Experiments in Fluids

, Volume 37, Issue 4, pp 566–576 | Cite as

Mixing efficiency measurements using a modified cold chemistry technique

  • T. Rossmann
  • M. G. Mungal
  • R. K. Hanson
Original Paper


The efficient mixing of fluids in compressible shear layers is still of fundamental importance to high-speed propulsion. To further understand the role of compressibility, measurements of mixing efficiency are performed in a convective Mach number=2.64 shear layer. The mean scalar field and estimated mixing efficiency are measured using a new “cold chemistry” technique utilizing the quenching of nitric oxide laser-induced fluorescence to mark regions of molecularly mixed fluid. Several different quenching partners are used to achieve statistically converged results using fewer images than previous techniques. The mixing efficiency (δm/δ) measured in this study at a Reynolds number of 1.9×106 is 0.64, following an increasing trend with both Reynolds number and compressibility when taken with previously measured cold chemistry results.


Shear Layer Mixture Fraction Shock Tunnel Mixed Fluid Entrainment Ratio 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. Batt RG (1977) Turbulent mixing of passive and chemically reacting species in a low-speed shear layer. J Fluid Mech 82:53–95Google Scholar
  2. Bond CL, Dimotakis PE (1996) Molecular mixing in high Reynolds number, subsonic, free shear layers. In: Fall meeting of the western states section of the combustion institute, Los Angeles, CA, paper no 96F-099Google Scholar
  3. Breidenthal RE (1981) Structure in turbulent mixing layers and wakes using a chemical reaction. J Fluid Mech 125:397–409Google Scholar
  4. Breidenthal RE (1992) Sonic eddy: A model for compressible turbulence. Am Inst Aeronaut Astronaut J 30:101–104Google Scholar
  5. Broadwell JE, Breidenthal RE (1982) A simple model of mixing and chemical reaction in a turbulent mixing layer. J Fluid Mech 125:397–409Google Scholar
  6. Clemens NT, Mungal MG (1995) Large-scale structure and entrainment in the supersonic mixing layer. J Fluid Mech 284:171–216Google Scholar
  7. Clemens NT, Paul PH (1995) Scalar measurements in compressible axisymmetric mixing layers. Phys Fluids 7:1071–1081CrossRefGoogle Scholar
  8. Dimotakis PE (1991) Turbulent mixing and combustion. In: Murthy SNB, Curran ET (eds) High-speed flight propulsion systems: Progress in aeronautics and astronautics. Am Inst Aeronaut Astronaut J 137:265–340Google Scholar
  9. Dowling DS, Dimotakis PE (1990) Similarity of the concentration field in gas-phase turbulent jets. J Fluid Mech 218:109–142Google Scholar
  10. Freund JB, Moin P, Lele SK (2000) Compressibility effects in a turbulent annular mixing layer, Part 2: Mixing of a passive scalar. J Fluid Mech 421:269–291CrossRefGoogle Scholar
  11. Frieler CE (1992) Mixing and reaction in the subsonic 2-d turbulent free shear layer. PhD Thesis, California Institute of TechnologyGoogle Scholar
  12. Frieler CE, Mungal MG (1988) The effects of Damköhler number in a turbulent shear layer. Combust Flame 71:23–34CrossRefGoogle Scholar
  13. Hall JL, Dimotakis PE, Rosemann H (1991) Some measurements of molecular mixing in compressible turbulent mixing layers. In: 22nd fluid dynamics, plasma dynamics and lasers conference, Am Inst Aeronaut Astronaut, paper no 91-1719Google Scholar
  14. Hanson RK, Seitzman JM, Paul PH (1990) Planar laser-fluorescence imaging of combustion gases. Appl Phys B 50:441–454Google Scholar
