initial condition in the numerical simulation deeply affects the process of bubble growth, and then multi-cycle simulation is necessary to eliminate its influence. It is shown by the present results that two nucleate criteria, i.e. constant waiting time and constant nucleate superheat, for determining the appearance time for the subsequent bubble lead to the same quasi-steady process of bubble growth if they are matched with each other. A periodically expanding and receding thermal "hollow" can be observed inside solid wall underneath the growing bubble. The recovery of the temperature on the nucleate site and the thermal boundary layer near the heating surface is influenced by transient heat conduction inside solid wall, which can affect evidently bubble thermal dynamics and heat transfer.

关键词： Numerical methods

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