In order to further investigate the loss mechanism in supercritical carbon dioxide turbines

the flow characteristics in a turbine stage were studied by numerical method. The losses in the passage of stator and rotor blades were decomposed

and the various loss values and their proportions were quantitatively calculated. The loss sequence of the supercritical carbon dioxide turbine stage was clarified. The results show that

the high density of supercritical carbon dioxide and low blade height result in a very large leakage loss in turbine stage. When the stage load coefficient is 0.93

the relative height of the stator clearance is 0.012 and the relative height of the rotor clearance is 0.010

the leakage loss accounts for 38.23% of the total loss

including 21.94% of the diaphragm seal leakage loss and 16.29% of the tip seal leakage loss. Except for leakage loss

when the average maximum thickness divided by chord length is 0.33 and the aspect ratio is 2.07 in stator passage

the profile loss is much higher than the endwall loss and trailing edge loss

accounting for 9.68% of the total loss. In rotor passage

when the average maximum thickness divided by chord length is 0.28 and the aspect ratio is 1.73

the difference among endwall loss

profile loss

and trailing edge loss is not significant

and the profile loss has the highest proportion

accounting for 15.39% of the total loss. The influence range of secondary flow in rotor is even wider

and its endwall loss is much higher than that of the stator. The main sources of endwall loss are viscous dissipation of fluid near the end wall and secondary loss caused by horseshoe vortices

passage vortices

etc. The research results will provide direction guidance and data support for the design and optimization of supercritical carbon dioxide turbines.