Bullerdämpat utloppsmunstycke
Abstract
The project FMV projekt “Bullerdämpat utloppsmunstycke” will run during 2017 and into 2018. The project is a continuation of previous FMV project, in which Chalmers University of Technology (CTH), University of Cincinnati (UC), GKN Aerospace (former Volvo Aero) and the Royal Institute of Technology (KTH) participated. The objective of the project is to investigate means of reducing noise from a supersonic jet using micro-jet injection, both steady-state and pulsating, in a convergent-divergent nozzle for military low bypass ratio engines. The technologies will be studied experimentally and numerically. Other purposes are to look at optimization of the nozzle throat and system performance impact of the noise reduction technologies. In the previous project four types of nozzles were studied; a basic rotational symmetric nozzle, a chevron nozzle and a nozzle with micro-jet injections and an optimized nozzle. The nozzles were designed for a nozzle pressure ratio that is typical for low bypass ratio military engines at take-off and high altitude cruise. It was found that the chevron nozzle effectively reduced broad band mixing noise and that micro-jets reduce shock-induced noise, and that these two technologies complement each other. Moreover, the project will give insight into what mechanisms are active in these noise reduction technologies. In the current project noise reduction for non-circular nozzles will be investigated. The numerical results obtained will be compared with existing experimental data from the University of Cincinnati.
