轮缘封严气流与转子干涉损失机理的数值研究

In order to investigate the interaction and loss mechanisms between turbine stator-rotor cavity rim seal flow and downstream rotor, numerical investigations were conducted for effects of rim seal flow on the aerodynamic performance and flow field of rotor at different rim seal flow rate. The results show that with the increase of rim seal flow rate, the stage efficiency keeps on decreasing. In addition, the mass flow coefficient increases in the region from hub to 10% span and from 30% to 60% span. The rim seal flow mainly influences the rotor performance by the different distributions of egress flow at rotor inlet and interaction with secondary flow in rotor passage. Besides, there are three loss factors related to the decreasing of rotor performance caused by rim seal flow. One is the viscous shear loss caused by increasing circumferential velocity difference between the rim seal flow and mainstream. The increasing circumferential velocity difference results from the reducing pump effect of the rotational disc with the increment of rim seal flow rate. Second is the blockage effects and negative incidence angle caused by egress flow lead to decreasing work. The last one is the interaction in transportation process between different egress flow and secondary flow in rotor passage results in increasing secondary loss.