Multiphysics Coupling Framework And Calculation Based On Object Oriented Method

With the development of advanced algorithms and the rapid development of computer technology,multi-physics and multi-scale simulation have become possible.One of the key objects of numerical reactor research is to carry out multi-physics research,to couple the isolated physical processes in the past.Get rid of various approximations and simplifications,and move closer to high-fidelity and high-precision calculations.At present,the process of complex multi-physics is usually solved by decoupling the multiphysics problems into a plurality of independent physical processes.Each of them is solved in a special application program and then the variables to be coupled are taken as the boundary condition.Coupling computation is realized through data exchange between applications.Although this method can get results,the mathematical model can not accurately describe thereal process.The results of the calculation are not convicing.By investigating the MOOSE application in the United States,study the method for realizing full coupling of multi-physics in the framework.Based on the scope of finite element application,dicussing the basic method and inner function for constructing a computational framework which can respond to nuclear field's computation demand and design it.As the research of finite element is not perfect in many fields,it is necessary to know the solution and the limitation of the physical field model before we calculate the coupling of multi-physical fields.Take the CFD field as an example,in order to meet the high-precision calculation requirements,the reasons that affect the calculation precision are explored from the finite element calculation mechanism.The order of interpolation functions is the main discussion object.The influence of different interpolation function order and interpolation function type on CFD calculation accuracy is compared with the lid-driven test which is made by GHIA.Based on the accuracy of the above finite element calculation,it is applied to the multi physical coupling calculation.In the multi-physics coupling calculation,two examples of strong and weak coupling are selected to discucc the influence of the coupling method on the calculation results.The deformation of metal tube is simulated by using the loose coupling,the tight coupling and the full coupling method respectively.In the tight coupling problem,choose the MSRE as a model.Using the tight coupling and full coupling method to finish neutronics-thermal coupling calculation.Explore the influence of coupling method on the result of different multi-physics problems.