The Aerodynamic Research On The Serrated Trailing Edge Of Blade

As the main part of the aero turbine engine, the performance of the fan/compressor is steadily increasing, which mainly shows that the pressure ratio of single stage, the total pressure ratio and the efficiency become even higher. With the continuous improvement of the stage load of the fan/compressor, it puts forward more stringent requirements on the stability of the fan/compressor.Therefore, if the stability of the fan/compressor could be enhanced, the pressure ratio of fan/compressor can be effectively improved, which makes it possible to develop a more efficient and high load fan/compressor.Due to the blade wake effects on the transient incident angle of downstream blade and suction surface boundary layer of downstream blade, thus affecting the compressor stability, serrated trailing edge of blade that through the reasonable organization of the wake to improve the compressor stability for enhancing the fan / compressor stability is proposed. It is based of the entrainment of serrated flow vortex tube to the main stream and the interaction of longitudinal vortex and shear layer of the flow wake.In this paper, the effect of the serrated trailing edge blade on the performance of the planar cascade is studied. On the specific form of the trailing edge of the blade, the paper studies three kinds of the trailing edge shape: triangular, trapezoidal and circular.In this paper, The pattern and main modes of inherently unsteady wake flow of serrated trailing edge blade were numerical analyzed by Computation Fluid Dynamics. Four kinds of blade(triangular, trapezoidal, circular serrated trailing edge and the baseline blade) have been studied systematically. Moreover, the flow characteristics of triangular serrated trailing edge blade and baseline blade have been tested in planar cascade wind tunnel test rigs.Through the study of Computation Fluid Dynamics and the experiment, the result shows that three kinds of serrated trailing edge of blades can effectively reduce the total pressure loss, which bring on the compressor efficiency. But it also shows that the turning angle of three kinds of serrated trailing edge of blades are less than the baseline blade. So three kinds of serrated trailing edge of blades would reduce the work ability of the blade on airflow. Serrated trailing edge of blade can restrain the formation and development of the vortex above the blade surface,and the distribution of each parameter in the blade wake is more uniform.Three kinds of serrated trailing edge of blade can effectively improve the blade flow wake forms, strengthen the mixing between wake and the mainstream, reduce the wake loss. Moreover, the performance of triangular shaped serrated trailing edge blade is the best. It is expected that serrated trailing edge blade can effectively reduce the upstream blade wake negative impact on the downstream blade flow and delay the occurrence of compressor rotating stall, thus it can be used to broaden the compressor surge margin.