This study proposes an efficient gas turbine blade aerothermal performance uncertainty system based on the genetic algorithm acceleration strategy, and develops a method for uncertainty data analysis of the blade tip aerothermal properties. The proposed system and method are utilized for the quantitative study of the uncertainty in the aerothermal performance of a squealer tip with film cooling structure, taking into account the operating condition fluctuation and geometrical parameter deviation. The results show that coolant jet injection will enhance the unsteady tendency of the downstream flow field of the first-stage rotor blades. In the actual operation of the gas turbine, the film cooling effectiveness in the region predicted at the design stage to be adequately covered by the coolant jet will be much lower than the value obtained from the deterministic calculations. Under the impact of the uncertainty inputs, the film cooling effectiveness of the squealer tip meets the Normal distribution. The mean value is reduced by 20.06% compared with the design value, and the probability of 10% deviation from the design value is as high as 81.84%. The result of sensitivity analysis shows that the main parameter affecting the fluctuation of the total downstream pressure loss coefficient is the tip clearance deviation, with the variance index as high as 87.21%. The total inlet temperature fluctuation is the key parameter affecting the uncertainty of the film cooling effectiveness, with the variance index of 84.01%.

Less leakage is a benefit of parallel grooved liquid seals (labyrinth seals). But researches show that the liquid seal with parallel grooves on the rotor harms the rotor stability. The seal with helical grooves on stator performs well in terms of rotordynamics, and its leakage is sensitive to the rotating speed. To make use of the advantages of both seals and improve seal stability, based on the Smooth-stator/Parallel Grooved-rotor (SPG) liquid seal, a Helical Grooved-stator/Parallel Grooved-rotor (HGPG) liquid seal is designed. To evaluate two liquid seals’ leakage, rotordynamic characteristics and drag power loss, a transient computational fluid dynamics-based method is employed. This method is based on the multi-frequency elliptical-orbit rotor whirling model and the mesh deformation technique. The published experimental data of the leakage and rotordynamic force coefficients for an SPG liquid seal are used to validate the accuracy and dependability of the current method. Seal leakage and force coefficients are presented and compared for the SPG liquid seal and the HGPG liquid seal at various pressure drops. The influences of parallel groove depth on the leakage and rotordynamic properties for the HGPG liquid seals at two rotational speeds (2000, 6000 r/min) are analyzed. The numerical findings demonstrate that the novel HGPG liquid seal has a lower leakage flow rate (by ~22.3%) than the traditional SPG liquid seal. There is an optimal parallel groove depth that minimizes leakage. The presented novel HGPG liquid seal significantly improves rotordynamic stability, due to the similar effective stiffness and the obviously larger positive effective damping. Reducing parallel groove depth can increase the positive effective damping. In terms of leakage and rotordynamic characteristics, the novel HGPG liquid seal is a better seal design for liquid turbomachinery.