Five coal char samples were burnt in thermobalance with ramp heating rate of 30 K/min. The pore structure of these char samples was studied through mercury intrusion method. Combined with the kinetic theory of gases, ...Five coal char samples were burnt in thermobalance with ramp heating rate of 30 K/min. The pore structure of these char samples was studied through mercury intrusion method. Combined with the kinetic theory of gases, the data of surface area was used in fitting the results. As a result, the kinetic triplet was given. The analysis showed that five char samples share almost the same intrinsic activation energy of the overall reaction. The phenomenological implication of the derived combustion rate equation was given.展开更多
The previous paper Ref. [1] showed how to calculate activation energies for ideal gas reactions from the CDF （cumulative distribution function） of the MBD （Maxwell Boltzmann Distribution） and the heat capacity dat...The previous paper Ref. [1] showed how to calculate activation energies for ideal gas reactions from the CDF （cumulative distribution function） of the MBD （Maxwell Boltzmann Distribution） and the heat capacity data of the components. The results presented here show comparisons of activation energies of four ideal gases calculated in that way with those calculated from the ND （Normal Distribution） and its CDF. The evaluation of the CDF for the MBD in Ref. [1] required extensive numerical integrations for each substance. In this paper this method of calculating activation energies is generalised, by showing the CDF is a unique function, independent of temperature and composition, enabling the CDF to be presented graphically or in tabular form. These activation energies are compared to those calculated from the ND and its CDF. The MBD is related to the ND because it has a generating function which is shown here to have the simple form （1-kT）-1.5. The activation energies obtained from the CDF of the ND are shown to agree ca. 5-7% with those obtained directly from the MBD. Because existing thermodynamic treatments are based on average properties, they cannot give either a complete account of thermodynamic controlled and kinetic controlled equilibrium states or explain transitions between them. Complete treatments must include effects from the MBD which are the causes of kinetic controlled equilibrium. The basis for a complete treatment is outlined, which includes the standard deviations and activation energies.展开更多
Research on the dynamic properties of a plasma sheath coupled with pitching motion of the vehicle has great significance in solving the problem of communication interruption in the process of vehicle reentry.This pape...Research on the dynamic properties of a plasma sheath coupled with pitching motion of the vehicle has great significance in solving the problem of communication interruption in the process of vehicle reentry.This paper investigates the dynamic properties of the plasma sheath by using the simplified conventional Burnett(SCB)equations and the Navier-Stokes(NS)equations with the thermochemical non-equilibrium effect.The eleven-species chemical kinetic models are applied to the comparison and there is verification of a dynamic plasma sheath simulation for the first time.After the introduction of vehicle pitching motion,the dynamic results are more consistent with the experimental data than the simulated results when treating it as static state.The plasma sheath characteristic parameters show periodic properties,whose changing period is the same as the pitching motion period.However,because of different velocities of the pitching motion,phase shifts exist in different positions of the vehicle.The enhancement of the rarefied effect weakens the disturbance to the plasma sheath.This research reveals the distribution and regularities of the dynamic plasma sheath.It is significant in solving the ionization blackout problem and the design of the reentry vehicle,and provides reliable data for further research on the dynamic plasma sheath.展开更多
In this paper, the methodology of non-equilibrium thermodynamics is introduced for kinetics research of CO2 capture by ionic liquids, and the following three key scientific problems are proposed to apply the methodolo...In this paper, the methodology of non-equilibrium thermodynamics is introduced for kinetics research of CO2 capture by ionic liquids, and the following three key scientific problems are proposed to apply the methodology in kinetics research of CO2 capture by ionic liquids: reliable thermodynamic models, interfacial transport rate description and accurate experimental flux. The obtaining of accurate experimental flux requires reliable experimental kinetics data and the effective transport area in the CO2 capture process by ionic liquids. Research advances in the three key scientific problems are reviewed systematically and further work is analyzed. Finally, perspectives of non-equilibrium thermodynamic research of the kinetics of CO2 capture by ionic liquids are proposed.展开更多
基金The work was subsidized by the Special Funds for Major State Basic Research Projects(973).project number G1999022205.
文摘Five coal char samples were burnt in thermobalance with ramp heating rate of 30 K/min. The pore structure of these char samples was studied through mercury intrusion method. Combined with the kinetic theory of gases, the data of surface area was used in fitting the results. As a result, the kinetic triplet was given. The analysis showed that five char samples share almost the same intrinsic activation energy of the overall reaction. The phenomenological implication of the derived combustion rate equation was given.
文摘The previous paper Ref. [1] showed how to calculate activation energies for ideal gas reactions from the CDF （cumulative distribution function） of the MBD （Maxwell Boltzmann Distribution） and the heat capacity data of the components. The results presented here show comparisons of activation energies of four ideal gases calculated in that way with those calculated from the ND （Normal Distribution） and its CDF. The evaluation of the CDF for the MBD in Ref. [1] required extensive numerical integrations for each substance. In this paper this method of calculating activation energies is generalised, by showing the CDF is a unique function, independent of temperature and composition, enabling the CDF to be presented graphically or in tabular form. These activation energies are compared to those calculated from the ND and its CDF. The MBD is related to the ND because it has a generating function which is shown here to have the simple form （1-kT）-1.5. The activation energies obtained from the CDF of the ND are shown to agree ca. 5-7% with those obtained directly from the MBD. Because existing thermodynamic treatments are based on average properties, they cannot give either a complete account of thermodynamic controlled and kinetic controlled equilibrium states or explain transitions between them. Complete treatments must include effects from the MBD which are the causes of kinetic controlled equilibrium. The basis for a complete treatment is outlined, which includes the standard deviations and activation energies.
文摘Research on the dynamic properties of a plasma sheath coupled with pitching motion of the vehicle has great significance in solving the problem of communication interruption in the process of vehicle reentry.This paper investigates the dynamic properties of the plasma sheath by using the simplified conventional Burnett(SCB)equations and the Navier-Stokes(NS)equations with the thermochemical non-equilibrium effect.The eleven-species chemical kinetic models are applied to the comparison and there is verification of a dynamic plasma sheath simulation for the first time.After the introduction of vehicle pitching motion,the dynamic results are more consistent with the experimental data than the simulated results when treating it as static state.The plasma sheath characteristic parameters show periodic properties,whose changing period is the same as the pitching motion period.However,because of different velocities of the pitching motion,phase shifts exist in different positions of the vehicle.The enhancement of the rarefied effect weakens the disturbance to the plasma sheath.This research reveals the distribution and regularities of the dynamic plasma sheath.It is significant in solving the ionization blackout problem and the design of the reentry vehicle,and provides reliable data for further research on the dynamic plasma sheath.
基金supported by the National Basic Research Program of China (2009CB226103, 2009CB219902)Swedish Research Councilgrateful to the support by the 363rd Session of Xiangshan Science Conferences, "Scientific Issues of Energy Conservation Mechanism for Waste-decreasing Process"
文摘In this paper, the methodology of non-equilibrium thermodynamics is introduced for kinetics research of CO2 capture by ionic liquids, and the following three key scientific problems are proposed to apply the methodology in kinetics research of CO2 capture by ionic liquids: reliable thermodynamic models, interfacial transport rate description and accurate experimental flux. The obtaining of accurate experimental flux requires reliable experimental kinetics data and the effective transport area in the CO2 capture process by ionic liquids. Research advances in the three key scientific problems are reviewed systematically and further work is analyzed. Finally, perspectives of non-equilibrium thermodynamic research of the kinetics of CO2 capture by ionic liquids are proposed.
