Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-26T23:07:18.795Z Has data issue: false hasContentIssue false
  • English
  • Français

Infrared signal of the lobed mixer with external air mixing

Published online by Cambridge University Press:  06 May 2021

S.M. Choi Open the ORCID record for S.M. Choi [Opens in a new window] ,
H.S. Jang  and
H.H. Park
S.M. Choi*
Affiliation:
Jeonbuk National University College of Engineering, Deokjin-Gu, Jeonju, Republic of Korea
H.S. Jang
Affiliation:
Jeonbuk National University College of Engineering, Deokjin-Gu, Jeonju, Republic of Korea
H.H. Park
Affiliation:
Hanwha Aerospace, Seongnam, Republic of Korea
*
csman@jbnu.ac.kr
Get access Rights & Permissions [Opens in a new window]

Abstract

In order to know the characteristics of reducing the exhaust gas infrared signal of the lobed mixer according to the external air mixing ratio, an infrared signal and temperature distribution measurement using a micro-turbojet engine is performed. A certain amount of compressed air is supplied through an external duct mounted on the micro-turbojet engine exhaust to simulate bypass flow, which is mixed with high-temperature core air and ejected to the atmosphere. The exhaust nozzle used in the experiment is a lobed mixer with a lobe of sinusoidal shape and is designed to have a penetration of 0.2. Exhaust gas temperature and infrared signal are measured according to distance from nozzle outlet under conditions of bypass ratio of 0.5, 1.0 and 1.4. Infrared reduction rates are compared to data without compressed air supply. As a result of the experiment, as the bypass ratio increased, the infrared signal of the exhaust gas and the temperature decrease with bypass ratio increase, and in the case of a bypass ratio of 1.4, the effect of reducing the temperature is observed even at a long distance. In addition, we compared the results of previous studies of a simple cone shape without mixer with infrared reduction effect. The results show that the lobed mixer has a greater effect on reducing the temperature of the exhaust gas and reducing the infrared signal than the cone nozzle. The structure of the mixed jet flow is also studied through Schlieren visualisation and 3D temperature distribution.

Keywords

micro-turbo jet enginelobed mixerbypass ratioinfrared signalexhaust gas temperatureSchlieren visualization
Type
Research Article
Information
The Aeronautical Journal , Volume 125 , Issue 1291: The 25th ISABE Conference Special Issue – Part I , September 2021 , pp. 1501 - 1518
Check for updates
Copyright
© The Author(s), 2021. Published by Cambridge University Press on behalf of Royal Aeronautical Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Baranwal, N. and Mahulikar, S.P. Review of Infrared signature suppression systems using optical blocking method, Defence Technology, 2019, 15, (3), pp 432–439.CrossRefGoogle Scholar
Mahulikar, S.P., Sonawane, H.R. and Rao, G.A. Infrared signature studies of aerospace vehicles, Prog Aerosp Sci, 2007, 43, (7–8), pp 218–245.CrossRefGoogle Scholar
Joo, M.L., Choi, S.M. and Jo, H.N. Status and characteristics of unmanned aerial vehicle gas turbine engines, J Korean Soc Prop Eng, 2020, 24, (2), pp 61–72.Google Scholar
Joo, M.L., Jo, S.P, Choi, S.M. and Jo, H.N. An experimental study of the infrared signal for exhaust plume with bypass ratio, J Korean Soc Prop Eng, 2019, 23, (5), pp 1–9.Google Scholar
Decher, R. Infrared emission from turbofans with high aspect ratio nozzle, J Prop Power, 2004, 20, (3), pp 527–532.Google Scholar
Rao, G.A., Buijtenen, J.P. and Mahulikar, S.P. The effect bypass ratio on aircraft plume infrared signature, International Symposium on Air Breathing Engines, vol. 2, 2009.Google Scholar
Khalid, S.J. Aerothermodynamic benefits of mixed exhaust turbofans, Fluid Mech Res Int J, 2017, 2.CrossRefGoogle Scholar
Mengle, V.G. and Dalton, W.N. Lobed mixer design for noise suppression, NASA/CR-2002-210823/VOL1, 2002.Google Scholar
Sheng, Z.Q., Liu, J.Y., Yao, Y. and Xu, Y.H. Mechanisms of lobed jet mixing: about circularly alternating-lobe mixers, Aerospace Science and Technology, 2019.CrossRefGoogle Scholar
Shan, Y. and Zhang, J.Z. Numerical investigation of flow mixture enhancement and infrared radiation shield by lobed forced mixer, Appl Therm Eng, 2009, 29, pp 3687–3695.CrossRefGoogle Scholar
Nam, J.Y., Bae, J.Y., Bea, H.M., Kim, J.H. and Cho, H.H. Infrared signature of UAV according to engine lobed mixer angle control, KSFM Winter Conference, 2018, Yeosu, Korea, November 2018.Google Scholar
Sircilli, F., Retief, S.J.P., Maglhaes, L.B., Ribeiro, L.R., Zanandrea, A., Brink, C., Nascimento, M. and Dreyer, M.M. Measurements of a Micro Gas Turbine Plume and Data Reduction for the Purpose of Infrared Signature Modeling, vol. 15. IEEE, 2015.Google Scholar
Shan, Y., Zhang, J.-Z. and Huang, G.-P. Experimental and numerical studies on lobed ejector exhaust system for micro turbojet engine, Eng Appl Computat Fluid Mech, 2011, 5, pp 141–148.Google Scholar
Barber, T., Paterson, R.W. and Skebe, S.A. Turbofan forced mixer lobe flow modeling - experimental and analytical assessment, NASA Contractor Report 4147.Google Scholar
Joo, M.L. A Study of the Infrared Signal for Aircraft Engine Exhaust Plume with Bypass Ratio, Chonbuk National University Graduate School, 2019.Google Scholar