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Research on the Hydrodynamic Characteristics and Metal Temperature Distribution in Spiral tube Water Wall of an Ultra Supercritical Boiler

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AIP Conference Proceedings 2010年第1期1207卷 199-204页

作者： Weijing Zhang Dong Yang Jie Pan Xu Zhou State Key Lab of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

On the basis of a 350 MW supercritical pressure OTSC boiler, established the mathematical model for the circulation loop flow and grid pressure in a complex flow network system, and an iteration method was used to solve the nonlinear equations. The water wall flow distribution and temperature profile of the boiler were computed. The results show that the flow difference and heat difference are small in spiral tube water wall at BMCR, 75%BMCR load and 30%BMCR load. The metal temperatures are all in the range of allowable range, and the operation of boil is safe and reliable.

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Experimental investigation on the conversion of nitrogenous gas products during coal pyrolysis

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Journal of Fuel Chemistry and Technology 2008年第2期36卷 134-138页

作者： Hai-feng LIU Yin-he LIU Yan-hua LIU De-fu CHE State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

The conversion of nitrogenous gas products during coal pyrolysis is investigated in a drop tube reactor. Four raw coals and two demineralized coals have been used for pyrolysis at 500°C, 700°C, 900°C and 1100°C. The results indicate that the yields of N 2 and NO precursors, such as HCN and NH 3 , increase with increasing temperature. Coal type has significant effect on the yield of nitrogenous gas products. For lower rank coal, the conversion of fuel nitrogen is higher. Majority of fuel nitrogen in high rank coals is built into condensed aromatic structures to form Char-N. The mineral matters in coal can promote the conversion of fuel nitrogen to N 2 , but they can also suppress the conversion of fuel nitrogen to HCN and NH 3 .

关键词： coal pyrolysis HCN NH 3 N 2

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An Adaptive VOF Method on Unstructured Grid

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AIP Conference Proceedings 2011年第1期1376卷 642-644页

作者： L. L. Wu M. Huang B. Chen State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

In order to improve the accuracy of interface capturing and keeping the computational efficiency, an adaptive VOF method on unstructured grid is proposed in this paper. The volume fraction in each cell is regarded as the criterion to locally refine the interface cell. With the movement of interface, new interface cells (0 ≤ f ≤ 1) are subdivided into child cells, while those child cells that no longer contain interface will be merged back into the original parent cell. In order to avoid the complicated redistribution of volume fraction during the subdivision and amalgamation procedure, a predictor‐corrector algorithm is proposed to implement the subdivision and amalgamation procedures only in empty or full cell ( f = 0 or 1). Thus volume fraction in the new cell can take the value from the original cell directly, and the interpolation of the interface is avoided. The advantage of this method is that the re‐generation of the whole grid system is not necessary, so its implementation is very efficient. Moreover, an advection flow test of a hollow square was performed, and the relative shape error of the result obtained by adaptive mesh is smaller than those by non‐refined grid, which verifies the validation of our method.

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An Experimental Study of on-line Measurement of Water Fraction in Gas-Oil-Water Three-Phase flow

An Experimental Study of on-line Measurement of Water Fracti...

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The 7th International Symposium on Measurement Techniques for multiphase flows

作者： K.Chen L.J.Guo J.Ye State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

Gas-oil-water two- or three-phase flow is widely encountered in industry,such as petroleum chemical industry,bio-chemicals,food chemicals,and mineral engineering and energy *** kinds of on-line measurement technique,which are double-ring conductance sensor and double-helical capacitance sensor,for water fraction in oil-water two-phase flow and gas-oil-water three-phase flow were developed in this *** calibration results shows that the responses of the two sensors are good enough as the variation of water *** on the other hand,it is possible that the oil and the gas regard as one phase in gas-oil-water three-phase flow by using double-helical capacitance sensor,and the ratio between water and gas has no effect with the output *** range of water fraction which can be measured becomes bigger and bigger because of the using of new *** the capacitance sensor is better enough to measure water fraction in the three phases *** dynamic experiment,because of phase inversion phenomenon between oil and water,the conductance sensor outputs poorly,however the capacitance sensor performs somewhat *** reason for the error using capacitance sensor is the edge effect of the *** experiment results show that the edge effect of the double-helical capacitance sensor causes that the output is smaller so that the measuring water fraction is a litter larger than the actual *** when the variation of water fraction is above 10%,the edge effect of capacitance sensor can be almost *** the contrary,when the variation of water fraction is below 10%,the edge effect is so lager than the results above that it cannot be ***,the double-helical capacitance probe is more suitable for measuring water fraction in slug flow and oil-water emulsion,in which the results agree better with static calibration than that in bubble flow.

