Wide-field conserved scalar imaging in turbulent diffusion flames by a Raman and Rayleigh method
- Univ. of Sydney (Australia). Dept. of Mechanical and Mechatronic Engineering
A new experimental approach to two-dimensional (2D) measurements of mixture fraction and other scalars in turbulent flames has been developed, based on simultaneous fuel Raman and Rayleigh imaging. The inherently weak Raman signal is enhanced by high laser energy, low f-number optics, and a multipass cell. Measurements have been obtained in piloted flames of air-diluted methane, at Reynolds number 28,000--53,000. With the assumptions of unity Lewis number and a one-step reaction, single-shot images of mixture fraction, fuel mass fraction, and temperature have been derived with spatial resolution of about 10 Kolmogorov scales. Advantages and difficulties in the use of the multipass cell are discussed and some early results presented. The wide-field images enable determination of scalar turbulence macroscales that are found to be anisotropic and to vary with radius. The location of the instantaneous stoichiometric mixture fraction contours indicates that there is little reaction in the outer regions where entrainment takes place. Generally, the stoichiometric contour is aligned with regions of high scalar dissipation.
- OSTI ID:
- 93264
- Report Number(s):
- CONF-940711-; TRN: IM9537%%308
- Resource Relation:
- Conference: 25. international symposium on combustion, Irvine, CA (United States), 31 Jul - 5 Aug 1994; Other Information: PBD: 1994; Related Information: Is Part Of Twenty-fifth symposium (international) on combustion; PB: 1838 p.
- Country of Publication:
- United States
- Language:
- English
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