To investigate the steady thermal hydraulic characteristics of U-tube steam generator(SG), a 1D simulation code based on the four-equation drift flux model is developed. The U-tube channels presumably consist mainly o...To investigate the steady thermal hydraulic characteristics of U-tube steam generator(SG), a 1D simulation code based on the four-equation drift flux model is developed. The U-tube channels presumably consist mainly of the primary channel, secondary channel, and tube wall. In the sub-cooling regions of the primary and secondary channels, flow is simulated using the single-phase flow model, whereas that in the boiling regions of the secondary channels is simulated using the four-equation drift flux model. The first-order equations of upwind difference are derived based on the staggered grid. Steady-state thermal hydraulic parameters are obtained with a cross-iteration scheme of heat balance and natural circulation requirement. The developed code is applied to analyze the SG behavior of the Qinshan I Nuclear Power Plant under 100%, 75%, 50%, 30%, and 15% power conditions. Analysis results are then compared with the simulation results obtained using RELAP5.展开更多
In this short review some aspects of applications of free electron theory on the ground of the Fermi statistics will be analyzed. There it is an intention to attempt somebody’s attention to problems in widespread lit...In this short review some aspects of applications of free electron theory on the ground of the Fermi statistics will be analyzed. There it is an intention to attempt somebody’s attention to problems in widespread literature of interpretation of conductivity of metals, superconductor in the normal state and semiconductors with degenerated electron gas. In literature there are many cases when to these materials the classical statistics is applied. It is well known that the electron heat capacity and thermal noise (and as a consequence the electrical conductivity) are determined by randomly moving electrons, which energy is close to the Fermi energy level, and the other part of electrons, which energy is well below the Fermi level can not be scattered and change its energy. Therefore there was tried as simple as possible on the ground of Fermi distribution, and on random motion of charge carriers, and on the well known experimental results to take general expressions for various kinetic parameters which are applicable for materials both without and with degenerated electron gas. It is shown, that drift mobility of randomly moving charge carriers, depending on the degree degeneracy, can considerably exceed the Hall mobility. Also it is shown that the Einstein relation between the diffusion coefficient and the drift mobility of charge carriers is valid even in the case of degeneracy. There also will be presented the main kinetic parameter values for different metals.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.51376065 and 51176052)
文摘To investigate the steady thermal hydraulic characteristics of U-tube steam generator(SG), a 1D simulation code based on the four-equation drift flux model is developed. The U-tube channels presumably consist mainly of the primary channel, secondary channel, and tube wall. In the sub-cooling regions of the primary and secondary channels, flow is simulated using the single-phase flow model, whereas that in the boiling regions of the secondary channels is simulated using the four-equation drift flux model. The first-order equations of upwind difference are derived based on the staggered grid. Steady-state thermal hydraulic parameters are obtained with a cross-iteration scheme of heat balance and natural circulation requirement. The developed code is applied to analyze the SG behavior of the Qinshan I Nuclear Power Plant under 100%, 75%, 50%, 30%, and 15% power conditions. Analysis results are then compared with the simulation results obtained using RELAP5.
文摘In this short review some aspects of applications of free electron theory on the ground of the Fermi statistics will be analyzed. There it is an intention to attempt somebody’s attention to problems in widespread literature of interpretation of conductivity of metals, superconductor in the normal state and semiconductors with degenerated electron gas. In literature there are many cases when to these materials the classical statistics is applied. It is well known that the electron heat capacity and thermal noise (and as a consequence the electrical conductivity) are determined by randomly moving electrons, which energy is close to the Fermi energy level, and the other part of electrons, which energy is well below the Fermi level can not be scattered and change its energy. Therefore there was tried as simple as possible on the ground of Fermi distribution, and on random motion of charge carriers, and on the well known experimental results to take general expressions for various kinetic parameters which are applicable for materials both without and with degenerated electron gas. It is shown, that drift mobility of randomly moving charge carriers, depending on the degree degeneracy, can considerably exceed the Hall mobility. Also it is shown that the Einstein relation between the diffusion coefficient and the drift mobility of charge carriers is valid even in the case of degeneracy. There also will be presented the main kinetic parameter values for different metals.
