Numerical Investigation of the Effects of the Hole Inclination Angle and Blowing Ratio on the Characteristics of Cooling and Stress in an Impingement/Effusion Cooling System

Abstract

Due to the uneven temperature field and temperature gradient introduced by an efficient cooling structure, the analysis of the stress field is necessary. In this study, the cooling characteristics and stress characteristics such as the thermal stress and thermomechanical stress of an impingement/effusion cooling system were investigated by employing a fluid–thermal-structure coupling simulation method. The effects of film hole injection angle (30°–90°) and blowing ratio (0.5–2.0) were studied. The results showed that the film hole shape and the non-uniform temperature field introduced by the cooling structure had a great influence on the stress field distribution. With the increase in the blowing ratio, not only the overall cooling effectiveness of the cooling system increased, but the maximum thermal stress and thermomechanical stress near film holes also increased. The cases with a smaller inclination angle could provide a better cooling performance, but caused a more serious stress concentration of the film hole. However, the thermal stress difference at the leading and trailing edges of the film hole increased with a decreasing inclination angle. The cases with a = 30° and 45° showed serious thermal stress concentration near the hole’s acute region.

Keywords

• impingement/effusion cooling
• inclination angle
• blowing ratio
• conjugated heat transfer
• stress