Study on Compound Impingement Cooling Characteristics of Ring Segment Components in a Heavy-duty Gas Turbine

With the continual rise in turbine inlet temperatures of heavy-duty gas turbines, conventional impingement cooling techniques are increasingly inadequate to meet the growing cooling demands of high-temperature turbine components. Focusing on turbine ring segment components, four combined impingement cooling unit configurations based on traditional impingement cooling structures by incorporating various turbulence-enhancing structures on the target surface were proposed. And they were applied to cooling scheme for ring segment components. The semi-coupled numerical simulation method was used to study the comprehensive cooling characteristics of each scheme under the operating conditions of F-class, G/H-class, and HL-class gas turbines. The results demonstrate that applying discrete turbulence-enhancing structures on the target surface increases heat flux by 13.1%-17.6%. Among these configurations, the pin-fin with dimpled surface (PF) configuration exhibits the optimal cooling performance. Under the operating conditions of H-class, the cooling effectiveness of the ring segment scheme utilizing combined cooling units is improved by 3.3%-9.3%, with a more pronounced enhancement under high Biot number conditions (e.g., HL-class), reaching a maximum improvement of 10.1%. The discharge coefficient of the combined scheme is reduced by 1.2%-7.5%. Compared with traditional approaches, the proposed method has more advantages when applied to the high-temperature components of the turbine in the next-generation autonomous gas turbine products.