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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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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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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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Temporal and spatial non-uniformity of surface heat transfer during r404a spray cooling in laser surgery 13

Temporal and spatial non-uniformity of surface heat transfer...

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13th International Conference on Liquid Atomization and Spray Systems, ICLASS 2015

作者： Wang, R. Zhou, Z.F. Chen, B. Bai, F.L. Wang, G.X. State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

Cryogen spray cooling has been applied to protect epidermis from thermal damage in laser dermatology. However, present cryogen R134a shows insufficient cooling capacity on minimizing the laser energy absorption by the melanin in darkly pigmented human skins. With lower boiling point, R404A has potential to improve the cooling capacity. This paper presents an experimental study on the temporal and spatial variation in surface temperature and heat flux during spray cooling using R404A by a straight tube nozzle with expansion chamber, which significantly improves the atomization effect. The experimental results indicate that the temporal and spatial conditions strongly influence the uniformity of surface heat transfer. There exists a sub-region of uniform cooling with radius of 2 mm around spray center with high transient heat flux above 400 kW/m2, which is conducive for physicians to control the therapy area precisely with enhanced laser energy. © 2015 International Conference on Liquid Atomization and Spray Systems. All rights reserved.

关键词： Laser surgery

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Delaying Modified QUICK Scheme and its Application in Slug flow

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Journal of Thermal Science 2001年第2期10卷 139-143页

作者： LU Yuan-Wei HE An-Ding WANG Yue-She ZHOU Fang-De The National Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

The National laboratory of multiphase flow in power engineering Xi' an Jiaotong University, Xi' an 710049, China Abstract:Calculations of several classic questions in numerical heat transfer with delaying modified QUICK scheme show good agreement with benchrnark. Combining volume of fluid model with the well known SIMPLEC method. the reasonanble Tgylor bubble shape has ben obtained by using delaying modified QUICK scheme and donor acceptor scheme of interfacial advection respectively. At the same the the stream field and the liquid film thickness around the Taylor bubble have been well figured out

关键词： slug flow Taylor-bubbles QUICK scheme SIMPLEC method.

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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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Development of a three-dimensional method for thermal-hydraulics/neutronics coupling analysis and its application on CFETR helium-cooled solid breeder blanket

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International Journal of Advanced Nuclear Reactor Design and Technology 2021年 3卷 154-165页

作者： Lian, Qiang Tian, Wenxi Qiu, Suizheng Su, G.H. Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Blankets are of practical importance in the fusion reactor due to their main functions for engineering application. As the fusion power designed for the Chinese Fusion engineering Test Reactor (CFETR) is increased from 200 MW to 1.5 GW during its phase II operation, more challenges are issued for blankets from the points of view of thermal-hydraulics, neutronics, mechanics, and safety. In this paper, the Coupling Analysis of Thermal-hydraulics and Neutronics Interface Code (CATNIC) was developed using the user-defined function (UDF) in the CFD software FLUENT. The explicit coupling scheme based on cell-to-cell mapping approach was adopted to transfer data between neutronics calculation and thermal-hydraulics simulation. Three-dimensional thermal-hydraulic model and neutronics model were established using Fluent and MCNP4C, respectively. The helium-cooled solid breeder (HCSB) blanket of CFETR was simplified as a slice model to reduce the computing resources. With the slice model of CFETR HCSB blanket, the coupling analysis was carried out using the developed CATNIC. The calculation results from coupling and non-coupling analyses were compared to verify the feasibility of the coupling method in this study. As the helium coolant was considered as the transparent medium for neutron, the thermal-hydraulic and neutronics analyses were both converged after two iterations. However, using the developed coupling method in this study, the detailed change of tritium production ratio (TPR) and nuclear heat deposition in different parts of the blanket was revealed, which could provide important guidance for the design of the distribution for both coolant and purge gas. © 2021 Xi'an Jiaotong University

关键词： Coolants

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Mitigating check valve slamming and subsequentwater hammer events for PPFS using MOC

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Nuclear Science and Techniques 2009年第2期20卷 118-123页

作者： TIAN Wenxi SU Guanghui WANG Gaopeng QIU Suizheng XIAO Zejun State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and TechnologyXi＇an Jiaotong University Xi＇an 710049 China National Key Laboratory of Bubble Physics ＆ Natural Circulation Nuclear Power Institute of China Chengdu 610041 China

The method of characteristic(MOC) was adopted to analyze the check valve-induced water hammer behaviors for a Parallel Pumps Feedwater System(PPFS) during the alternate startup *** motion of check valve disc was simulated using inertial valve *** parameters including the pressure oscillation,local flow velocity and slamming of the check valve disc *** been *** results showed that severe slamming between the valve disc and valve seat occurred during the alternate startup of parallel *** induced maximum pressure vibration amplitude is up to 5.0 *** scheme of appending a damping torque to slow down the check valve closing speed was also performed to mitigate of water *** has been numerically approved to be an effective approach.

关键词：止回阀建设部事件水锤泵给水系统启动过程压力振动瞬态参数

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