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学者姓名：王景甫
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Abstract ：
Green ammonia has become an increasingly popular fuel in recent years because of its combustion process without carbon oxide release. Adding ammonia to methane fuel for co-combustion has become one of the important research topics in the current combustion field. In the present study, the CH4/NH3/Air counterflow diffusion flame was taken as the research object, and Chemkin-2019 R3 software was used to explore and analyze the flame extinction limit and chemical kinetics characteristics under different ammonia mixing ratios, initial pressures, and air preheating temperatures. It was obtained that the flame extinction stretch rate was decreased by increasing the NH3 mole fraction in the CH4/NH3 mixed fuel. The increase in pressure or air preheating temperature would accelerate the chemical reaction rate of each component in the combustion process, increase the flame extinction limit, and counteract the "stretching effect" of the flame, thus restraining the flame extinguishing phenomenon. The results of a path analysis show that the formation and consumption of OH had an important influence on flame extinction in the chain reaction. The net reaction rate of OH increases with increasing the initial pressure or air preheating temperature, which leads to an increase in flame intensity, combustion stability, and the extinction limit. Furthermore, the function curve between the reaction influences the RIF factor and the stretch rate of the first-to-ten reactions, affected by the heat release of flame combustion, was drawn and quantitatively analyzed. Eventually, a sensitivity analysis of the flame under different working conditions was completed, which found that promoting the forward reaction R39 H + O-2<=>O + OH also promotes the positive combustion as a whole when the flame was near extinction. The sensitivity coefficient of R39 in the CH4/NH3/Air flame increases with the growing initial pressure. The increasing air preheating temperature was capable of switching the reaction of R248 NH2 + OH<=>NH + H2O in the CH4/NH3/Air flame from an inhibiting reaction to a promoting reaction, while decreasing the sensitivity coefficient of inhibiting the forward reaction R10 O + CH3<=>H + CH2O, R88 OH + HO2<=>O-2 + H2O, and R271 H + NO + M<=>HNO + M. Thus, the inhibition effect of flame extinction was weakened, and the positive progress of combustion was promoted.
Keyword ：
chemical kinetic characteristics chemical kinetic characteristics extinction limits extinction limits methane/ammonia mixed fuel methane/ammonia mixed fuel counterflow diffusion flame counterflow diffusion flame
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| GB/T 7714 | Chen, Ying , Wang, Jingfu , Zhang, Jian et al. Numerical Study on Chemical Kinetic Characteristics of Counterflow Diffusion Flame Extinction of Methane/Ammonia/Air Flame under High Pressure or Air Preheating Temperature [J]. | MOLECULES , 2024 , 29 (15) . |
| MLA | Chen, Ying et al. "Numerical Study on Chemical Kinetic Characteristics of Counterflow Diffusion Flame Extinction of Methane/Ammonia/Air Flame under High Pressure or Air Preheating Temperature" . | MOLECULES 29 . 15 (2024) . |
| APA | Chen, Ying , Wang, Jingfu , Zhang, Jian , Li, Yi . Numerical Study on Chemical Kinetic Characteristics of Counterflow Diffusion Flame Extinction of Methane/Ammonia/Air Flame under High Pressure or Air Preheating Temperature . | MOLECULES , 2024 , 29 (15) . |
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Abstract ：
Extinction limits and flame microstructures of CH4 versus air (N-2/O-2) counterflow diffusion flames with additional CO2 to oxidizer stream under various pressure conditions were numerically investigated by a proposed decoupled strategy. The chemical and thermal effects of CO2 addition were isolated from the synergistic effect on extinction limits and flame microstructures. The results show that the extinction limits were decreased due to the CO2 addition and extended caused by the enhanced pressure, respectively. The changes of flame microstructures from far away from extinction to near extinction mainly are reflected in a narrower combustion zone and thinner flame thickness, while there is no visible displacement of the flame front location. Quantitative analyses manifest the thermal effect of CO2 addition on extinction limit is greater than chemical effect, and elevated pressure can enhance both thermal and chemical effects. An interesting phenomenon occurred between the thermal and chemical effects resulting from increasing CO2 mole fraction in an oxidizer on extinction limit; the former monotonically increase along with CO2 mole fraction, while the latter represents a kind of approximate quadratic-parabola tend along with CO2 mole fraction. The distributions of the production and consumption rate of hydroxyl (OH) radicals were presented to clarify the contribution of the kinetic term in the asymptotic solution to the extinction limits with increasing CO2 molar fraction and various pressures.
