In order to facilitate the application of special structural ejectors, which improve the ability of pumping the secondary flow without additional power consumption, reducing the flue gas temperature at the export and enhancing the ship viability under the threat of infrared guided weapons, this paper regardes the 90 ° bend tabs ejector as the research object according to the actual situation of our country’s ships, focuses on the inner effect of the existence of tabs on the flow field in the bent channel, and mainly revealed the transformation of the vortex around the tabs, for providing an explanation to a certain extent about how the tabs affect the macro performance of ejector. With ANSYS software, ring 8 equilateral triangles tabs were designed with 120 ° wall surface mounting angle. With adjusting the blocking ratio of the main outlet area based on the similar zoom, setting inlet swirl angle, and building a hybrid grid to compute, the vortex structure distribution and the development around tabs were observed. The maximum vorticity of vortex at different distances in the mixing tube to the mix tube exit had been calculated to reflect the change of vortex intensity. The final results show that although the streamwise vortices are still located in an axial symmetrical distribution, the swirl angle leads to an uneven distribution of the flow on both sides of a single tab. The inlet swirl angle can make the symmetry of the steamwise vortex vaguer, but the effect of the convection to the vortex is enhanced. The blocking area ratio of the nozzle cross-sectional surface has a large effect on the vorticity of the streamwise vortex. The calculation results show that the larger the blocking area is, the greater the vorticity of streamwise vortex is, which also shows that when the tab shape is fixed, the tab surface area will increase the streamwise vorticity. Through the above research, the shape and the change of the streamwise vortex generated by the tabs in the bent ejector are clearly demonstrated, which can be a reference for the design of high performance bent ejector.

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