关键词： Double-ring conductance sensor Double-helical capacitance sensor Gas-oil-water three-phase flow Water fraction Measurement technique

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Experimental study on heat transfer to supercritical CO2 flowing in vertical upward tube at medium mass flux

Experimental study on heat transfer to supercritical CO2 flo...

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ASME 2017 Nuclear Forum, NUCLRF 2017, collocated with the ASME 2017 power Conference Joint with ICOPE 2017, the ASME 2017 11th International Conference on Energy Sustainability, and the ASME 2017 15th International Conference on Fuel Cell Science, engineering and Technology

作者： Zhang, Qian Li, Huixiong Kong, Xiangfei Zhang, Jun Lei, Xianliang Zhang, Weiqiang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi'anShaanxi China North Carolina State University United States Burlington Laboratory 3144 North Carolina State University RaleighNC27607 United States

ISBN: (纸本)9780791840597

An experimental study was performed on heat transfer characteristics of supercritical pressure CO2 (SC-CO2) flowing at medium mass flux conditions in a vertically-upward tube of 16 mm inner diameter at the Heat Transfer and flow test loop of Supercritical CO2 (HTF-SCO2) in Xi’an Jiaotong University. Experimental parameters included the pressure ranging from 7.5 to10.5 MPa, the mass flux of 400-600 kg/m2s, and the heat flux of 20-100 kW/m2. Based on the experimental data, effects of mass flux, heat flux and operation pressure on heat transfer characteristics of SC-CO2 were thoroughly discussed. With the decrease of mass flux and increase of heat flux, heat transfer characteristics of SC-CO2 becomes worse and worse. The wall temperature rises to high levels with the occurrence of a wall temperature peak and the wall temperature peak also rises remarkably with the decrease in mass flux and increase in heat flux. Especially, effect of pressures on the heat transfer of SC-CO2 was found to be quite different from that previously reported in literature. When the heat flux is low (such as 30 kW/m2), the HTD was diminished with the increase in pressures, but when the heat flux is up to 50 kW/m2, the HTD is surprisingly intensified by the increase of pressure. The buoyancy effect was considered to explain this distinct influence of pressure on the heat transfer of SC-CO2 by employed a non-dimensional parameter Bu. With the increase of pressure, buoyancy effect was diminished owing to the decrease of density difference between fluids near the wall and the center. When heat flux was lower, the Bu was located between 5×10-6 and 10-4, where buoyancy effect impaired heat transfer, so the heat transfer coefficient increased by rising pressure. But when heat flux was larger, the Bu was above 10-4, where buoyancy effect began to enhance heat transfer, as a result, the heat transfer coefficient was reduced by weakened buoyancy effect because of the increase of pressure (CSPE). Copyrig

关键词： Heat flux

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Study on the Radiation Distribution in A Fluidized Tubular Reactor for Heterogeneous Photocatalytic Hydrogen Production

Study on the Radiation Distribution in A Fluidized Tubular R...

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2011 International Conference of Environmental Science and engineering（ICESE 2011）

作者： Zhao Liang Fan Liangliang Jing Dengwei Liu Wenxu Cao Fei Zhu Xule Yang Junyin Zhang Hailong State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

Radiation distribution study is of importance for the design and the optimization of fluidized photocatalytic tubular reactor which has been developed for photocatalytic hydrogen production under direct solar light. In the present study, the radiation distribution in such reactor was successfully simulated by adopting Monte Carlo method and the six-flux radiation absorption-scattering models. Both the incident angles of light around the reactor and the concentration distribution of photocatalyst were taken into account. Our analysis indicates that the angles and the intensity of the incident rays significantly affect the radiation distribution. Moreover, it was also found that the equilibrium radiation distribution has a close relationship with the density distribution of the photocatalysts. The simulated results are expected to be helpful for obtaining the optimal operating parameters for solar photocatalytic hydrogen production.