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| GB/T 7714 | Chen, Ying , Wang, Jingfu , Li, Jianrong et al. A Numerical Study of CO2 Decoupled Effects on Extinction Limit and Flame Microstructure in CH4/Air Counterflow Diffusion Flame with Various Pressures [J]. | INTERNATIONAL JOURNAL OF ENERGY RESEARCH , 2023 , 2023 . |
| MLA | Chen, Ying et al. "A Numerical Study of CO2 Decoupled Effects on Extinction Limit and Flame Microstructure in CH4/Air Counterflow Diffusion Flame with Various Pressures" . | INTERNATIONAL JOURNAL OF ENERGY RESEARCH 2023 (2023) . |
| APA | Chen, Ying , Wang, Jingfu , Li, Jianrong , Zhang, Jian . A Numerical Study of CO2 Decoupled Effects on Extinction Limit and Flame Microstructure in CH4/Air Counterflow Diffusion Flame with Various Pressures . | INTERNATIONAL JOURNAL OF ENERGY RESEARCH , 2023 , 2023 . |
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Abstract ：
Structural defects in graphene are inevitable during the production process, which have remarkable impacts on the mechanical properties of graphene and further affect the properties of nanocomposite reinforced by graphene. In this work, a bottom-up multiscale approach is employed to investigate the nonlinear dynamics of defective graphene reinforced composite plates from the material properties of nanocomposites to the dynamic behavior of macro-composite plates. The molecular modeling and simulation are conducted by molecular dynamics (MD) to evaluate the effective mechanical properties of pristine graphene, vacancy defective graphene, Stone-Wales defective graphene, poly (methyl methacrylate) (PMMA) and graphene/PMMA composites reinforced by different graphene configurations at the nano-scale. Meanwhile, the fracture mechanism and interfacial interaction energy between graphene and PMMA matrix during the deformation process are examined to explore the enhancement mechanism of nanocomposites. The efficiency parameters are derived by incorporating the MD results and the extended Halpin-Tsai micromechanics model to capture the heterogeneity of nanocomposite at the nano-scale as well as the continuum scale, and then the effective material properties considering the effect of defect, temperature and pressure are substituted into the nonlinear dynamics of functionally graded graphene reinforced composite (FG-GRC) plates at the macro-scale. The governing equations of motion for FG-GRC plates under the aerodynamic pressure are derived based on the third-order shear deformation theory, von-Karman nonlinear strain-displacement relation and Hamilton's principle. The aerodynamic pressure acting on the surface of the plate consists of two parts, one is the static pressure, and the other is the disturbed air flow. Furthermore, Galerkin method and the fourth-order Runge-Kutta method are exploited to discrete and solve the governing equations of motion. The bifurcation, time history and phase diagrams of FG-GRC plates are obtained to analyze the dynamic characteristics of the plates. This study reveals the nonlinear dynamic characteristics of graphene/PMMA composite plate, which contributes to the prediction of dynamic response of composite structure in the aerospace field.
