Journal of Aeronautical Engineering

Journal of Aeronautical Engineering

Numerical Simulation and Survey of Heat Transfer of Flow Mixing in a Lobed Mixer of a Turbofan Engine

Document Type : Original Article

Authors
Sadegh Fazeli 1
Roohollah Khoshkhoo 2
Saeedreza Zadsirjan 3
1 Faculty of Mechanical Engineering, MUT
2 MUT
3 Maintenance Engineering Department, Mapna Turbine Engineering and Manufacturing Company (TOGA)
10.22034/joae.2021.139665
Abstract
Mixer, a component of turbofan engines is used to mix bypass cold flow with central body hot flow. In this study, the flow passing through the lobed mixer of a high bypass turbofan engine are simulated. First phase of the study was validation of the simulation method. The next phase was assessing the effect of heat transfer and mixing of hot and cold flows in the high bypass turbofan engine mixer. The results show that by raising the mixing length, the admixture of cold and hot flow increases regularly (layered) and the total temperature diminish. Alloy in mixer lobes plays the greatest role in this cooling process. Mixer successfully lowers 800 Kelvin temperature to of 340 Kelvin. The axial velocity of hot flow before entering the lobes is 210 m/s, decrease while passing the mixer lobes, re-boost in a short distance between the nozzle and the central body, eventually decreasing during flow exit. Besides, the transverse velocity generated deep inside the lobes have a substantial role in flow mixing.
Keywords
Mixer
Numerical Simulation
Mixing of Flow
Turbofan Engine
 [1].Skebe, S., Paterson, R., and Barber. T., “Experimental investigation of three-dimensional forced mixer lobe flow fields”, 1st National Fluid Dynamics Conference, 1988.
[2].Barber, T., “Turbofan forced mixer lobe flow modeling. 2: Three-dimensional inviscid mixer analysis (FLOMIX)”, NASA, ISBN: 1730957811, 1988.
[3].Shan, Y., Zhang, J., and Huang, G., “Experimental and numerical studies on lobed ejector exhaust system for micro turbojet engine”, Engineering Applications of Computational Fluid Mechanics, Vol. 5, No. 1, pp. 141-148, 2014.
[4].Xie, Y. and Y.h. Liu, “Numerical investigation of mixing length on performance of lobed forced mixer nozzles”, Heat Transfer—Asian Research, Vol, 40, No. 3, pp. 205-216, 2011.
[5].Brinkerhoff, J.R., H. Oria, and M.I. Yaras, Experimental and computational study of mixing mechanisms in an axisymmetric lobed mixer”, Journal of propulsion and power, Vol. 29, No. 5, pp. 1017-103, 2013.
[6].Saegeler, S.F. and C. Mundt. Advanced numerical simulation of mixing hot core and cold bypass flow in modern propulsion systems with internal lobed forced mixer. in 21st AIAA Computational Fluid Dynamics Conference. 2013.
[7].Gu, R., Xu, J., Fan, Z., Wang, Y., Guo, S., “Numerical Investigation of Performance of the Air Tab in the Turbofan Nozzle”, Journal of propulsion and power, Vol. 30, No.5, pp. 1272-1280, 2014.
[8].Sheng, Z., Huang, P., and Zhao, T., “Configurations of lobed nozzles for high mixing effectiveness”, International Journal of Heat and Mass Transfer, Vol. 91, pp. 671-683, 2015.
[9].Sheng, Z., “Jet mixing of lobed nozzles with spoilers located at lobe peaks”, Applied Thermal Engineering, Vol.119: pp. 165-175, 2017.
[10].Lei, H., Fan, W., Zhang, R., Wu, J., Zhang, Y., Xu, H., “Effect of inlet pre-whirl on two-dimensional lobed mixer performance”, IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 113, 2018.
[11].Sheng, Z., Liu, J., Yao, Y., Xu, Y., “Mechanisms of lobed jet mixing: About circularly alternating-lobe mixers”, Aerospace Science and Technology, Vol. 98, No. 105660, 2020.
[12].Fang, X., Shen, C., Sun, M., Sandberg, R., Wang, P., “Flow structures of a lobed mixer and effects of streamwise vortices on mixing enhancement”, Physics of Fluids, Vol. 31, No. 6, pp. 066102, 2019.
[13].İper, B., Ergin, C., Cenik, B., Suer, T., Uslu, S., “Investigation of the Effects of Lobe Number and Configuration on Mixing Performance in Lobed Mixer”, AIAA Propulsion and Energy Forum, AIAA No. 2020-3778, 2020.
[14].Krasnodebski, J. K., “Numerical simulations of lobed mixer flow fields”, Massachusetts Institute of Technology,Ms.c Thesis, 1995.
[15].Wang, S., Li, L., and Zhang, J., “Grid generation and numerical analysis of multi-stream flow in the complex channel with a forced mixer lobe”, Journal of Thermal Science, Vol. 13, No. 2,  pp. 167, 2014.
[16].Recktenwald, G., “The k-e Turbulence Model”, ME, Vol. 448, p. 548, ID. 53006658, 2009.
[17].Barber, T., R. Paterson, and S. Skebe, “Turbofan forced mixer lobe flow modeling. 1: Experimental and analytical assessment”, NASA Contractor Report 4147, 1988.
Journal of Aeronautical Engineering
Volume 23, Issue 1
June 2021
Pages 160-174

  • Receive Date 08 September 2021
  • Revise Date 27 October 2021
  • Accept Date 03 November 2021