Parametric Expression Of Cooling Structure Of Turbine Blade And The Optimization Design Of Channels With Ribs

Turbine plays a decisive role in power and efficiency of gas turbines as one of core component of gas turbine unit. Increasing turbine inlet gas temperature is one of important means to improve turbine efficiency and increase thrust-weight ratio. Modern advanced gas turbines usually use combined cooling methods to enhance cooling effect of blade in order to increase turbine inlet temperature. Therefore, it's essential to quickly design to the advanced cooling structure meeting the requirements.This paper summarized the CFD numerical calculation and optimization design of turbine cooling structure, systematically reviewed optimization status at home and abroad. This paper presented a new optimization ideas of turbine blade cooling structure, achieved estalishment of optimization platform, namely, this platform can be summarized as the process of parametric modeling for cooling structure, automatic discreting grid, determining the optimization goal, selecting an appropriate optimization algorithm, using CFD calculation and analyzing the flow field, and optimized designing cooling structure. Thereby, ultimately presented a optimization design method of turbine blade cooling structure.Based on the optimization platform, aimed at rectangular and U-shaped channel with ribs, this paper carried out optimization calculation to geometric parameters (rib angle, rib spacing) to the effect of heat transfer performance and flow loss under different Re numbers taking maximum cooling efficiency and minimal flow loss as objective function, and analyzed of flow phenomenas and mechanisms in order to lay foundations for future optimization design.This paper showed optimization results with effect of geometry (rib angle, rib spacing) on the heat transfer performance and flow loss. Under the conditions of 10000 Reynolds number, when rib angle was 48.5°and ratio of the rib spacing to rib height was 6.17, rectangular channel had the best heat transfer performance; under the conditions of 30000 Reynolds number, when rib angle was 50.32°and ratio of the rib spacing to rib height was 7.53, rectangular channel had the best heat transfer performance; under different Reynolds number,when rib angle was 30°and ratio of the rib spacing to rib height was 6, rectangular channel have the best overall thermal performance. Under the conditions of 10000 Reynolds number,when rib angle was 46°, U-shaped channel had the best heat transfer performance,and when ratio of the rib spacing to rib height with ribs 6.18, U-shaped channel had the best overall thermal performance; under the conditions of 30000 Reynolds number, when rib angle with ribs 47°, U-shaped channel had the best heat transfer performance,and when ratio of the rib spacing to rib height was 11.1, U-shaped channel had the best overall thermal performance;under different Reynolds number, when rib angle was 30°, U-shaped channel had the best overall thermal performance, and ratio of the rib spacing to rib height was 14, U-shaped channel had the best thermal performance. For rectangular channel with ribs, optimization found slant ribs improved the effect of heat transfer by inducing lateral secondary flow between libs,and different rib angles had different effect on the secondary flow; different rib spacing effected separation and reattachment of the boundary layer, which lead to different effect of heat transfer; the smaller angle had the low flow loss. For U-shaped double process channel with ribs, elbow area induced a strong secondary flow, which made the heat transfer of elbow area and the upper reaches of the second process improve, and caused great flow loss; by analyzing, we knew, the second process with ribs would weaken elbow area effect on heat transfer of the second process, so the arrangement of ribs isn't proposed at second process.