Modeling And Analysis Of Three-dimensional Steady Vortex Structure In Axial Compressor

The development of gas turbine has put further demands on the aerodynamic performance of compressor component. The flow in compressor is one of the most complex flow phenomena in engineering. Main character of the flow is the complex vortex system. The formation, development and breakdown of vortex, the interaction between vortex and main flow and the interactions among vortexes dominate the elementary characters of the flow and the force on the bodies. Since the vortex structure has direct impact on the energy loss distribution, efficiency and stability of the compressor, it is of high value to study the inner vortex structure and loss increase mechanism inside compressor passage.Firstly, a detailed low speed wind tunnel experiment has been carried out about one large turning angle, high load rectangle compressor cascade. The flow field information of the flow passage outlet cross sections is obtained by using L-shape five holes probe at three incidence angles in this experiment and the vortex structure plots in the cross sections are obtained. Then, numerical simulation is done to make up more details about the experimental results.The experiment indicates that there are two passage vortexes in cascade passage at three incidence angles. At-6and0degree incidence angle, the flow condition is good and stable while two concentrated shed vortexes exist in the middle of passage. At+6degree incidence angle, the separation zone appears in the whole span of the blade and total energy loss increase dramatically. Then, the numerical results are analyzed and the evolution laws of passage vortex, concentrated shed vortex and corner vortex are obtained. With the increase of inlet incidence angle, the original location of the passage vortex moves forward.Secondly, the vortex structure of transonic compressor stage is discovered based on former researches. Thirteen working conditions of the compressor stage are calculated at the design rotational speed and the compressor characteristic curves are obtained. Due to numerical results, in design condition, the flow condition is good. In near stall condition, flow separation occurs in the upper part of the stator blade and the shroud. In near choke condition, flow separation occurs in the bottom part of the statot blade and the hub.Since the streamline plots in different cross sections cannot show the vortex development clearly in compressor stage, another calculation method of secondary flow is studied. Then, the vortex structure of the stator passage in design condition, neat choke condition and near stall condition are analyzed by studying the vortex development in different cross sections along the stator passage. In design condition, upper passage vortex, upper concentrated shed vortex and passage vortex derivative vortex exist in the passage; in near choke condition, pressure side lead edge separation vortex, suction side-hub corner separation vortex and upper concentrated shed vortex exist in the passage; in near stall condition, suction side separation vortex exists in the passage.