Numerical Analysis of Scallop Shapes on Performance of Lobed Nozzle

Abstract

The infrared suppressor used in the exhaust system of turbofan engines, turbojet engines and turboprop engines generally has a lobed nozzle to pump cool air from the outside and mix it with the hot exhaust gas from the engine. The lobed nozzle mixes the primary and secondary streams with high effectiveness but induces low pressure loss has been widely used for heat and mass transfer in the fluid engineering field. The primary parameters used to evaluate the performances of the lobed nozzle include pumping performance, mixing effectiveness, and pressure loss. Higher pumping performance, higher mixing effectiveness, and lower pressure loss indicate that more cool air is pumped, the mixing with the hot exhaust is more effective, and there is less energy loss. The present study shows that double triangle scalloped nozzles has high mixing effectiveness than all other scalloped nozzles considered in the project work.