Impingement Jet Cooling System with Fluidic Oscillator

Abstract

This Study discusses an impingement jet cooling system for gas turbine applications that is enhanced by a fluidic oscillator. The reference configuration consists of a row of nine inline round jets with a diameter of 0.0152 m, a jet-to-plate spacing H/D = 5 and a jet pitch P/D = 5. A constant heat flux of 5,000 W/m² is applied to the target plate and the global jet Reynolds number is 10,000. Unsteady RANS simulations with the DLR in-house code TRACE and the k–ω SST turbulence model are used to study several configurations in which a sweeping-jet fluidic oscillator is placed either in the inlet channel, in the hole plate between jets 7 and 8, or on the target plate. The results show that the oscillator only moderately affects the global discharge coefficient but significantly modifies the local Nusselt number distribution and flow structures. The most promising configuration is obtained when the oscillator is mounted on the hole plate, where it stabilizes the downstream jet and mitigates cross-flow effects, leading to enhanced heat transfer near the stagnation region. Configurations with the oscillator on the target plate show a reduction of the area-averaged Nusselt number. Overall, the simulations of the first configuration show the best agreement with available PIV and heat transfer measurements and form a basis for future optimization and correlation development.