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Experimental and modeling study of the effects of equivalence ratio on the benzene formation chemistry of one-dimensional laminar premixed n-heptane flames

Experimental and modeling study of the effects of equivalenc...

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8th International Conference on Modeling and Diagnostics for Advanced Engine Systems, COMODIA 2012

作者： Chen, Gen Yu, Wu Fu, Jin Huang, Zuohua Yang, Jiuzhong Wang, Zhandong Qi, Fei State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei Anhui 230029 China

In order to gain a better understanding of the soot formation mechanism involved in the combustion process of hydrocarbon fuels, laminar premixed n-heptane flames with different equivalence ratios (1.20, 1.60 and 1.80) are studied by using synchrotron photoionization and molecular-beam mass spectrometry (PI-MBMS) techniques at low pressure(30Torr). To isolate the influence from flame temperature, the composition of unburned mixtures is adjusted such that the temperature profiles are approximately equivalent. Mole fraction profiles of major and intermediate species were derived and compared among different flames. Parallel modeling study based on a modified mechanism is conducted. The predicted mole fraction profiles of concerned species agree reasonably well with experimental measurements. The results show that, as equivalence ratio increases, the equilibrium mole fractions of H2O and CO2 decrease while those of H2 and CO increase, and the concentrations of benzene and toluene and those of C2-C 5 hydrocarbon intermediates increase apparently. The reaction flux analysis indicates that the self-recombination of propargyl radical (C 3H3) and the cross reaction between C3H 3 and allyl radical (a-C3H5) are the dominant pathway leading from small aliphatics to C6H6. The consumption of C6H6 is primarily resulted from the attack by OH and H radicals. The larger amount of C6H6 formed in richer flames should be attributed mainly to the higher concentrations of benzene precursors. In addition, the weakening influence of the OH-attack and O-attack reaction tends to slow down the consumption of C6H 6, which also contributes to the higher C6H6 concentration in the richer flames. Copyright © 2012 by the Japan Society of Mechanical Engineers.

关键词： Benzene

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Irreversibility Analysis of a Recuperative Heater during Undergoing the flowrate Impulsive Disturbance Transient Processes

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Energy Procedia 2019年 158卷 5311-5316页

作者： Chaoyang Wang Yongliang Zhao Zhu Wang Ming Liu Junjie Yan State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

The recuperative heater is widely used in the industrial production processes, and the irreversibility analysis on the heater during transients is scarce but necessary. Numerical method was adopted to model the recuperative heat exchanger to exhibit its dynamic behaviors during transient processes. The difference between the transient and stationary irreversibility can be called additional irreversibility. In this paper, the dynamic behaviors of the recuperative heater during transients are presented. With these thermal parameters, the irreversibility of a recuperative heater during hot and cold fluid flow rates impulsive disturbance transient processes was calculated and analyzed in detail. The calculation results show that: compared with steady-state corresponding value, the real-time irreversibility rate of the heater during transients is different. The total additional irreversibility values with impulsive disturbance in hot and cold fluid flow rates are obtained separately.

关键词： Recuperative heaters Irreversibility analysis Dynamic modeling Transisent processes

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

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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.

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Experimental Study on the flow Characteristics of a Plate with a Mechanically Choked Orifice

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Fluid Dynamics & Materials Processing 2021年第1期17卷 97-107页

作者： Ming Liu Xingkai Zhang Dong Wang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China Petroleum Engineering Technology Research Institute of Shengli Oilfield Company SINOPECDongying257000China Shandong Key Laboratory of Heavy Oil Production Technology Shengli Oilfield CompanySINOPECDongying257000China Petroleum Engineering College Yangtze UniversityWuhan430100China

