Simulation Study Of ES-FEM-ISPH Coupling Method For Thermal Fluid Structure Interaction Problem

The thermal fluid structure interaction problem widely exists in the engineering fields and daily life,such as aerospace,glass production,energy,heat dissipation of electronic equipment.In the thermal fluid structure interaction problem,there are thermal-fluid coupling,thermal-structure coupling and fluid-structure interaction at the same time.This is a very complex and highly nonlinear problem,and it is difficult to obtain an analytical solution for this type of problem through mathematical methods.At the same time,it is also difficult to obtain ideal results by experiments.Therefore,developing an effective and accurate numerical simulation method for solving the thermal fluid structure interaction problem has great application value and prospects.At present,the numerical simulation of the thermal fluid structure interaction problem is mainly based on mesh-based methods,usually using Lagrangian mesh to solve structure domain and Eulerian mesh to solve fluid domain,including Arbitrary Lagrangian Eulerian and Immersed boundary method.However,the Eulerian mesh has certain difficulties in dealing with free surfaces and moving interfaces.The Lagrangian mesh can naturally track free surfaces and moving interfaces when solving the thermal fluid structure interaction problem,which has special advantages over the Eulerian mesh.This thesis develops an edge-based smoothed finite element method(ES-FEM)and incompressible smoothed particle hydrodynamics(ISPH)coupling method to solve the thermal fluid structure interaction problem under the unified Lagrangian description,which is expected to provide an effective numerical simulation method for solving this problem.The main work and research contents of this thesis are as follows:(1)Introduces the basic principles of SPH,including integral representation of functions and particle approximation,discrete forms of equations,correction techniques.The pressure solution method of ISPH is studied,the velocity divergence is zero and the projection method is used to establish the pressure Poisson equation,and the pressure is solved by solving the pressure Poisson equation,so as to obtain a smooth pressure field and avoid pressure oscillation.Studys ISPH correction technology,introduces kernel gradient correction(KGC)algorithm and particle shifting technique(PST)to improve the accuracy and stability of calculation.(2)The ES-FEM-ISPH coupling method for simulating the thermal fluid structure interaction problem is proposed.Research on thermal fluid structure coupling interface processing method,including fluid-structure coupling boundary processing algorithm and thermal-fluid-structure coupling conjugate heat transfer algorithm.Applying ghost particle-based thermal fluid structure interaction interface processing method can satisfy kinematics conditions,dynamics conditions,energy conservation conditions and temperature continuity conditions at the boundary between fluid and structure.The ES-FEMISPH coupling method for simulating the thermal fluid structure interaction problem is proposed,and the validity and accuracy of the ES-FEM-ISPH coupling method are verified by numerical examples.(3)Based on the ES-FEM-ISPH coupling method,the mechanism research on the thermal fluid structure interaction problem of natural convection heat transfer with elastic structure in the cavity has been carried out.Studys the influence of elastic structure and thermal fluid structure interaction on the natural convective heat transfer in the cavity under different conditions or parameters,including temperature boundary conditions,specific heat capacity and thermal conductivity of the fluid,and length,thickness,specific heat capacity,thermal conductivity and Young’s modulus of the elastic structure.