Keyword ：
Aerodynamic Aerodynamic Efficiency parameter Efficiency parameter Multiscale modeling Multiscale modeling Nonlinear dynamics Nonlinear dynamics Molecular dynamics Molecular dynamics
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| GB/T 7714 | Wang, J. F. , Li, X. L. , Shi, S. Q. et al. Multiscale nonlinear dynamics analysis of defective graphene reinforced PMMA composite plates under aerodynamic pressure [J]. | NONLINEAR DYNAMICS , 2023 , 111 (13) : 11851-11884 . |
| MLA | Wang, J. F. et al. "Multiscale nonlinear dynamics analysis of defective graphene reinforced PMMA composite plates under aerodynamic pressure" . | NONLINEAR DYNAMICS 111 . 13 (2023) : 11851-11884 . |
| APA | Wang, J. F. , Li, X. L. , Shi, S. Q. , Guo, X. Y. . Multiscale nonlinear dynamics analysis of defective graphene reinforced PMMA composite plates under aerodynamic pressure . | NONLINEAR DYNAMICS , 2023 , 111 (13) , 11851-11884 . |
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Abstract ：
Delamination is one of the failure modes of functionally graded materials (FGM), resulting in the critical change of vibration characteristics. The Chebyshev polynomials are commonly used as admissible functions to improve the computational efficiency of numerical algorithms and avoid the occurrence of ill-conditioned problems. This paper extends the Chebyshev-Ritz method to the free vibration analysis of delaminated FGM plates, in which the material variation through the plate thickness follows the exponential-law distribution. A plane crack that is considered to be perpendicular to the thickness direction penetrates through the width direction. Based on the region approach, the analysis of FGM plates with a mid-plane delamination is divided into four sub-regions. The kinetic energy and potential energy of each sub-region are derived by the thin plate theory and von Karman nonlinear strain-displacement relation. The modal functions of the displacement fields of FGM plates can be constructed in accordance with the displacement continuity conditions of the delamination interface and the boundary conditions of such plates. The effects of asymmetric material distribution, delamination length ratio, Young's modulus ratio, and boundary support on the vibration behavior of FGM plates are investigated. This semi-analytical study provides a reasonable theoretical basis for the behavior prediction and delamination identification of composite structures.
Keyword ：
FGM plate FGM plate Delamination Delamination Chebyshev polynomials Chebyshev polynomials vibration vibration
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| GB/T 7714 | Wang, J. F. , Cao, G. , Song, Z. W. et al. Dynamic Analysis of FGM Plates with Variable Delamination Parameters by the Chebyshev-Ritz Method [J]. | INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS , 2023 , 23 (16N18) . |
| MLA | Wang, J. F. et al. "Dynamic Analysis of FGM Plates with Variable Delamination Parameters by the Chebyshev-Ritz Method" . | INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS 23 . 16N18 (2023) . |
| APA | Wang, J. F. , Cao, G. , Song, Z. W. , Lai, S. K. . Dynamic Analysis of FGM Plates with Variable Delamination Parameters by the Chebyshev-Ritz Method . | INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS , 2023 , 23 (16N18) . |
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Abstract ：
Owing to the excellent mechanical properties, polymethyl methacrylate (PMMA)/carbon nanotube (CNT) composite has been increasingly adopted in the aerospace field, which is usually subjected to various temperature conditions and supersonic aerodynamic loads. Using a molecular dynamics (MD)-based multiscale simulation, the nonlinear forced vibration of PMMA/CNT composite plate is investigated under coupled temperature and aerodynamic load conditions. The longitudinal, transverse and shear moduli of PMMA/single-walled CNT (SWCNT) nanocomposite obtained from MD simulation at different temperature and pressure levels are substituted into the extended rule of mixtures to establish the constitutive equations of PMMA/CNT composite plate. Meanwhile, Poisson's ratio and thermal expansion coefficient of nanocomposite are used in the constitutive equations. Based on the third-order shear deformation theory, von Karman nonlinear strain-displacement relation and Hamilton's principle, the partial differential equation of composite plate is derived, which is reduced into a set of coupled ordinary differential equations by applying Galerkin method and is solved using the fourth-order Runge-Kutta method. The bifurcation diagrams, phase portraits, time histories and Poincare maps of composite plate are obtained under the complex loads including transverse harmonic excitation and aerodynamic pressure, which are applied to analyze the dynamic characteristics of system. This study reveals the nonlinear dynamic characteristics of PMMA/CNT composite plate, which contributes to the prediction of long-term performance of composite materials in aerospace field.