The mechanically choked orifice plate (MCOP) is a new type of device for flow control by which choking conditionsfor incompressible fluids can be obtained with relatively small pressure losses. Given the lack of relevant results anddata in the literature, in the present study, we concentrate on the experimental determination of the flow coefficientfor the annular orifice, the pressure distribution in the MCOP, and the characteristics of the choked flow itself. Asconfirmed by the experimental results, the Reynolds number, the orifice plate thickness, the plug taper, and theeccentricity have an obvious influence on the aforementioned flow coefficient. The pressure drop in the MCOPis mainly generated near the orifice plate, and the pressure upstream of the orifice plate is slightly reduced in theflow direction, while the pressure downstream of the orifice plate displays a recovery trend. The choked flow rateof the MCOP can be adjusted by replacing the spring with a maximum flow control deviation of 4.91%.

关键词： Mechanical choked orifice plate flow control flow coefficient flow characteristics

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1‐Dodecane‐sulfonic‐acid‐sodium‐salt(LAS) assisted hydrothermal synthesis of CdxZn1−xS solid solution as efficient photocatalysts under visible light irradiation

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AIP Conference Proceedings 2010年第1期1207卷 1048-1052页

作者： B. Jia L. J. Guo aState Key Laboratory of Multiphase Flow in power Engineering Xi’an Jiaotong University China bState Key Laboratory of Multiphase Flow in power Engineering Xi’an Jiaotong University China

With anionic surfactant LAS assisted, series of zinc cadmium sulfide semiconductor photocatalysts were synthesized by hydrothermal method. These products were characterized by X‐ray diffraction (XRD), UV‐Vis absorption spectra (UV‐Vis) and scanning electron microscopy (FESEM). The photocatalytic activities of as‐prepared samples were evaluated by photocatalytic hydrogen production from water under visible‐light irradiation. The best synthesis parameters are: Composition 0.9:0.1 (Cd:Zn molar ratio), Temperature 160 °C, Hydrothermal Time 48 Hour, LAS Concentration 1.7 mmol/L, the maximum visible‐light‐catalytic hydrogen production rate is 161.25 μmol/h (λ>430 nm) which is higher than those of by coprecipitation method. The experiment results indicate that surfactant assisted hydrothermal method is an effective way to get highly active CdZnS solid solution photocatalyst.

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Optimal design of guide vane inthe cyclone vortex finder based on orthogonal analysis 12

Optimal design of guide vane inthe cyclone vortex finder bas...

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12th International Conference on Fluidized Bed Technology, CFB 2017

作者： Huang, Zhong Liu, Ming Liu, Guanjie Wang, Fengyang Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering Xi 'an Jiaotong University Xi 'an710049 China State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing100084 China China Huaneng Clean Energy Research Institute Beiijing102209 China

A new structure of installing guide vane inside eccentric vortex finder of cyclone was proposed. Five parameters including eccentric ratio e, blade number Z, hub inlet installing angle p, middle coefficient of hub installing angle k, shroud inlet installing angle increment Ap were selected to design an orthogonal table of five elements and four levels. Based on RNG k-e model, separation efficiencies of the conventional cyclone and 16 cyclones installing guide vanes inside vortex finder were calculated. By means of orthogonal analysis, the influence of each element has been ranked, and the optimal level of each element has been combined as the optimal structure. The simulation result indicated that the separation efficiency of the optimal structure has increased up to 7.04% while the pressure drop decreased no more than 12.5%. The flow field analysis showed the velocity in the inner vortex of cyclone was lower, while it was higher in the outer vortex, which is of great help for particle separation.

关键词： Vortex flow

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Study of a PEMFC performance based on a novel current distribution measurement method

Study of a PEMFC performance based on a novel current distri...

