Enhancement of Jet Mixing using Stepped Tandem Tabs

Document Type : Regular Article

Authors

1 Department of Aeronautical Engineering, KCG College of Technology, Chennai, Tamil Nadu, 600 097, India

2 Department of Aerospace Engineering, MIT Campus, Anna University, Chennai, Tamil Nadu, 600 044, India

3 Department of Aerospace Engineering, Indian Institute of Technology, Kharagpur, West Bengal, 721 302, India

10.47176/jafm.17.05.2217

Abstract

Mixing characteristics of jet emerging from a subsonic nozzle exit has been experimented and the results are compared with uncontrolled jet and controlled jet configurations. The mixing enhancement was achieved using a passive method of jet control in which tandem tabs arrangement with rectangular cross section are fixed at the nozzle exit. Two Tab configurations, the Tandem tab (TT) and Stepped Tandem Tab (STT) are used to enhance the mixing characteristics of the jet, the aspect ratio (length /width) of the tabs was 1.67 offering a blockage ratio of 9.55% to the nozzle exit. The blockage ratio of TT and STT configurations are maintained to be equal so that the mixing characteristics can be compared. The axial and radial jet spread are compared for nozzle exit Mach numbers of 0.6, 0.8 and 1.0. The TT controlled jet offered a potential core reduction of 63%, 78% and 82% for Mach numbers 0.6, 0.8 and 1.0 respectively. The STT controlled jet offered a potential core reduction of 89%, 90% and 85% for Mach numbers 0.6, 0.8 and 1.0 respectively. The radial spread of uncontrolled jet, controlled jet with TT and STT are plotted at several X/D locations and found that the controlled jets have more jet spread in both radial directions. A simulation is conducted for jets with exit Mach number 0.8 and the results are validated with the experimental findings. Based on the preliminary experimentation and computation, the STT controlled jet achieved better jet mixing through more potential core reduction and radial spread characteristics as compared to the TT configuration and base nozzle. 

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Ahuja, K. K., & Brown W. H. (1989). Shear flow control by mechanical tabs. AIAA, 89, 0994. https://doi.org/10.2514/6.1989-994
Alam, M. M., Bai, H., & Zhou, Y. (2016). The wake of two staggered square cylinders. Journal of Fluid Mechanics, 801, 475–507. https://doi.org/10.1017/jfm.2016.303
Ahmed R. A., Thanigaiarasu, S., Santhosh, J., Elangovan, S., & Rathakrishnan, E. (2013). Study of slanted perforated jets, International Journal of Turbo & Jet Engines, 30(4), 347 – 357. https://doi.org/10.1515/tjj-2013-0015
Ahmed R. A., Thanigaiarasu, S., Venkatramanan, S., Elangovan, S., & Rathakrishnan, E. (2015). Study of slanted perforated shapes in tabs for control of subsonic Jets. AIAA, 2015-2423. https://doi.org/10.2514/6.2015-2423
Auteri, F., Belan, M., Gibertini, G., & Grassi, D. (2008). Normal flat plates in tandem: An experimental investigation. Journal of Wind Engineering and Industrial Aerodynamics, 96, 872–879. https://doi.org/10.1016/j.jweia.2007.06.014
Bohl, D. G., & Foss, J. F. (1996). Enhancement of passive mixing tabs by the addition of secondary tabs. AIAA, 96, 0545. https://doi.org/10.2514/6.1996-545
Bradbury, L. J. S., & Khadem, A. H. (1975). The distortion of a jet by tabs. Journal of Fluid Mechanics, 70(4), 801-813. https://doi.org/10.1017/S0022112075002352
Chand, D. S., Thanigaiarasu, S., Elangovan, S., & Rathakrishnan, E. (2011). Perforated arc-tabs for jet control. Int. J. Turbo Jet-Engines, 28, 133-138. https://doi.org/10.1515/tjj.2011.012
Gretta, W. J., & Smith, C. R. (1993). The flow structure and statistics of a passive mixing tab. Journal of Fluids Engineering, 115/255. https://doi.org/10.1115/1.2910133
Jabez Richards, S. B., Thanigaiarasu, S., & Kaushik, M. (2023). Experimental study on the effect of tabs with asymmetric projections on the mixing characteristics of subsonic jets. Journal of Applied Fluid Mechanics, 16(6), 1208-1217. https://doi.org/10.47176/jafm.16.06.1584
Lovaraju, P., Paparao, K. P. V., & Rathakrishnan, E. (2004). Shifted cross-wire for supersonic jet control. AIAA, 2004-4080. https://doi.org/10.2514/6.2004-4080
Maruthupandiyan, K., & Rathakrishnan, E. (2016). Supersonic jet control with shifted tabs. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 2018, 232(3):433-447. https://doi.org/10.1177/0954410016679197
Singh, N. K., and Rathakrishnan E. (2002). Sonic jet control with tabs. Journal of Turbo and Jet Engines, 19, 107-118. https://doi.org/10.1515/TJJ.2002.19.1-2.107
Rathakrishnan, E. (2012). Visualization of the flow fieldaround a flat plate. IEEE Instrumentation and Measurement Magazine, 15(6), 8-12. https://doi.org/10.1109/mim.2012.6365535
Rathakrishnan, E. (2019). Applied gas dynamics. John Wiley & Sons. https://doi.org/10.1002/9781119500377.ch12
Reddy, D. R., & Zaman, K. B. M. Q. (2006). Computational study of effect of tabs on a jet in a cross flow. Computers and Fluids, 35(7), 712–723. https://doi.org/10.1016/j.compfluid.2006.01.011
Samimy, M., Zaman, K. B. M. Q., & Reeder, M. F. (1993). Effect of tabs on the flow and noise field of an axisymmetric jet. AIAA, 31(4), 609–619. https://doi.org/10.2514/3.11594
Thanigaiarasu, S., Balamani, G., Mirnal, K., & Revathy, K. (2023). Computational study on the effect of vane design in enhancing the mixing of subsonic jet and sonic jet. Journal of Applied Fluid Mechanics, 16(12), 2316-2328. https://doi.org/10.47176/jafm.16.12.2092
Thanigaiarasu, S., Jabez Richards, S. B., Karthikeyan, V., Muthuram, A., Yadav, S. K., Vijaya Raj, T. (2020). Numerical Study on the Effect of Innovative Vortex Generators in the Mixing Enhancement of Subsonic Jets. Proceedings of International Conference of Aerospace and Mechanical Engineering 2019. Lecture Notes in Mechanical Engineering. Springer, Singapore. https://doi.org/10.1007/978-981-15-4756-0_35
Thanigaiarasu, S., Jayaprakash, S., Elangovan, S., & Rathakrishnan, E. (2008). Influence of tab geometry and its orientation on under-expanded sonic jets. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 222(3), 331-339. https://doi.org/10.1243/09544100JAERO299
Wilcox, D. C. (1993). Turbulence modeling for CFD. DCW Industries, Inc.
Zaman, K. B. M. Q. (1993). Streamwise vorticity Generation and mixing enhancement in free jets by delta-tabs. AIAA, 93, 3253. https://doi.org/10.2514/6.1993-3253
Zaman, K. B. M. Q., Reeder, M. F., & Samimy, M. (1992). Supersonic jet mixing enhancement by delta-tabs. AIAA, 92, 3548, 1992. https://doi.org/10.2514/6.1992-3548
Zaman, K. B. M. Q., Reeder, M. F., & Samimy, M. (1994). Control of an axisymmetric jet using vortex generators. Physics of Fluids, 6, 778-793. https://doi.org/10.1063/1.868316