| In order to improve the performance of gas turbine, it is important to research transonic and supersonic compressors. As a new type of supersonic compressor rotor, Ram-rotor utilizes shock waves to compress air, whose pressure ratio is higher, structure is more simple, and size is smaller than conventional compressor. In order to improve the overall performance and obtain the structure of flow field with different hub and strake configuration, numerical method was used to research ram-rotor’s flow field whose hub and strake configuration are obtained by different ways.Firstly, the ram-rotor with different hub configurations is obtained by changing the shape of compression ramp and diffuser surface along flow direction, controlling the partial shape of hub. Three dimensional flow fields of the ram-rotor is simulated numerically then. It has been found that the structure of shock wave is changed as the shape of compression ramp is changed. The ram-rotor’s loss is decreased by changing the compression ramp so as to generate series of shock wave. But changing the shape of compression ramp can not improve the overall performance of ram-rotor obviously according to ram-rotor’s characteristic of flow structure. Changing the shape of diffuser surface can affect the performance of ram-rotor. As the decrease of initial diffuser angle, the performance of the ram-rotor is improved slightly. The total pressure ratio of the ram-rotor will increase with the length increasing of isolation section. The ram-rotor has higher efficiency and total pressure recovery coefficient when diffuser surface is longer. Changing the partial shape of hub can not affect ram-rotor’s performance obviously.Secondly, the ram-rotor with different strake configurations is obtained by changing the shape of strake forepart, strake backpart. Then the numerical study is conducted to investigate the influence of different strake configurations. The results show that changing the shape of strake forepart has a positive influence on ram-rotor by changing strake leading shock. The structure of ram-rotor’s leading shock can affect the inlet flow rate and quality, and can also increase the pressure ratio and reduce the flow loss in ram-rotor’s path. Changing the shape of strake backpart has a great effect on the flow structure near outlet of left strake. As the start point of trailing edge move backward, the flow structure of each case get better, but there is a best position of the start point, continue to move backward will affect the total pressure ratio of the ram-rotor because of the expanding near outlet of right strake. In addition, increasing compression angle of the strake’s backpart can also get good performance. Taking strake strength into account, the best case is obtained by changing the strake configuration including the shape of forepart and backpart. |
PDF Full Text Request