CFD based study of unconventional aeroengine exhaust systems
conference contributionposted on 30.08.2012 by Tim Coates, Gary J. Page
Any type of content contributed to an academic conference, such as papers, presentations, lectures or proceedings.
The effect of upstream duct curvature on the exhaust plume of a jet engine is cur- rently undocumented. Here, three different upstream curvatures are simulated using CFD to investigate the effect of upstream duct curvature on the over-expanded exhaust plume emanating from a rectangular nozzle of aspect ratio 5.8:1 at a nozzle pressure ratio of 2.5 and Reynolds number of 7.61 × 105. Due to the lack of available experimental data for curved ducts connected to high speed jets, the initial work was to validate the methodol- ogy for separate S-bend and rectangular nozzle high speed jet cases. These showed that RANS methods were poor for predicting secondary flows in the S-bend and for predicting mixing and potential core length in the rectangular jet. However, LES did show signifi- cant improvements for the rectangular jet and correctly predicts the shear layer mixing. Calculations were carried out using an unstructured, median-dual CFD solver with pre- dominantly hexahedral elements containing approximately 65.5−67.5 million nodes. For the combined S-bend and nozzle cases it was seen that increasing upstream duct curvature re- duces the potential core length and increases losses in the upstream duct. Transverse total pressure gradients were also observed at the nozzle exit plane in both k-ǫ and WALE LES turbulence models, however to a significantly smaller degree in the latter. The upstream duct curvature was also seen to have an impact on the shock cell development, altering both number and location.
- Aeronautical, Automotive, Chemical and Materials Engineering
- Aeronautical and Automotive Engineering