A heterogeneous model is developed for the regeneration of the Cr2O3/Al2O3 catalyst for the propane dehydrogenation process by considering the internal mass transfer and external mass/heat transfer during the coke com...A heterogeneous model is developed for the regeneration of the Cr2O3/Al2O3 catalyst for the propane dehydrogenation process by considering the internal mass transfer and external mass/heat transfer during the coke combustion.Simulation shows that under practical operating conditions,multi-steady states exist for the catalyst pellets and the catalyst temperature is sensitive to gas temperature.However,at increased mass flow rate or lowered oxygen concentration,multi-steady states will not appear.Under the strong influences of film diffusion,the coke in the packed bed reactor will first be exhausted at the inlet,while if the film diffusion resistance is decreased,the position of first coke exhaustion moves toward the outlet of the reactor.展开更多
A modified large-eddy simulation model,the dynamic coherent eddy model(DCEM)is employed to simulate the generation and propagation of internal solitary waves(ISWs)of both depression and elevation type,with wave amplit...A modified large-eddy simulation model,the dynamic coherent eddy model(DCEM)is employed to simulate the generation and propagation of internal solitary waves(ISWs)of both depression and elevation type,with wave amplitudes ranging from small,medium to large scales.The simulation results agree well with the existing experimental data.The generation process of ISWs is successfully captured by the DCEM method.Shear instabilities and diapycnal mixing in the initial wave generation phase are observed.The dissipation rate is not equal at different locations of an ISW.ISW-induced velocity field is analyzed in the present study.The structure of the bottom boundary layer(BBL)of internal wave packets is found to be different from that of a single ISW.A reverse boundary jet instead of a separation bubble exists behind the leading internal wave while separation bubbles appear in other parts of the wave-induced velocity field.The boundary jet flow resulting from the adverse pressure gradients has distinctive dynamics compared with free shear jets.展开更多
Penicillin fermentation is an important part of microbial fermentation. Due to the existence of error date in the independent variables and dependent variables of the penicillin fermentation sample data, the accuracy ...Penicillin fermentation is an important part of microbial fermentation. Due to the existence of error date in the independent variables and dependent variables of the penicillin fermentation sample data, the accuracy of the model of penicillin fermentation is affected. In this paper, an amended harmony search （AHS） algorithm is developed to adjust the hyper-parameters of least squares support vector machine （LS-SVM） in order to build penicillin fermentation process model with prediction accuracy. The AHS algorithm is investigated by unconstrained benchmark functions with different characteristics. Compared with other several optimization approaches, AHS demonstrates a better performance. Moreover, using the simulation data from the PenSim simulation platform to validate the effectiveness of the penicillin fermentation process modeling, experiment results show that the penicillin fermentation process modeling based on the tuned LS-SVM by AHS possesses robustness and generalization ability.展开更多
基金Supported by the National Natural Science Foundation of China（20736011） the Ministry of Education of China（IRT0721）
文摘A heterogeneous model is developed for the regeneration of the Cr2O3/Al2O3 catalyst for the propane dehydrogenation process by considering the internal mass transfer and external mass/heat transfer during the coke combustion.Simulation shows that under practical operating conditions,multi-steady states exist for the catalyst pellets and the catalyst temperature is sensitive to gas temperature.However,at increased mass flow rate or lowered oxygen concentration,multi-steady states will not appear.Under the strong influences of film diffusion,the coke in the packed bed reactor will first be exhausted at the inlet,while if the film diffusion resistance is decreased,the position of first coke exhaustion moves toward the outlet of the reactor.
基金supported by the National Natural Science Foundation of China(Grant No.51179058)the State Key Program of National Natural Science of China(Grant No.51239003)+2 种基金the Special Fund for Public Welfare of Water Resources Ministry(Grant No.201201017)the 111 Project(Grant No.B12032)the Innovation Project of Scientific Research for College Graduates of Jiangsu(Grant No.CXZZ12_0244)
文摘A modified large-eddy simulation model,the dynamic coherent eddy model(DCEM)is employed to simulate the generation and propagation of internal solitary waves(ISWs)of both depression and elevation type,with wave amplitudes ranging from small,medium to large scales.The simulation results agree well with the existing experimental data.The generation process of ISWs is successfully captured by the DCEM method.Shear instabilities and diapycnal mixing in the initial wave generation phase are observed.The dissipation rate is not equal at different locations of an ISW.ISW-induced velocity field is analyzed in the present study.The structure of the bottom boundary layer(BBL)of internal wave packets is found to be different from that of a single ISW.A reverse boundary jet instead of a separation bubble exists behind the leading internal wave while separation bubbles appear in other parts of the wave-induced velocity field.The boundary jet flow resulting from the adverse pressure gradients has distinctive dynamics compared with free shear jets.
基金The authors wish to thank the editor and anonymous referees for their constructive comments and recommendations, which have significantly improved the presentation of this paper. This work is supported by National Nature Science Foundation of China （Grant Nos. 60674021, 61273155）.
文摘Penicillin fermentation is an important part of microbial fermentation. Due to the existence of error date in the independent variables and dependent variables of the penicillin fermentation sample data, the accuracy of the model of penicillin fermentation is affected. In this paper, an amended harmony search （AHS） algorithm is developed to adjust the hyper-parameters of least squares support vector machine （LS-SVM） in order to build penicillin fermentation process model with prediction accuracy. The AHS algorithm is investigated by unconstrained benchmark functions with different characteristics. Compared with other several optimization approaches, AHS demonstrates a better performance. Moreover, using the simulation data from the PenSim simulation platform to validate the effectiveness of the penicillin fermentation process modeling, experiment results show that the penicillin fermentation process modeling based on the tuned LS-SVM by AHS possesses robustness and generalization ability.