Keyword ：
Nonlinear dynamics Nonlinear dynamics Efficiency parameter Efficiency parameter Aerodynamic Aerodynamic Composite structure Composite structure Multiscale simulation Multiscale simulation
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| GB/T 7714 | Wang, J. F. , Shi, S. Q. , Liu, Y. Z. et al. Multiscale simulation of temperature- and pressure-dependent nonlinear dynamics of PMMA/CNT composite plates [J]. | NONLINEAR DYNAMICS , 2022 , 109 (3) : 1517-1550 . |
| MLA | Wang, J. F. et al. "Multiscale simulation of temperature- and pressure-dependent nonlinear dynamics of PMMA/CNT composite plates" . | NONLINEAR DYNAMICS 109 . 3 (2022) : 1517-1550 . |
| APA | Wang, J. F. , Shi, S. Q. , Liu, Y. Z. , Yang, J. P. , Tam, Lik-ho . Multiscale simulation of temperature- and pressure-dependent nonlinear dynamics of PMMA/CNT composite plates . | NONLINEAR DYNAMICS , 2022 , 109 (3) , 1517-1550 . |
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Abstract ：
The volume fraction of the carbon nanotube (CNT) plays a key role in ensuring the performance of the CNT reinforced polymer composite, especially under the severe vibration, which leads to the resonance and failure of the composite structure. In this paper, a bottom-up multiscale method is adopted to study the effect of the CNT volume fractions on the nonlinear vibration of the poly (methyl methacrylate) (PMMA)/CNT composite. According to the molecular simulation, the longitudinal, transverse and shear moduli of the PMMA/CNT nanocomposites are found to increase with the increasing CNT volume fractions. Substituting the simulated moduli into the extended rule of mixtures (EROM), the efficiency parameters of the PMMA/CNT composite with various CNT volume fractions are derived based on a homogenization approach. The derived efficiency parameters are used in the functionally graded (FG)-based EROM to obtain the expressions of the longitudinal, transverse and shear moduli of the macroscopic composite plate, so as to obtain the constitutive equation for the nonlinear vibrations of the FG-based PMMA/CNT composite plate. The subsequent meshless simulation results demonstrate that the natural frequencies of the FG-based composite plate increase with the increasing volume fractions, whereas the ratios of the nonlinear to linear frequencies decrease. Using the bottom-up multiscale analysis, the macroscopic vibration responses are analyzed for the PMMA/CNT composites with the CNT volume fractions up to 9.0%, which provides a paradigm of the design of the PMMA/CNT composite by considering the CNT volume fraction effect.
Keyword ：
Meshless simulation Meshless simulation Molecular dynamics Molecular dynamics CNT composite CNT composite Nonlinear vibration Nonlinear vibration CNT volume fraction CNT volume fraction PMMA PMMA
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| GB/T 7714 | Wang, J. F. , Yang, J. P. , Tam, L-H et al. Effect of CNT volume fractions on nonlinear vibrations of PMMA/CNT composite plates: A multiscale simulation [J]. | THIN-WALLED STRUCTURES , 2022 , 170 . |
| MLA | Wang, J. F. et al. "Effect of CNT volume fractions on nonlinear vibrations of PMMA/CNT composite plates: A multiscale simulation" . | THIN-WALLED STRUCTURES 170 (2022) . |
| APA | Wang, J. F. , Yang, J. P. , Tam, L-H , Zhang, W. . Effect of CNT volume fractions on nonlinear vibrations of PMMA/CNT composite plates: A multiscale simulation . | THIN-WALLED STRUCTURES , 2022 , 170 . |
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Abstract ：
Purpose In this paper, the nonlinear vibration behavior of functionally graded carbon nanotube reinforced composite (FG-CNTRC) plates is investigated by meshless method. Methods The efficiency parameters, which clearly affect the mechanical properties of the composite materials, are characterized by polynomial expressions for different CNT contents, and applied as the inputs in the vibration analysis of plate structure. Four distributions of CNTs along the thickness of composite plate are considered, namely, the uniform distribution (UD), FG-O, FG-X and FG-V. Based on the classical plate theory and von Karman strain-displacement relation, the governing equations of motion are derived by the virtual displacement principle. Based on the reproducing kernel particle method (RKPM), the discrete governing equations for the vibration of the FG-CNTRC plates are derived. The linearized updated mode (LUM) method is adopted to solve the iteration process of governing equations. Results Numerical results are employed to investigate the effects of boundary condition, aspect ratio, volume fraction and arrangement of CNT on the nonlinear vibration characteristics of composite plates.
