Study of Decay Characteristics of Hexagonal and Square Supersonic Jet
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Prasanta Kumar Mohanta
und
B. T. N. Sridhar
Abstract
Experiments were carried on nozzles with different exit geometry to study their impact on supersonic core length. Circular, hexagonal, and square exit geometries were considered for the study. Numerical simulations and schlieren image study were performed. The supersonic core decay was found to be of different length for different exit geometries, though the throat to exit area ratio was kept constant. The impact of nozzle exit geometry is to enhance the mixing of primary flow with ambient air, without requiring tab, wire or secondary method to increase the mixing characteristics. The non-circular mixing is faster comparative to circular geometry, which leads to reduction in supersonic core length. The results depict that shorter the hydraulic diameter, the jet mixing is faster. To avoid the losses in divergent section, the cross section of throat was maintained at same geometry as the exit geometry. Investigation shows that the supersonic core region is dependent on the hydraulic diameter and the diagonal. In addition, it has been observed that number of shock cells remain the same irrespective of exit geometry shape for the given nozzle pressure ratio.
Nomenclature
- A
Area of the nozzle [m2]
- a
Semi-major axis [m]
- b
Semi-minor [m]
- CCD
Charged Coupled Device
- D
Exit diameter of circular nozzle [m]
- Dh
Hydraulic diameter of the nozzle [m]
- D
Diagonal of nozzle exit geometry [m]
- k
Turbulent Kinetic Energy (TKE) [m2s–2]
- Lc
The supersonic core length [m]
- M
Mach number
- P
Pressure [Nm–2]
- Pt
Pressure measured by Pitot tube [Nm–2]
- R
Outer radius of nozzle [m]
- T
Temperature [K]
- u
Velocity component in x direction [ms–1]
- x, y, z
Cartesian coordinate system
Dissipation Rate [m2s–3]
- Superscript and subscript
- *
Throat condition
- 0
Reservoir condition
- a
Atmospheric condition
- e
Exit condition
References
1. Bradbury LJS, Khadem AH. The distortion of a jet by tabs. J Fluid Mech 1975;70:801–13.10.1017/S0022112075002352Suche in Google Scholar
2. Ahuja KK, Brown WH. Shear flow control by mechanical tabs. AIAA Paper, 1989.10.2514/6.1989-994Suche in Google Scholar
3. Sreejith RB, Rathakrishnan E. Cross-wire as passive device for supersonic jet control. AIAA Paper, 2002.Suche in Google Scholar
4. Srinivasan K, Tide PS. Effect of chevron count and penetration on the acoustic characteristics of chevron nozzles. Appl Acoust 2009;71:201–220.10.1016/j.apacoust.2009.08.010Suche in Google Scholar
5. Manivannan P, Sridhar BTN. Characteristic study of non-circular incompressible free jet. Therm Sci 2013;17:787–800.10.2298/TSCI110208116MSuche in Google Scholar
6. George WK. Lectures in turbulence for the 21st century, Department of Aeronautics Imperial College of London, UK and Professor of Turbulence Emeritus Department of Applied Mechanics, Chalmers University of Technology Gothenburg, Sweden, 16 January 2013, pp. 65.Suche in Google Scholar
7. Mariani R, Kontis K. Effects of exit nozzle diameter on compressible vortex rings flow structure, 47th AIAA Aerospace Sciences Meeting Including The New Horizons Forum and Aerospace Exposition, 5–8 January 2009.10.2514/6.2009-410Suche in Google Scholar
8. Mi J, Nathan GJ, Luxton RE. Centerline mixing characteristics of jets from nine differently shaped nozzles. Exp Fluids 2000;28:93–4.10.1007/s003480050012Suche in Google Scholar
9. Quinn WR. Measurements in the near flow field of an isosceles triangular free jet. Exp Fluids 2005;39:111–26.10.1007/s00348-005-0988-2Suche in Google Scholar
