Heat transfer characteristics of triple-stage impingement designs and their application for industrial gas turbine combustor liner cooling

Abstract

This paper reports a triple-stage impingement concept with two optimized designs to tackle the common design challenges of the adverse effect of cross flow and coolant maldistribution on impingement cooling for modern gas turbine components. Flow structure and heat transfer characteristics were investigated at two different constant uniform wall temperatures with lower wall temperature related to lower wall to jet temperature ratio and the higher wall temperature related to higher wall to jet temperature ratio. The feasibility of application the triple-stage impingement cooling designs to a gas turbine combustor liner was conducted through Conjugate Heat Transfer analysis by applying a wall with realistic material thermal properties at two different constant wall heat fluxes. All studies were carried out at engine operation conditions with high air pressure and temperature. The results show that the triple-stage impingement cooling designs can reinitiate impingement jets at each stage, which greatly reduces the cross flow impact and local thermal gradient. The staging of cooling air for combustor cooling also offers better utilization of the cooling capacity. Even with 50% reduction in the cooling air consumption compared to conventional single-stage impingement design, both triple-stage impingement designs can still sufficiently cool the combustor liner. Both triple-stage impingement designs can be practically applied to gas turbine combustor liner cooling.