By conjugating features of combustion gas jetting flows of the solid-rocket and using mathematical methods, a numerical scheme is systematically derived based on Harten′s standard TVD scheme, which fits for the flow ...By conjugating features of combustion gas jetting flows of the solid-rocket and using mathematical methods, a numerical scheme is systematically derived based on Harten′s standard TVD scheme, which fits for the flow with high temperature, pressure and velocity. The rational calculation formula of pressure partial derivation is also given out. By using the chemical kinetics knowledge, problems of multi-component and finite rate chemical reaction contained in combustion gas of the rocket flow field are discussed. The method for solving the mass source term of chemical reaction is clarified. Taking 9 reaction equations with 12 components as an example and utilizing the established calculation program, the free jetting flow field of the rocket is simulated. Numerical results show the correctness of the numerical scheme.展开更多
Ethane steam cracking process in an industrial reactor was investigated.An one-demsional(1D)steady-state model was developed firstly by using an improved molecular reaction scheme and was then simulated in Aspen Plus....Ethane steam cracking process in an industrial reactor was investigated.An one-demsional(1D)steady-state model was developed firstly by using an improved molecular reaction scheme and was then simulated in Aspen Plus.A comparison of model results with industrial data and previously reported results showed that the model can predict the process kinetics more accurately.In addition,the validated model was used to study the effects of different process variables,including coil outlet temperature(COT),steam-to-ethane ratio and residence time on ethane conversion,ethylene selectivity,products yields,and coking rate.Finally,steady-state optimization was conducted to the operation of industrial reactor.The COT and steam-to-ethane ratio were taken as decision variables to maximize the annual operational profit.展开更多
A parallelized upwind flux splitting scheme for supersonic reacting flows on hybrid meshes is presented. The complexity of super/hyper-sonic combustion flows makes it necessary to establish solvers with higher resolut...A parallelized upwind flux splitting scheme for supersonic reacting flows on hybrid meshes is presented. The complexity of super/hyper-sonic combustion flows makes it necessary to establish solvers with higher resolution and efficiency for multi-component Euler/N-S equations. Hence, a spatial second-order van Leer type flux vector splitting scheme is established by introducing auxiliary points in interpolation, and a domain decomposition method used on unstructured hybrid meshes for obtaining high calculating efficiency. The numerical scheme with five-stage Runge-Kutta time step method is implemented to the simulation of combustion flows, including the supersonic hydrogen/air combustion and the normal injection of hydrogen into reacting flows. Satisfying results are obtained compared with limited references.展开更多
A scheme of the processes in Fenton solution with various substances is offered, and the channels of light formation registered by the luminometer are analyzed. Under the proposed scheme we discuss the possibilities o...A scheme of the processes in Fenton solution with various substances is offered, and the channels of light formation registered by the luminometer are analyzed. Under the proposed scheme we discuss the possibilities of studying the properties of antioxidants and prooxidants. Oxidation of alanine, albumin and sodium oxalate have been taken as an example. The properties of ascorbic acid and the mechanism of display of its oxidant and prooxidant properties are analyzed herewith. Methodical questions of the chemiluminescence research in Fenton solution such as the selection of reagents concentration, water preparation and the effect of the background radiation have been considered in this study as well.展开更多
This paper is concerned with some nonlinear reaction - diffusion models. To solve this kind of models, the modified Laplace finite element scheme and the alternating direction finite element scheme are established for...This paper is concerned with some nonlinear reaction - diffusion models. To solve this kind of models, the modified Laplace finite element scheme and the alternating direction finite element scheme are established for the system of patrical differential equations. Besides, the finite difference method is utilized for the ordinary differential equation in the models. Moreover, by the theory and technique of prior estimates for the differential equations, the convergence analyses and the optimal L2- norm error estimates are demonstrated.展开更多
文摘By conjugating features of combustion gas jetting flows of the solid-rocket and using mathematical methods, a numerical scheme is systematically derived based on Harten′s standard TVD scheme, which fits for the flow with high temperature, pressure and velocity. The rational calculation formula of pressure partial derivation is also given out. By using the chemical kinetics knowledge, problems of multi-component and finite rate chemical reaction contained in combustion gas of the rocket flow field are discussed. The method for solving the mass source term of chemical reaction is clarified. Taking 9 reaction equations with 12 components as an example and utilizing the established calculation program, the free jetting flow field of the rocket is simulated. Numerical results show the correctness of the numerical scheme.
基金The financial support provided by the Project of National Natural Science Foundation of China(21822809&21978256)the Fundamental Research Funds for the Central Universitiesthe Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(Grant No.2018-K23)are gratefully acknowledged.
文摘Ethane steam cracking process in an industrial reactor was investigated.An one-demsional(1D)steady-state model was developed firstly by using an improved molecular reaction scheme and was then simulated in Aspen Plus.A comparison of model results with industrial data and previously reported results showed that the model can predict the process kinetics more accurately.In addition,the validated model was used to study the effects of different process variables,including coil outlet temperature(COT),steam-to-ethane ratio and residence time on ethane conversion,ethylene selectivity,products yields,and coking rate.Finally,steady-state optimization was conducted to the operation of industrial reactor.The COT and steam-to-ethane ratio were taken as decision variables to maximize the annual operational profit.
文摘A parallelized upwind flux splitting scheme for supersonic reacting flows on hybrid meshes is presented. The complexity of super/hyper-sonic combustion flows makes it necessary to establish solvers with higher resolution and efficiency for multi-component Euler/N-S equations. Hence, a spatial second-order van Leer type flux vector splitting scheme is established by introducing auxiliary points in interpolation, and a domain decomposition method used on unstructured hybrid meshes for obtaining high calculating efficiency. The numerical scheme with five-stage Runge-Kutta time step method is implemented to the simulation of combustion flows, including the supersonic hydrogen/air combustion and the normal injection of hydrogen into reacting flows. Satisfying results are obtained compared with limited references.
文摘A scheme of the processes in Fenton solution with various substances is offered, and the channels of light formation registered by the luminometer are analyzed. Under the proposed scheme we discuss the possibilities of studying the properties of antioxidants and prooxidants. Oxidation of alanine, albumin and sodium oxalate have been taken as an example. The properties of ascorbic acid and the mechanism of display of its oxidant and prooxidant properties are analyzed herewith. Methodical questions of the chemiluminescence research in Fenton solution such as the selection of reagents concentration, water preparation and the effect of the background radiation have been considered in this study as well.
文摘This paper is concerned with some nonlinear reaction - diffusion models. To solve this kind of models, the modified Laplace finite element scheme and the alternating direction finite element scheme are established for the system of patrical differential equations. Besides, the finite difference method is utilized for the ordinary differential equation in the models. Moreover, by the theory and technique of prior estimates for the differential equations, the convergence analyses and the optimal L2- norm error estimates are demonstrated.
