Implicit High Order Accuracy And High Resolution Numerical Simulation For Internal Flow Of Multistage Axial Flow Tubromachinery

To improve the numerical simulation technique for internal flow of multistage axial flow turbomachinery, several key problems in this area arc researched and developed in this paper.Equations in form of tensor for describing fluid dynamics are presented, which are free of coordinates. Equations in relative cylindrical coordinate system are educed by introducing orthotropic curvilinear coordinate system and Lame coefficient, and then projected to the computational space. The uniform expressions of flux vector after splitting are presented to simplify the computation procedure and make preparations to use the advanced finite difference schemes.Principles for constructing advanced finite difference schemes are analyzed. Then using high resolution three-order ENN scheme for simulating 3D turbulent flow in blade rows, applying LU-SGS implicit method to avoid calculating inverse matrix, the accuracy and efficiency of numerical simulating for complex flow in blade rows can be gained preferable effect.Two qualifications of treatment for rotor-stator interferential surface are discussed by consulting "mixing-plane method" , one is conservativeness of flow parameters in the interferential surface and the other one is cross-transmit of flow parameters between upstream section and downstream section. Based on these two qualifications, two classes of treatment model for rotor-stator interferential surface are presented, one is treatment based on the joined grid between rotor and stator, the other one is treatment based on the overlapped grid between rotor and stator. The validity of these two classes of treatment model is demonstrated by analyzing the numerical simulation results of two examples.Some typical problems which should pay more attention to in grid generation are discussed, a series of grid generation methods are presented by aiming at the features of research object in this paper. A set of grid generation software is developed by using Visual C++ computer language, it can generate H type grid in plane blade row and 3D blade row. The interface of this software has many control parameters, so it can generategrid fleetly and efficiently.Base'd on the above research, a numerical simulation system for internal flow of multistage axial flow tubromachinery is developed according to the serial partitioning algorithm presented in this paper. The validity of this system is demonstrated by numerical simulation of a two stages fan in near design condition and a three stages axial flow compressor with IGV at design rotating speed. The numerical results show that the numerical method developed in this paper has better resolution and definite accuracy and the dependability of the grid generation software is also testified.The work of this paper can be used in further research and development of high order accuracy and high resolution schemes as well as treatment for rotor-stator interferential surface, it also make some contributions for the numerical simulation of multistage axial flow turobmachinery and have better theoretic value as also broad technical application foreground.