The Flow Simulation In The Compressor With The Effect Of Fluid-Solid Interaction

The development of aeroengine with a large thrust-weight ratio requires its main part---compressor to have a high aerodynamic performance. In order to obtain a compressor with a higher efficiency, a larger surge margin and a lower weight, the highly-loaded compressor with a less stage numbers becomes necessary. For the purpose of reducing the R&D costs, it is an important method to design the compressor using the advanced CFD technology. How to simulates the compressor characteristics and its internal flow accurately becomes the key technology.Compressor blades with a high load runing under a high rotating speed, are exposed to a large aerodynamic and inertial force. In the case of interaction of these forces, the fan blade has a large deformation. Deformation can result in a great variation of aerodynamic parameters, including inlet flow angle and entrance area of flow passage and so on, which leads to the variation of the aerodynamic performance of the compressor. The balde deformation therefore must be considered in the numerical simulation of compressor internal flow. Since the deformation is closely related to the aerodynamic force, this simulation is a process which is coupled by the fluid mechanics and the solid mechanics.In this paper, the flow-structure coupled numerical simulation was carried out via CFD and CDS technology to study the internal flow of a transonic fan in turbofan engine. The DS module of ANSYS Workbench platform and APDL language were used as the interface which is adopted to transfer the blade surface load data. The nemerical result was compared with the experimental one.The result shows that there is a big difference between the numerical and experimental data without taking the fan deformation into account, thus the numerical simulation can not reflect the real condition of the fan flow field. The flow-structure coupled numerical simulation is able to reveal the fact that the main loss in the fan stage comes from the shock wave in the rotor and corner stall in the stator hub region. When the rotating speed is equal to or less than the rated one, the more accurate fan characteristics can be obtained, while the numerical fan characteristics is far from the experimental values when the rotating speed is greater than rated one, though the trend is almost the same bentween the numerical and experimental data. Fan surge margin obtained by numerical simulation is a little different from the experimental one, which infers that the simulation of surger margin maintains at a higher level. The study shows that there exists a double shock wave structure at rotor tip region. Under a high rotating speed, the shock in the flow passage becomes a normal one, resulting in a higher shock loss. Under a low rotating speed, the shock in the flow passage is not obvious while the detached shock is also weak in front of blade leading edge, thus the loss is lower than that in the casing of high rotating speed.From the radial distribution of the aerodynamic parameters at the exit of the fan stage, it can been seen that the curved stator is favorable to control the flow separation, therefore the distribution of the aerodynamic parameters is uniform in the radial direction, which is beneficial to the aerodynamic performance enhancement in the multi-stage compressor.