10. Zaman KBMQ. Spreading characteristics of compressible jets from nozzles of various geometries. J Fluid Mech 1999;383:197–228.10.1017/S0022112099003833Suche in Google Scholar
11. Gutmark E, Schadow KC, Wilson KJ. Subsonic and supersonic combustion using noncircular injectors. J Propul Power 1991;27:240–9.10.2514/3.23317Suche in Google Scholar
12. Bayeh AC. Analysis of Mach disks from an under expanded nozzle using experimental and computational methods, 47th AIAA Aerospace Sciences Meeting Including The New Horizons Forum and Aerospace Exposition, 5–8 January 2009, pp. 2.10.2514/6.2009-217Suche in Google Scholar
13. http://www.meas-spec.com/product/tm_product.aspx?id=9290Suche in Google Scholar
14. Rathakrishnan E. Applied gas dynamics. New Jersey: Wiley Publication, 2010:pp. 497. Chapter 12 Jet. ISBN: 978–0–470–82576–1.Suche in Google Scholar
15. Raman G, Hailye M, Rice EJ. Flip-flop jet nozzle extended to supersonic flows. AIAA J June 1993;31.10.2514/3.11725Suche in Google Scholar
16. Paul Pao S, Abdol-Hamid KS. Numerical simulation of jet aerodynamics using the three-dimensional Navier-Stokes code PAB3D, NASA Technical Paper 3596, September 1996, 9–10.Suche in Google Scholar
17. Orescanin MM, Prisco D, Austin JM. Exhaust of underexpanded jets from finite reservoirs, AIAA 2010–5108, 40th Fluid Dynamics Conference and Exhibit, 2010, pp. 1010.2514/6.2010-5108Suche in Google Scholar
18. Sivaprakaash K, Jain S, Lovaraju P, Rathakrishnan E. Flow characteristics of passive controlled underexpanded co-flow jets. Int J Syst Technol 2008;1:55–65. ISSN 0974–2107.Suche in Google Scholar
19. Lovaraju P, Clement S, Rathakrishnan E. Effect of cross-wire and tabs on sonic jet structure. Shock Waves 2007. DOI 10.1007/s00193-007-0092–z.10.1007/s00193-007-0092-zSuche in Google Scholar
20. Srinivasarao T, Lovaraju P, Rathakrishnan E. Effect of co-flow on near field shock structure. J Fluids Eng July 2012;Vol. 134:074501–1. DOI: 10.1115/1.4006911.Suche in Google Scholar
© 2017 Walter de Gruyter GmbH, Berlin/Boston
Artikel in diesem Heft
- Frontmatter
- Study of Decay Characteristics of Hexagonal and Square Supersonic Jet
- Investigation on the Film Cooling Performance of Diffuser Shaped Holes with Different Inclination Angles
- Model-based Acceleration Control of Turbofan Engines with a Hammerstein-Wiener Representation
- Fatigue Life Prediction of Low Pressure Turbine Shaft of Turbojet Engine
- Influence of Geometry on Rotordynamic Coefficients of Brush Seal
- Numerical Investigation of Transient Flow in a Prototype Centrifugal Pump during Startup Period
- Thrust Performance Evaluation of a Turbofan Engine Based on Exergetic Approach and Thrust Management in Aircraft
- Real-time Simulation of Turboprop Engine Control System
- Ignition Study on a Rotary-valved Air-breathing Pulse Detonation Engine
Artikel in diesem Heft
- Frontmatter
- Study of Decay Characteristics of Hexagonal and Square Supersonic Jet
- Investigation on the Film Cooling Performance of Diffuser Shaped Holes with Different Inclination Angles
- Model-based Acceleration Control of Turbofan Engines with a Hammerstein-Wiener Representation
- Fatigue Life Prediction of Low Pressure Turbine Shaft of Turbojet Engine
- Influence of Geometry on Rotordynamic Coefficients of Brush Seal
- Numerical Investigation of Transient Flow in a Prototype Centrifugal Pump during Startup Period
- Thrust Performance Evaluation of a Turbofan Engine Based on Exergetic Approach and Thrust Management in Aircraft
- Real-time Simulation of Turboprop Engine Control System
- Ignition Study on a Rotary-valved Air-breathing Pulse Detonation Engine
