Research On Design Technology Of The Aspirated Compressor

In recent years the compressor technology of aviation engine advances very fast in the world, bings lighter weight to meet the requirement of lifting thrust/weight and lowering the cost. However, increasing the stage loading of the compressor causing the difficulties in the aerodynaic design, which needs some new ideas and new technologies to enable possible maintaining required high efficiency and wide opperability under increased stage loadings. The investigation of the aspirated compressor technology in this thesis includes:1. The work mechnism of the aspirated compressor was studied as the basis for development of the design system for the aspirated compressor. The design study of a single stage aspirated compressor with total pressure ratio of 2.5 under a moderate rotor tip speed with a practical compressor engineering background is conducted in order to set up the high aerodynamic loading, and to establish a basis for developing the qusi-3D inverse-problem method of the compressor airfoil and blade-to blade flow analysis method. In this thesis an emperism loss model was proposed for the meridional through flow calculation of the compressor, the qusi-3D inverse-problem airfoil design method worked out and a design procedure summarized. Finally a seris of the high efficient streamline airfoil design for the high loading aspirated compressor were completed.2. Supersonic/transonic cascade wind tunnel tests were implemented to study the effect of boundary layer suction on/off on the cascade airfoil surface velocity distribution and profile losses with the variation of incidence angle, inlet Mach number and the suctioned mass flow rate. In addition, the same test was also done under a off-design suction location with the purpose to investigate the effect of suction on the cascade performance under different suction location. The test shows the cascade airfoils designed achieve its design goal with higher flow turnning capability, lower losses contrasted to the case with no boundary suction. The study demonstrates the effectivty of the aspirated compressor idea and the feasibility of the design technology developed in this thesis.3. Besides, the numerical viscous flow solver NAPA is adapted to analyze the tested aspirated compressor cascade. The numerical analysis qualitatively reproduces the physical phenominae found in the cascade wind tunnel test, such as, the boundary layer suction has almost no influence on the cascade loss when the suction located in front of the shock impingement point on the airfoil suction side, and the Mach number increased behind the suction loction. However, very low suction mass flow brings the lower losses and increased flow turning when the suction is located in the separated region behind the shock, accompanying the phenomena of shock slightly moving backward and showing the stability enhancement under boundary layer aspirated. This provides a possible way to analyze correctly the flow field of the aspirated compressor.