Data Transmission Among Non-Matching Meshes On Fluid-Structural Interfaces Of Impellers

The impeller of centrifugal compressor is the only component to pass mechanical energy to gas, in order to enhance the energy of gas. This means that the interaction between the impeller and the gas is a typical fluid-structure interaction problem. Hence, for accurate mechanical analysis of impeller, the effect of aerodynamic loads must be considered. However, when using numerical methods for analysis of fluid-structure interaction, the discrete meshes used in fluid domain is always much finer than the solid domain, which leads to the meshes do not have to match at their common interface. Therefore, It’s no longer directly to exchange information over this interface, and some coupling method which can deal with the data transfer is a must.In recent years, as many coupling algorithms have been carried out, the research about coupling methods had been significantly advanced. In this paper, there are three methods, nearest neighbor interpolation, fast projection algorithm and interpolation scheme using radial basis function, respectively used in fluid-structure interaction of impeller, in order to derive coupling matrix. The derivation shows that the principle of nearest neighbor interpolation is very simple, and the mathematical concept of radial basis function is clear. Both are very conducive to program for calculation. Thus, corresponding procedures were established on platform of MATLAB. In addition, a internal function based on fast projection algorithm is contained in finite element analysis software ANSYS. By using this function, programming for fast projection algorithm were compiled in ANSYS-APDL script language.For the purpose of verifying the accuracy of the three algorithms above, a2D and3D interpolation example with analytic solutions was constructed respectively. Numerical results of these examples, which have been obtained from MATLAB or APDL procedures, were compared with analytic solutions to get the relative errors. These errors show that the RBF interpolation scheme is favored over the other two methods because of its high accuracy which is extremely meet the requirement of engineering application.It is noteworthy that, currently, researches about coupling algorithms for non-matching meshes were merely based on simple examples instead of complex fluid-structure models which always indicate some special difficulties such as complex interfaces, huge number of nodes and considerable computational effort and so on. For the widely application of interpolation algorithms in engineering, how to improve the computational efficiency under the premise of ensuring the accuracy becomes then far from trivial. Based on the partitioned coupling analysis of a impeller of centrifugal compressor, the procedure, compiled above, were developed by appending pre-processing and post-processing modules. What’s more, a simple and accurate approach which could greatly improve the computational efficiency were carried out to achieve data transfer. The set of data coupling method is able to apply in large fluid-structure interaction analysis, even in arbitrary field coupling analysis.This thesis is funded by The National Basic Research Program of China (Project2011CB706504) and Shenyang Blower Works Group Corporation.