Considering fuel flow effect of reactor, neutron dynamic model was derived based on particle conservation equation and coupled with flow and heat transfer model. We developed a three-dimensional neutron/thermal-hydraulic coupled code and analyzed psychical property and thermal hydraulic characteristic of MOSART in transient state. It indicates that thermal hydraulic parameters influence greatly to psychical property of the core. Temperature negative feedback of liquid-fuel MSR is obvious.

Due to non-convex and non-continuous complexity of MINLP problems, heuristic methods are subject to numerous local optima. A novel random walking algorithm with compulsive evolution (RWCE) is an efficient global optimization method for HENS, where probability δ of accepting imperfect network is able to keep population diversity and jump out of local optima effectively during evolution process. In this paper, strong ability of parameter δ to detect promising structure is proved. Structure of evolution process is compared and analyzed under different parameters. Furthermore, a strategy for accepting imperfect network oriented with number of heat exchangers is proposed to improve computational time and evolution ability of optimization. The strategy was applied to several cases taken from literature. It shows better performance of global optimization.

A double medium mathematical model for coalbed methane displacement with gas injection is established. Multi-physics coupling process containing Darcy flow,adsorption/desorption and diffusion of multiple component gas and variation of porosity and permeability is involved. The model is solved numerically with finite difference method and validity of the model is verified. In example simulation calculations,improved recovery,evolution of produced gas composition and variation of coal seam properties under injection of CO₂、N₂and 70% N₂+ 30% CO₂ are contrastively analyzed. It indicates that injections of CO₂、N₂and their mixed gas are able to improve coalbed methane recovery significantly by a degree over 28 %. N₂ breaks through rapidly after injected,while CO₂ occurs in production well later. Shrinkage /swell effect plays a dominant role in variation of porosity and permeability after gas injection.Adsorption of CO₂ reduces porosity and permeability,while adsorption of N₂ leads their increase.

A modified PEBI grid generation method with frontal approach is proposed,which is used to investigate reservoir modeling.Validity of the PEBI grid generation method is shown by comparing results of a self-developed reservoir simulator with that of a software CMG.A synthetic case with irregular boundary is investigated.It shows that PEBI grids reduce influence of grid orientation compared with conventional Cartesian grids.It is favorable to describe complex reservoir boundaries accurately and to implant internal constraints such as vertical well,fault in PEBI grid generation method.

With quasi-classical approximations, statistic properties of Fermi gas in a strong magnetic field at high temperatures are studied. Analytical statistic characteristic quantities are given,and effects of magnetic field as well as temperature on statistic properties of the system are analyzed. Compared with a system in low temperatures.statiBtic characteristic quantities of Fermi gas in a strong magnetic field at high temperatures do not oscillate.The magnetic field deorease total energy of the system,and increases the chemical potential,heat capacity,entropy,pressure and stability of the system-The higher the temperature is,the weaker effects of magnetic field on total energy and heat caDacity and the stronger effects on chemical potential are.

A muhi-component mathematical model characterizing polymer enhanced foam flooding filtration is established with mass conservation principle of foam components. Considering combination of foam generation, coalescence and migration phenomena, the model effectively reflects mechanism of oil phase foam coalescence and polymer foam stabilizing. Differential numerical solution is conducted with adaptive implicit method. Validity of the mathematical model is verified with experiment. Meanwhile, taken foam flooding pilot region of a oilfield, a numerical simulator is employed to study filtration characteristics of enhanced foam flooding. It is indicated that the foam system could exist stably in the formation and gradually advance to production wells to improve oil recovery.

By using explicit saturation and implicit concentration methods,numerical solution is presented to the polymer drive model characterizing dispersion and adsorption of polymer solution flowing through a porous medium.Saturation equation is solved by using an explicit total variation diminishing(TVD)method.To ensure the stability of concentration equation calculation,Crank-Nicolson difference format is used in spatial discretization,and variable is quasi-linear disposed in temporal discretization.The validity of the method presented is verified by comparison with analytic solutions.The calculated example indicates that dispersion causes dilution and dissipation of polymer solutions,and adsorption results in a loss,thus leading to lagging of concentration propagation.Also,the important polymer flooding mechanism- "oil block" is illustrated in the results of calculation.Under the condition of slug injection,the breakthrough time of oil enrichment zone lies between the breakthrough time of polymer concentration front and polymer concentration peak.

In the traditional heat transfer computation,laser heating is always treated as one kind of special boundary conditions,that is, the second boundary condition,which is not fit for the real condition of laser absorption,especially for the thin layer porous material.Differently from the traditional methods,the laser heating is regarded as an inner thermal source and it is assumed that the intensity of the laser attenuates exponentially with its penetration depth.Since evident non Fourier heat conduction effects may appear in thin layer porous materials heated by the high intensity laser pulse,the hyperbolic non Fourier heat conduction model is used to describe this heat transfer case and the corresponding numerical solution is obtained with the finite difference method.According to the obtained solution,some correlations of the non Fourier effect and the optical property of the heated materials are obtained too.

A stripedly distributed transfer function method with infinite elements is introduced, which is used to analyze the guided waves in optical channel waveguides. Two kinds of infinite elements are provided conesponding to analytic direction and discrete direction. In order to simplify the expression of the infinite elements, second order equations of transfer function is chosen with account taken of the character of Helmholtz equation. Numerical results are presented for rectangular waveguides and compaied with those of other methods. The results show the advantage of this method.

A new automatic and semi automatic numerical inversion of Laplace transform method based on Laguerre polynomial is presented.The optimum choice of transform parameters is introduced and the numerical results are also given.

Analytical solutions of the freezing of phase change material (PCM) in annular space are presented. Firstly, approximate integral method and numerical simulation are used to analyze the heat transfer process during the freezing of the PCM in annular space with internal boundary cooled and external boundary insulated.Secondly, a comparison is made between the results obtained by approximate integaral method and the numerical solution. Then, the effects of all kinds of parameters on the freezing process are discussed. Finally, two important conclusions are summarized:1.when the ratio of the inside diameter to the outside one of the PCM is not less than 0.6, we can assume a quadratic temperature distribution in PCM instead of a log arithmic one so as to cut down the efforts used in solving process, and the error will not exceed 1.5%;2. approximate integral method is not apropriate for solving those solid-liquid phase change problems which possess a low Stefan number.