关键词： Radiation distribution,Fluidized tubular reactor,Nanometer catalyst Compound parabolic concentrators

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A New Measuring Method of Oil‐water‐gas Three Phase flowrate by Using of Heat Transfer and Fluid Dynamics

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AIP Conference Proceedings 2007年第1期914卷 221-225页

作者： Hongwei Liao Siyi Zhou Lei Liu Fangde Zhou Key State Laboratory of Multiphase Flow In Power engineering Xian Jiaotong University Xian. China

It is so difficult to measure individual flowrates of oil‐water‐gas three phase on‐line that very few real three phase flowmeters have been developed in the world. This paper presents a new measuring method of oil‐water‐gas three phase flowrate by using of heat transfer and fluid dynamics. A cylindrical cyclone is used to separating the most of natural gas from oil‐water‐gas three phase mixture. A flow mixer is used to homogenize oil and gas flow in a short distance for measurement of bulk flow velocity. A venture‐tube is used to measure overall flowrate of three phase mixture. An inverse‐U tube is used to measure gas fraction. The heat transfer way is used to measure water fraction. No radiation method is used. So this kind of flowmeter is much more safety, and has much more accuracy. Many room and field experiments have been done. The test results done by the Test Institute of Petroleum Industry of Daqing Oil Field Construction & Design Research Institute were quite well. This kind of three phase flowmeter has been widely used in many oil fields.

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Mathematical model and numerical simulation of helical baffles heat exchanger

Mathematical model and numerical simulation of helical baffl...

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作者： Shen, Renjie Feng, Xiao Gao, Xiaodong Department of Chemical Engineering State Key Laboratory of Multi-Phase Flow in Power Engineering Xi'An Jiaotong University Xi'an China

With the theory of the Reynolds stress model applied, a mathematical model of the flow and heat transfer of the helical baffles heat exchanger is established. The commercial software FLUENT is used to simulate the influence of helical baffles on heat transfer capability and flow resistance of helical baffle heat exchangers by unstructured grid. The numerical simulation results at the 35° helix inclination angle are compared with those of experiment. © 2004 by Begell House, Inc.

关键词： Heat exchangers

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Synthesis of tert -amyl Ethyl Ether for Gasoline Additive

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Energy Procedia 2015年 75卷 3265-3270页

作者： Zhao Lei Hang Zhang Jing-Jun Liu Bo-Lun Yang Department of Chemical Engineering State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

A series of experiments were carried out in a batch reactor at the temperature range of 313-343 K to study the synthesis of tert -amyl ethyl ether from ethanol (EtOH) and 2-methyl-1-butene (2M1B) catalyzed by the NKC-9 ion-exchange resin. The suitable reaction pressure was obtained by using the method of the Gibbs free energy minimization. The activity coefficients of each component were accurately calculated using the Wilson method, then, the equilibrium constants was obtained. The effect of catalyst size, stirring rate, temperature and EtOH/2M1B molar ratio was investigated at the chosen pressure, respectively. A kinetic model which considered the variation of each component volume was established. The method of nonlinear least square combined with genetic algorithm (NLS-GA) was proposed to estimate the kinetic constant in the forward direction. Results indicated that simulated kinetics results were agreed well with the experimental data.

关键词： Batch reaction Gibbs free energy Kinetics Aspen Plus

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Thermodynamic Analysis on a Pre-dried Lignite-fired power System: Comparison on Energy Supply Systems for Dryer

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Energy Procedia 2014年 61卷 1424-1427页

作者： Ming Liu Junjie Yan Jinshi Wang Daotong Chong Jiping Liu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

Pre-drying is a potential way to improve the electric generation efficiency of lignite-fired power plant, and steam is a main kind of drying heat source. In conventional pre-dried lignite-fired power system, the steam extraction of regenerative system is led to the dryer directly. The steam extraction must be used by the dryer after throttling, if the energy mismatch exists between the supply of steam extraction and the need of dryer. Two systems of energy supply for the dryer, that the energy of the steam extraction is supplied to the dryer via compressor or ejector, were proposed in this paper to further increase the energy utilization efficiency. These systems were thermodynamic analyzed, and the electric generation efficiencies of these systems were compared. The energy saving boundary was gotten.

关键词： Thermodynamics Lignite pre-drying Compressor Ejector

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