Flow loss assessment for a supercritical carbon dioxide axial turbine stage
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.
carbon dioxideturbine stageentropy generation rateflow loss
国家科技期刊平台
NSTL
万方数据
维普
