为探究机动载荷引发的高压涡轮转子振动对凹槽叶尖气动和换热特性的影响,采用数值模拟方法对振动影响下无气冷和气冷凹槽叶尖的时均和瞬态气热性能进行对比分析。结果表明,振动对时均特性影响有限:无气冷叶尖振动工况下平均总压损失系数较无振动下降0.2%(由0.0946降至0.0944),面平均换热系数波动小于0.2%;气冷叶尖分别减小3.8%和0.8%。瞬态分析表明:无气冷叶尖的瞬时泄漏流量、面平均总压损失系数和换热系数均与振幅呈正相关,凹槽底面10-70%Cx及肩壁顶面10-60%Cx区域的换热系数对振幅变化敏感;气冷叶尖在冷气掺混与振动共同作用下,涡系强度增大,气动损失波动加剧,凹槽底面换热不均匀性增强;其中尾缘肩壁顶面换热系数受振动影响显著且冷气难以覆盖,在设计中应重点关注。
In order to explore the influence of high-pressure turbine rotor vibration caused by dynamic load on the aerodynamic and heat transfer characteristics of grooved tip, the time-averaged and transient aerodynamic and thermal performance of non-air-cooled and air-cooled grooved tip under the influence of vibration were compared and analyzed by numerical simulation method. The results show that the influence of vibration on the time-averaged characteristics is limited : the average total pressure loss coefficient under the condition of no air-cooled blade tip vibration is 0.2 % lower than that without vibration ( from 0.0946 to 0.0944 ), and the fluctuation of the surface average heat transfer coefficient is less than 0.2 %. The air-cooled blade tip decreases by 3.8 % and 0.8 %, respectively. The transient analysis shows that the instantaneous leakage flow rate, the surface average total pressure loss coefficient and the heat transfer coefficient of the air-cooled tip are positively correlated with the amplitude. The heat transfer coefficients of the 10-70 % Cx region on the bottom surface of the groove and the 10-60 % Cx region on the top surface of the shoulder wall are sensitive to the amplitude change. Under the combined action of cooling air mixing and vibration, the strength of the vortex system increases, the fluctuation of the aerodynamic loss increases, and the non-uniformity of the heat transfer at the bottom of the groove increases. Among them, the heat transfer coefficient of the top surface of the trailing edge shoulder wall is significantly affected by vibration and the cold air is difficult to cover, which should be paid attention to in the design.