  15. Hu H, Koochesfahani MM (2002) A novel method for instantaneous, quantitative measurement of molecular mixing in gaseous flows. Exp Fluids 33:202–209Google Scholar
  16. Island TC (1997) Quantitative scalar measurements and mixing enhancement in compressible shear layers. PhD Thesis, Stanford University, CAGoogle Scholar
  17. Island TC, Patrie BJ, Mungal MG, Hanson RK (1996) Instantaneous three-dimensional flow visualization of a supersonic mixing layer. Exp Fluids 20:249–256Google Scholar
  18. Karasso PS, Mungal MG (1996) Scalar mixing and reaction in plane liquid shear layers. J Fluid Mech 323:23–63Google Scholar
  19. Konrad JH (1977) An experimental investigation of mixing in two-dimensional turbulent shear flows with application to diffusion-limited chemical reactions. PhD Thesis, California Institute of TechnologyGoogle Scholar
  20. Koochesfahani MM, Dimotakis PE (1986) Mixing and chemical reactions in a turbulent liquid mixing layer. J Fluid Mech 170:83–112Google Scholar
  21. Lee MP, McMillin BK, Hanson RK (1993) Temperature measurements in gases by use of planar laser-induced fluorescence imaging of NO. Appl Opt 32:5379–5396Google Scholar
  22. McDermid IS, Laudenslager JB (1982) Radiative lifetimes and electronic quenching rate constants for single-photon excited rotational levels of NO (A2Σ+, n’=0). J Quant Spect Radiat Transfer 27:483–492CrossRefGoogle Scholar
  23. McMillin BK, Palmer JL, Hanson RK (1993) Temporally resolved, two-line fluorescence imaging of NO temperature in a transverse jet in a supersonic cross flow. Appl Opt 32:7532–7545Google Scholar
  24. Meyer TR, King GF, Martin GC, Lucht RP, Schauer FR, Dutton JC (2002) Accuracy and resolution issues in NO/Acetone PLIF measurements of gas-phase molecular mixing. Exp Fluids 32:603–611CrossRefGoogle Scholar
  25. Mungal MG, Dimotakis PE (1984) Mixing and combustion with low heat release in a turbulent shear layer. J Fluid Mech 148:349–382Google Scholar
  26. Mungal MG, Frieler CE (1988) The effect of Damköhler number in a turbulent shear layer. Combust Flame 71:23–34CrossRefGoogle Scholar
  27. Papamoschou D, Roshko A (1988) The compressible turbulent shear layer: An experimental study. J Fluid Mech 197:453–477Google Scholar
  28. Paul PH, Gray JA, Durant JL Jr, Thoman JW Jr (1996) Collisional electronic quenching rates for NO (A2Σ+, n’=0). Chem Phys Let 259:508–514CrossRefGoogle Scholar
  29. Paul PH, Clemens NT (1993) Sub-resolution flowfield measurements of unmixedness using electronic quenching of NO A2Σ+. Opt Let 18:161–164Google Scholar
  30. Rossmann T, Mungal MG, Hanson RK (1999) A new shock tunnel driven facility for high compressibility mixing layer studies. In: 37th aerospace sciences meeting, Am Inst Aeronaut Astronaut, Reno, NV, 11–14 Jan, paper no 99–0415Google Scholar
  31. Rossmann T, Mungal MG, Hanson RK (2002) Evolution and growth of large-scale structures in high compressibility mixing layers. J Turb 3:1–19CrossRefGoogle Scholar
  32. Rossmann T, Mungal MG, Hanson RK (2003) NO PLIF applied to low-pressure hypersonic flow fields for imaging of mixture-fraction. Appl Opt 42:6682–6695PubMedGoogle Scholar
  33. Yip B, Lozano A, Hanson RK (1994) Sensitized phosphorescence: A gas phase molecular mixing diagnostic. Exp Fluids 17:16–23Google Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Mechanical Engineering DepartmentStanford UniversityUSA
  2. 2.Mechanical and Aerospace Engineering DepartmentRutgers UniversityPiscatawayUSA

Personalised recommendations