aerospace-05-00035.pdf (58.14 MB)
Download file

Influence of nozzle exit conditions on the near-field development of high subsonic and underexpanded axisymmetric jets

Download (58.14 MB)
journal contribution
posted on 30.01.2019, 10:24 authored by Miles T. Trumper, Parviz Behrouzi, James J. McGuirk
Detailed knowledge of jet plume development in the near-field (the first 10–15 nozzle exit diameters for a round jet) is important in aero-engine propulsion system design, e.g., for jet noise and plume infrared (IR) signature assessment. Nozzle exit Mach numbers are often high subsonic but improperly expanded (e.g., shock-containing) plumes also occur; high Reynolds numbers (O (106)) are typical. The near-field is obviously influenced by nozzle exit conditions (velocity/turbulence profiles) so knowledge of exit boundary layer characteristics is desirable. Therefore, an experimental study was carried out to provide detailed data on nozzle inlet and exit conditions and near-field development for convergent round nozzles operated at Nozzle Pressure Ratios (NPRs) corresponding to high subsonic and supersonic (underexpanded) jet plumes. Both pneumatic probe and Laser Doppler Anemometry (LDA) measurements were made. The data revealed that internal nozzle acceleration led to a dramatic reduction in wall boundary layer thickness and a more laminar-like profile shape. The addition of a parallel wall extension to the end of the nozzle allowed the boundary layer to return to a turbulent state, increasing its thickness, and removing vena contracta effects. Differences in nozzle exit boundary layers exerted a noticeable influence but only in the first few diameters of plume development. The addition of the exit extension removed the vena contracta effects of the convergence only design. At underexpanded NPRs, this change to nozzle geometry modified the shock cell pattern and shortened the potential core length of the jet.

Funding

Financial support for this project was received from EPSRC (Grant Number GR/02300852) and from BAE SYSTEMS (Warton, Lancashire, UK).

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Aeronautical and Automotive Engineering

Published in

Aerospace

Volume

5

Issue

2

Pages

35 - 35

Citation

TRUMPER, M.T., BEHROUZI, P. and MCGUIRK, J.J., 2018. Influence of nozzle exit conditions on the near-field development of high subsonic and underexpanded axisymmetric jets. Aerospace, 5 (2), 35.

Publisher

MDPI AG © The authors

Version

VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/

Publication date

2018

Notes

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

eISSN

2226-4310

Language

en