Keyword ：
Reproducing kernel particle method Reproducing kernel particle method Efficiency parameter Efficiency parameter Carbon nanotube Carbon nanotube Nonlinear vibration Nonlinear vibration Functionally graded material Functionally graded material
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| GB/T 7714 | Zhang, W. , He, L. J. , Wang, J. F. . Content-Dependent Nonlinear Vibration of Composite Plates Reinforced with Carbon Nanotubes [J]. | JOURNAL OF VIBRATION ENGINEERING & TECHNOLOGIES , 2022 , 10 (4) : 1253-1264 . |
| MLA | Zhang, W. et al. "Content-Dependent Nonlinear Vibration of Composite Plates Reinforced with Carbon Nanotubes" . | JOURNAL OF VIBRATION ENGINEERING & TECHNOLOGIES 10 . 4 (2022) : 1253-1264 . |
| APA | Zhang, W. , He, L. J. , Wang, J. F. . Content-Dependent Nonlinear Vibration of Composite Plates Reinforced with Carbon Nanotubes . | JOURNAL OF VIBRATION ENGINEERING & TECHNOLOGIES , 2022 , 10 (4) , 1253-1264 . |
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Abstract ：
This paper investigates the thermal vibration and buckling of the functionally graded carbon nanotube reinforced composite (FG-CNTRC) quadrilateral plate using the meshless method. Four distributions of the reinforcements along the thickness direction are considered, which are the uniform distributions (UD), FG-V, FG-O and FG-X. The corresponding effective material properties including Young's modulus, mass density, Poisson's ratio and thermal expansion coefficients are estimated by the rule of mixture with the CNT efficiency parameters accounting for the size-dependence. The first-order shear deformation theory (FSDT) with the consideration of thermal effects is employed. Based on Hamilton's principle and the moving least square (MLS) approximation, the discrete governing equations for the vibration of the FG-CNTRC plate are derived. The free vibration of the regular and irregular plates with and without the temperature effect are considered respectively, and the corresponding natural frequencies and mode shapes are obtained by the eigenvalue problem. The stability analysis of the uniaxial and biaxial mechanical and thermal buckling are also conducted subsequently. The effects of the volume fraction, distribution pattern, geometrical characteristics and temperature on the buckling behaviors of the CNTRC quadrilateral plate are discussed in detail. © 2020 Elsevier Masson SAS
Keyword ：
Reinforcement Reinforcement Buckling Buckling Shear flow Shear flow Vibration analysis Vibration analysis Thermal expansion Thermal expansion Least squares approximations Least squares approximations Shear deformation Shear deformation Structural panels Structural panels Eigenvalues and eigenfunctions Eigenvalues and eigenfunctions Carbon nanotubes Carbon nanotubes Plates (structural components) Plates (structural components) Elastic moduli Elastic moduli
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| GB/T 7714 | Wang, J.F. , Cao, S.H. , Zhang, W. . Thermal vibration and buckling analysis of functionally graded carbon nanotube reinforced composite quadrilateral plate [J]. | Solids , 2021 , 85 . |
| MLA | Wang, J.F. et al. "Thermal vibration and buckling analysis of functionally graded carbon nanotube reinforced composite quadrilateral plate" . | Solids 85 (2021) . |
| APA | Wang, J.F. , Cao, S.H. , Zhang, W. . Thermal vibration and buckling analysis of functionally graded carbon nanotube reinforced composite quadrilateral plate . | Solids , 2021 , 85 . |
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Abstract ：
The circulation pump is an important element limiting the development of small-scale Organic Rankine Cycle system which may have a negative efficiency when the power consumption of the pump is considered and if a suitable pump that corresponds to the working fluid is not properly selected. Based on the consideration mentioned above, in this paper, a trapezoid used to represent the power consumption of the pump and a triangle used to represent the degree of subcooling of the working fluid are defined. Using these two models, the perfection of Organic Rankine Cycle at the optimal condensation temperature relative to the Carnot cycle within the same temperature limitation is analyzed when 69 dry and isentropic working fluids are used in Organic Rankine Cycle. The deviation between the real and ideal gas behavior of each working fluid is also obtained. On this basis, the optimal condensation temperature of each dry and isentropic working fluid is determined. Moreover, the applicability of each organic working fluid in Organic Rankine Cycle is discussed from the viewpoint of pump performance. 36 working fluids are suitable and 33 ones not suitable for the application in small-scale Organic Rankine Cycle system. Suitable pump types corresponding to applicable organic working fluids are also analyzed and determined. The graphic method proposed in this paper and the findings about pump performance can provide reference for the operation of practical Organic Rankine Cycle.
