The heat generation model and three-dimensional computational fluid dynamics model for lithium ion cells were established with boundary conditions defined.In order to provide a better insight about the behaviors of hi...The heat generation model and three-dimensional computational fluid dynamics model for lithium ion cells were established with boundary conditions defined.In order to provide a better insight about the behaviors of high-power lithium ion cells under realistic discharge conditions,the temperature difference of the cells and an active thermal management system with a pure air-cooling mode were analyzed and predicted with the factors affecting the unevenness of temperature field discussed.The results show a significant effect of the cooling flow rate on the temperature rise of the cells for all discharge rates.Average surface temperatures are relatively uniform at lower discharge rate that makes it easier to control the temperature of the pack.Cell temperatures are expected to rise significantly toward the end of discharge and they show non-uniformity at higher discharge rates.Adequate air flow rate of active cooling is required at high discharge rate and high ambient temperature for practical pack thermal management system.展开更多
We examine the effect of the electron exchange-correlation on weak and arbitrary amplitude quantum dust ion-acoustic(QDIA) solitons.The reduced quantum hydrodynamic(QHD) model is used.Carrying out a fully nonlinear an...We examine the effect of the electron exchange-correlation on weak and arbitrary amplitude quantum dust ion-acoustic(QDIA) solitons.The reduced quantum hydrodynamic(QHD) model is used.Carrying out a fully nonlinear analysis,it is found that the effect of the exchange-correlation on the main quantities for solitary-wave propagation can be quite important.In particular,it may be noted that the arbitrary amplitude QDIA soliton experiences a spreading as the phenomenon of exchange-correlation becomes effective.Furthermore,our results show that the exchange-correlation effects inhibit the formation of the flat-bottomed solitons and do not favor their emergence.It turns out that exchangecorrelation and quantum diffraction may act concurrently to set up the conditions for the existence of the QDIA solitary waves.Our results complement and provide new insight into our previously published work on this problem.展开更多
The electrostatic surface waves on semi-bounded quantum electron-hole semiconductor plasmas are studied within the framework of the quantum hydrodynamic model, including the electrons and holes quantum recoil effects,...The electrostatic surface waves on semi-bounded quantum electron-hole semiconductor plasmas are studied within the framework of the quantum hydrodynamic model, including the electrons and holes quantum recoil effects,quantum statistical pressures of the plasma species, as well as exchange and correlation effects. The dispersion characteristics of surface electrostatic oscillations are investigated by using the typical values of Ga As, Ga Sb and Ga N semiconductors. Numerical results show the existence of one low-frequency branch due to the mass difference between the electrons and holes in addition to one high-frequency branch due to charge-separation effects.展开更多
基金supported by the National Natural Science Foundation of China(No.50976011)the Fundamental Research Funds for the Central Universities(No.2009JBM090)
文摘The heat generation model and three-dimensional computational fluid dynamics model for lithium ion cells were established with boundary conditions defined.In order to provide a better insight about the behaviors of high-power lithium ion cells under realistic discharge conditions,the temperature difference of the cells and an active thermal management system with a pure air-cooling mode were analyzed and predicted with the factors affecting the unevenness of temperature field discussed.The results show a significant effect of the cooling flow rate on the temperature rise of the cells for all discharge rates.Average surface temperatures are relatively uniform at lower discharge rate that makes it easier to control the temperature of the pack.Cell temperatures are expected to rise significantly toward the end of discharge and they show non-uniformity at higher discharge rates.Adequate air flow rate of active cooling is required at high discharge rate and high ambient temperature for practical pack thermal management system.
文摘We examine the effect of the electron exchange-correlation on weak and arbitrary amplitude quantum dust ion-acoustic(QDIA) solitons.The reduced quantum hydrodynamic(QHD) model is used.Carrying out a fully nonlinear analysis,it is found that the effect of the exchange-correlation on the main quantities for solitary-wave propagation can be quite important.In particular,it may be noted that the arbitrary amplitude QDIA soliton experiences a spreading as the phenomenon of exchange-correlation becomes effective.Furthermore,our results show that the exchange-correlation effects inhibit the formation of the flat-bottomed solitons and do not favor their emergence.It turns out that exchangecorrelation and quantum diffraction may act concurrently to set up the conditions for the existence of the QDIA solitary waves.Our results complement and provide new insight into our previously published work on this problem.
文摘The electrostatic surface waves on semi-bounded quantum electron-hole semiconductor plasmas are studied within the framework of the quantum hydrodynamic model, including the electrons and holes quantum recoil effects,quantum statistical pressures of the plasma species, as well as exchange and correlation effects. The dispersion characteristics of surface electrostatic oscillations are investigated by using the typical values of Ga As, Ga Sb and Ga N semiconductors. Numerical results show the existence of one low-frequency branch due to the mass difference between the electrons and holes in addition to one high-frequency branch due to charge-separation effects.
