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

This research focuses on optimizing the cooling system of a circular-to-rectangular transition duct in a turbine engine nozzle, a critical step in enhancing engine efficiency by enabling higher turbine inlet temperatures and increased thrust through afterburner usage, both of which significantly elevate exhaust gas temperatures. the study employs a combined film and impingement cooling method and utilizes fluent computational fluid dynamics software for analysis and optimization. experimental design methodology was used to identify key parameters for optimizing the geometry for three blowing ratios (0.5, 1, and 1.5). simulation results demonstrate that the optimal cooling configuration for all blowing ratios includes three rows of film cooling. the most influential parameters on cooling efficiency were found to be the diameter of the film cooling holes and the number of film cooling rows. for a blowing ratio of 1.5, increasing the hole diameter and the number of cooling rows resulted in a 32% and 33% increase in cooling efficiency, respectively. regarding the relationship between cooling angle and efficiency, it was observed that efficiency increased up to 20 degrees and then decreased in blowing ratios of 0.5 and 1.5, while in a blowing ratio of 1, efficiency increased up to 30 degrees and then decreased. this research provides valuable insights into optimizing the cooling system of turbine engine nozzles, enabling more efficient and powerful engines.