Flow Development through HP ＆ LP Turbines, Part I： Inward Rotating Cavity Flow with Superimposed Throughflow

• Published in: Journal of thermal science Vol. 26; no. 4; pp. 297 - 307
• Main Authors: Gao, Jinhai, Du, Qiang, Liu, Jun, Liu, Guang, Wang, Pei, Liu, Hongrui, Du, Meimei
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.08.2017; Springer Nature B.V
• Subjects: Boundary layer; Cavity flow; Classical and Continuum Physics; Computational fluid dynamics; Computer simulation; Engine design; Engineering Fluid Dynamics; Engineering Thermodynamics; Fluid flow; Heat and Mass Transfer; Inviscid flow; Mathematical models; Numerical analysis; Physics; Physics and Astronomy; Pressure loss; Turbines; Vortices; Walls; 低压涡轮; 内旋转; 压力损失; 发动机设计; 叠加; 损耗机理; 无粘流动; 涡流比; Superimposed throughflow; Flow pattern; Turbines; Inward rotating cavity flow
• ISSN: 1003-2169; 1993-033X
• DOI: 10.1007/s11630-017-0942-7

With the aid of numerical method, both flow field and its accompanied loss mechanism within the rotating cavity are investigated in detail in the 1st part of the two parts paper. For ease of comparison, rotating cavity is further classified as the rotor-stator cavity case and the rotor-rotor cavity case. Results indicate that flow within both kinds of the cavity act as the inviscid flow except that the flow near walls, neighboring the lower G region and in the vicinity of the rotating orifices. In the regions except such inviscid-flow-dominate domains, the theoretical core rotation factor can be safely used to predict the swirl ratio within the cavity. When detailed flow pattern is considered, Ekman-type flow exists near periphery of the surface＇s boundary layer where viscous effect is non-negligible. However, due to the complex profile of the simulated cavity case, vortices structure is varied within the cavity. By comparison, swirl ratio can be used to predict the magnitude of loss. Due to the relatively evident rotating effects of the rotor-rotor cavity, swirl ratio even increases to 1.4 in the current model, which means that flow is moving faster than the surrounding disc. Further investigation finds that this kind of highly ro- tating flow is accompanied with serious undesirable pressure loss. Parenthetically, unlike its counterpart, swirl ra- tio above 1.0 doesn＇t happen when fluid passes through the rotor-stator cavity. So it is suggested that rotor-rotor flow cavity with the superimposed inward throughflow should be avoided in the engine design or certain mea- surements should be provided when such structure design is unavoidable. Simulation done in the current paper is meaningful since these dimensional parameters are typical in the design of state-of-art. Relatively lower range of Re~ and Cw is not considered in the current two parts paper.