摘要:

A comparison of the surface pseudosources method (SPSM) with other numerical methods for the solution of the neutron transport equation is presented. Unlike most approaches where the first flight Green's function is used, the surface pseudosources method is based on the use of the Green's function of infinite homogenous media. The resulting algebraic system of equations has essential less unknowns than in other methods. Therefore it has a lower number of unknowns. Moreover, coefficients of these algebraic equations can be easily calculated. These two properties of the SPSM method allow us to construct very efficient algorithms for solutions of the transport equation.

ISSN:0041-1450    

DOI:10.1080/00411459808205647

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

An asymptotic-induced scheme for nonstationary transport equations with the diffusion scaling developed in [12] is presented. The scheme works uniformly for all ranges of mean free paths. It is based on the asymptotic analysis of the diffusion limit of the transport equation. Numerical results for different physical situations are shown.

ISSN:0041-1450    

DOI:10.1080/00411459808205648

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The effect of a random transport cross section on the transverse spreading of a pencil beam of charged particles is analysed using the Fermi approximation to the 3D transport equation, in conjunction with a Gaussian model of cross section fluctuations. Stochasticity is seen to enhance the spreading of the beam but ensemble averaged quantities such as the transverse spatial moments and the scalar flux appear not to be sensitive to the details of the underlying statistical model. Furthermore, only asymptotic solutions for the scalar flux are possible because of divergent behaviour that can be traced to an inconsistency between the assumption of forward peakedness of the angular flux. which underlies the Fermi approximation, and the spreading induced by the randomness of the material properties.

ISSN:0041-1450    

DOI:10.1080/00411459808205649

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A modified method of 13 moments based on the first order Chapman-Enskog solution rather than the corresponding Hermite polynomials is proposed. Contrary to the Grad 13 moments equations the equations are correct to first order in the Knudsen number, having correct heat conductivity and viscosity and thus Prandtl number. The relaxation times and coupling coefficient between heat current and viscous pressure are calculated.

ISSN:0041-1450    

DOI:10.1080/00411459808205650

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The critical neutron flux flattening problem governed by the transport equation is studied in a nonuniform slab with vacuum boundary conditions. Existence and uniqueness theorem of the optimal solution is shown in continuous function space. And it is shown that the continuous-space discrete-ordinates approximation converges to the exact optimal solution while the corresponding controllable function converges in the sense of weak star topology.

ISSN:0041-1450    

DOI:10.1080/00411459808205651

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0041-1450    

DOI:10.1080/00411459808205636

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor