Multi-objective design of laminated cooling configuration applied in gas turbine based on fuzzy grey relational analysis

Abstract

Laminated cooling is a compound system consisting of different cooling units that can provide effective protection to the hot components in next generation gas turbines. In the present work, using validated numerical simulations, the influential levels of geometrical parameters in laminated cooling configuration (film hole diameter, pin-fin diameter, impingement hole diameter and film hole inclined angle) on multi-objective functions (overall cooling effectiveness, friction loss and temperature uniformity) are calculated and ranked by fuzzy grey relational analysis (FGRA). The FGRA results indicate that the film hole diameter is the primary influence factor on the overall cooling effectiveness and temperature uniformity, but insensitive to the friction loss. Based on this finding, two novel laminated cooling configurations with revised film-hole shapes, i.e., fan-shaped film holes and discrete rectangular film slots, are proposed to meet the multi-objective requirement. Through calculations, it is proved that the overall cooling effectiveness of the discrete film slots with a width of 0.5 mm can be increased by approximately 20%, whereas the additional friction loss is negligible (the increase of flow resistance coefficient is only 0.06 at mass flow ratio equals to 1.19%). Meanwhile, the acceptable temperature uniformity along with high overall cooling effectiveness, low friction loss can be obtained with the design of the fan-shaped film holes. The present work provides a novel analytical method for the multi-influence-factor problem and multi-objective design of complex laminated cooling system in gas turbine application.