Research On The Coupled Flow And Heat Analysis Algorithm Of Complex Components Based On Overset Grids

With the rapid development of computer technology and numerical calculation methods,computational fluid dynamics（CFD）plays an important role in various fields of engineering.The numerical simulation of multi-body relative motion of complex components is a common problem.The mesh generation of complex components is not easy and the general method is difficult to deal with the components have relative motion in this kind of problem.Overset grid technology is widely used which has the ability to deal with dynamic motion problems efficiently,reduces the difficulty of complex component mesh generation and maintain high mesh quality.The main work of this paper is to deeply study the relevant methods of the key steps in the process of overset grid assembly and program the numerical solution algorithm of the control equation.The purpose is to develop an efficient numerical simulation method suitable for the relative motion of complex components.In the research of overset grid assembly method,the generation algorithms of structured and unstructured grid are programmed and the key technologies in structured overset grid and unstructured overset grid such as hole cutting,donor cell search and determination of interpolation cell are deeply studied.Aiming at the shortcomings of large memory and low computational efficiency of hole mapping method in the process of structured overset grid,an improved hole mapping method is proposed.The interpolated boundary cells are defined according to the quality of the cell,which is the product of the mesh size and the wall distance in the unstructured overset mesh.The neighbor cell search method is used to improve the efficiency in the donor cell search.The flow field information is interpolated by using the interpolation boundary cell to complete the overall calculation of the flow field.The flow control equation and the numerical solution method of flow heat coupling are studied and programmed in order to solve the flow field.The flow control equation is N-S equation.The finite volume method is used for spatial discretization.The time discretization is double time step method.The turbulence model is S-A equation model and k-ω SST two equation model.The continuity equation,momentum equation and energy equation are solved directly to obtain the distribution of flow field for compressible flow.SIMPLE algorithm is used to solve incompressible flow.The collocated grid is used to make the program more concise.The momentum interpolation method proposed by Rhie and Chow is used to eliminate the non physical pressure oscillation caused by the collocated grid.The SIMPLE algorithm is extended to the calculation of compressible flow by using the density delay correction method.A general numerical simulation framework and related functional module framework for computational fluid dynamics and numerical heat transfer are proposed.The flow and heat transfer process of heat dissipation chip,the flow field of Caradonna Tung rotor and the unsteady disturbance of rotor 67 compressor are simulated in order to apply the overset grid method to the problem of multi-body relative motion.The comparison between numerical results and experimental results shows that the overset grid method is accurate and effective,reduces the difficulty of grid generation,solves the problem of fluid heat coupling numerical simulation of the relative motion of complex components.