Keyword ：
Graphic method Graphic method Pump performance Pump performance Isentropic fluid Isentropic fluid Organic Rankine Cycle Organic Rankine Cycle Condensation temperature Condensation temperature Dry fluid Dry fluid
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| GB/T 7714 | Zhang, Xinxin , Zhang, Yin , Wang, Jingfu . Evaluation and selection of dry and isentropic working fluids based on their pump performance in small-scale organic Rankine cycle [J]. | APPLIED THERMAL ENGINEERING , 2021 , 191 . |
| MLA | Zhang, Xinxin et al. "Evaluation and selection of dry and isentropic working fluids based on their pump performance in small-scale organic Rankine cycle" . | APPLIED THERMAL ENGINEERING 191 (2021) . |
| APA | Zhang, Xinxin , Zhang, Yin , Wang, Jingfu . Evaluation and selection of dry and isentropic working fluids based on their pump performance in small-scale organic Rankine cycle . | APPLIED THERMAL ENGINEERING , 2021 , 191 . |
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Abstract ：
Ammonia (NH3) is not only expected to be used as a hydrogen energy carrier but also expected to become a carbon-free fuel. Methane (CH4) can be used as a combustion enhancer for improving the combustion intensity of NH3. In addition, it is important to understand the flame characteristics of NH3-air at elevated pressures and temperatures. The laminar flame speed of NH3-CH4-air is numerically investigated, where the mole fraction of CH4 ranges from 0 to 50% in binary fuels and the pressure and initial temperature are up to 10 atm and 1000 K, respectively. The calculated value from the Okafor mechanism is in excellent agreement with experimental data. The CH4 in the fuel affects the flame speed by changing the main species of free radicals in the flame; the high pressure not only increases the rate-limiting reaction rate in the flame but also reduces the amount of H, O, and OH radicals in the flame, so as to restrain the propagation of the flame. At a higher initial temperature, the faster flame speed is mainly due to the higher adiabatic flame temperature. The laminar flame speed correlation equation has a consistent trend with the simulation results, though with a slight underestimation at higher pressures and temperatures. It is a more effective way to calculate the laminar flame speeds of NH3-air for a given pressure and temperature.
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| GB/T 7714 | Zhang Xiaolei , Wang Jingfu , Chen Ying et al. Effect of CH4, Pressure, and Initial Temperature on the Laminar Flame Speed of an NH3-Air Mixture. [J]. | ACS omega , 2021 , 6 (18) : 11857-11868 . |
| MLA | Zhang Xiaolei et al. "Effect of CH4, Pressure, and Initial Temperature on the Laminar Flame Speed of an NH3-Air Mixture." . | ACS omega 6 . 18 (2021) : 11857-11868 . |
| APA | Zhang Xiaolei , Wang Jingfu , Chen Ying , Li Conghao . Effect of CH4, Pressure, and Initial Temperature on the Laminar Flame Speed of an NH3-Air Mixture. . | ACS omega , 2021 , 6 (18) , 11857-11868 . |
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