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16th World Hydrogen Energy Conference 2006, WHEC 2006

作者： Zhang, Guangsheng Sun, Hong Guo, Liejin Shang, Dehua Liu, Hongtan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 China Department of Mechanical Engineering University of Miami Coral Gables FL 33124 United States

ISBN: (纸本)9781622765409

With the novel and simple current distribution measurement gasket developed by MPFL, the performance of a single PEM fuel cell with serpentine flow field was investigated without modifying any of its components. Inhomogeneous current distributions were demonstrated clearly by the measurement results. Current distribution at different cell operating parameters, including reactant gas flow rate, reactant gas humidification temperature and cell operating temperature, were measured and the effects of such parameters were analyzed. Reactant gas flow rate exert effects on current distribution by influencing the reactant concentration distribution, while the critical effects of gas humidification and cell temperature is caused by their significant influence on water balance and water distribution in PEM fuel cell. To fully understand the combined effects of such factors, simultaneous measurement of current distribution, reactant distribution, temperature distribution and humidification distribution is necessary and will be helpful.

关键词： flow of gases

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

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

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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

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Deformation Analysis and Prediction of Pneumatic Probe Based on Fluid-structure Interaction

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International Journal of Fluid Machinery and Systems 2023年第1期16卷 1-13页

作者： Fan, Yang Dexin, Qiu Xinwei, Zhao Qingyi, Sai Xiaoshu, Cai School of Energy and Power Engineering University of Shanghai for Science and Technology No. 516 Jungong Road Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Sh anghai for Science and Technology No. 516 Jungong Road Shanghai200093 China

As an essential tool for measuring flow field, pneumatic probes have gained a wide range of applications. In order to obtain the flow field parameters accurately, it is also crucial to study the deformation of the pneumatic probe structure in flow field. In this paper, the deformation of the conical probe is numerically simulated under the condition of steady incoming flow in the transonic flow field. The fluid-structure interaction and modal analysis methods are used to obtain the deformation and vibration frequency of the probe. The results show that the vibration of the probe is underdamped under the action of two-way fluid-structure interaction, and the total deformation decays exponentially, and the total deformation after stabilization is the same as the result of one-way fluid-structure interaction. For the same material probe, the total deformation changes with time in the same dimensionless expression, and the vibration frequency as well as damping factor do not change due to the variation of flow field. The accuracy of the dimensionless expressions was verified by different incoming flow conditions and the probe material. For the cases studied in this paper, the maximum total deformation, vibration frequency and damping factor of the probe in the flow field can be obtained by using one-way fluid-structure interaction, modal analysis and two-way fluid-structure interaction with a small number of cycles, respectively, so that the total deformation of the probe in the flow field can be predicted over time. The method obtained in this paper can significantly reduce the calculation time for obtaining the probe deformation data in the flow field and improve the work efficiency, which can provide a reference for the design, calibration and application of probes in engineering applications. © 2023, Turbomachinery Society of Japan. All rights reserved.

关键词： Modal analysis

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Laminar burning velocity of gasoline and gasoline surrogates under various pressures and temperatures 12

Laminar burning velocity of gasoline and gasoline surrogates...

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12th Asia-Pacific Conference on Combustion, ASPACC 2019

作者： Hu, Erjiang Xu, Zhaohua Gao, Zhenhua Huang, Zuohua Stake Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University No.28 Xianning West Road Shaan Xi710049 China

The outwardly propagating spherical flame method was used to measure the laminar burning velocity of a commercial gasoline fuel having RON of 92 and gasoline surrogate. Measurements were conducted at the equivalence ratio of 0.8 to 1.5, initial temperatures of 358 K, 403 K, and 448 K and initial pressures of 1 atm, 2 atm and 5atm in a constant volume bomb. The surrogate of primary reference fuel (PRF-92, 92% iso-octane + 8% n-heptane) and toluene reference fuel (TRF-92, 16.69% iso-octane + 22.65% n-heptane + 60.66% toluene) were proposed to match the laminar burning velocity of gasoline (CNPC 92#). It could be found that the TRF-92 was able to successfully reproduce the laminar burning velocity of the gasoline under various experimental conditions. © Asia-Pacific Conference on Combustion, ASPACC *** right reserved.

关键词： Gasoline

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