| The internal flow characteristics of a rearward-loaded turbine cascade are studied in detail by means of experimental investigation and numerical simulation in this thesis. The analysis of secondary flow structures and loss mechanisms is presented.Firstly, the convergence and transition sections are designed with Morel method. Internal flow simulations for the convergence and transition sections are numerically carried out. The results show that the flow field comes to uniform at the outlet, and the average loss at the outlet section is very small. That means the convergence and transition sections can provide good aerodynamic performance for the inlet conditions of the testing cascade.Secondly, performance of a rearward-loaded cascade is experimentally studied at different Mach numbers on annular cascade test setup of wind tunnel. The pressure distributions on the profile of cascade blade are measured and also compared with the test and the calculation results of planar cascade, and it is indicated that the loss of secondary flow is small due to the special load distribution of the cascade. With this work, a set of experimental data that is important for farther research and numerical simulation is obtained.Finally, Numerical simulation for rearward-loaded cascades at different Mach numbers is conducted. The generation, structure development and losses of secondary flow with different Mach numbers are also analyzed. Results reveal that due to the special load distribution of the cascade, the generation of secondary flow is delayed and decreased efficiently, keeping underdeveloped before exit from the cascade.The obtained results of this thesis are of important academic value for the investigation on the internal flows of cascade, the formation and developing of secondary flow and the methods of reducing secondary flow losses. In addition, it is also of engineering and practical value for the design and optimization of rearward-loaded cascade of turbomachinery.
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