Papers by Author: Xi Yang

Abstract: This paper studies the aerodynamic and heat transfer influence of tip structures for cooling turbine blade. Four blades with different tip features are discussed, and coupling aerodynamic and heat transfer method is used to accomplish the simulation. The results show that squealer tip can greatly reduce the heat transfer between tip surface and high temperature gas, and also it reduces tip leakage, to some extent. That’s because it exists obviously eddy near the tip surface. Tip injection holes can cool the tip surface effectively, and it will greatly reduce the temperature of tip surface. However, injection holes improve tip leakage slightly.

Abstract: A numerical based study was conducted to further understanding of turbine tip leakage and flow mechanisms for squealer tip blade. Three blade geometry models with different tips are established. They are squealer tip blade, squealer tip with injection holes blade, squealer tip with injection and film cooling holes blade, separately. Coupled aerodynamic and heat transfer numerical simulation method is used to study blade tip flow and heat transfer based the whole blade computational model. The results show that tip coolant injection will perform a positive effect for the resisting tip leakage, and it will reduce the temperature of blade tip surface and squealer rim, greatly. Film cooling near tip can cool blade squealer rim effectively, but it brings extra total pressure loss.

Abstract: This paper presents an uncertainty propagation analysis method using the Convex Model Theory (CM) for turbine cooling blade multidisciplinary design. Convex Model is used to describe the design variables’ uncertainty, and it’s propagation equation is derived. Monte-Carlo(MC) method and Convex Model Theory (CM) are all employed to calculate target variable’s variation. Result shows that CM method is more time-saving than MC method. First order second moment method is employed to calculate the reliability of target variable’s variation to evaluate the difference of the results of the two methods. As the actual probability density function of design variables is unknown, so reliability analysis considers different probability density functions. Response surface method is used to construct the approximation of the multidisciplinary analysis. Reliability analysis result shows that CM method keeps the same accuracy with MC method.