Optimization of cooling system of circular to rectangular transition duct in a turbine engine nozzle

The use of afterburner in turbine engines increases the temperature of the exhaust nozzle, and this temperature increase necessitates the cooling of the nozzle components. This research discusses the analysis and optimization of the cooling system for the circular-to-rectangular transition duct at the inlet of the nozzle, utilizing a combined film and impingement cooling method. To more accurately achieve the optimal geometric model for three blowing ratios of 0.5, 1, and 1.5, effective parameters have been identified using the experimental design method. The simulation results indicate that the optimized geometries for all three blowing ratios of 0.5, 1, and 1.5 feature three rows of film cooling. Also, the two parameters of the film cooling hole diameter and the number of film cooling rows have the greatest effect on increasing the cooling efficiency. In the Blowing ratio of 1.5, by increasing the diameter of the film cooling holes and the number of cooling rows, the cooling efficiency has increased by 32 and 33%, respectively. Also, in the Blowing ratio of 0.5 and 1.5 blowing, the cooling efficiency increased from 0 to 20 degrees, and the cooling efficiency decreased from about 20 degrees onwards. In the blowing ratio of 1, the cooling efficiency increased from 0 to 30 degrees, and the cooling efficiency decreased from about 30 degrees onwards.