Comparative experimental and numerical investigation of a piloted turbulent natural-gas diffusion flame
- Delft Univ. of Technology (Netherlands)
A turbulent natural-gas diffusion flame is investigated both experimentally and numerically. Measured quantities involve mean velocity, turbulence characteristics, mean temperatures, visualization of the OH reaction zone and passive scalar concentration, and statistical analysis of OH concentrations. The configuration is a laboratory-scale piloted diffusion flame with annular coflowing air, placed in a ventilated confinement, of well-defined initial and boundary conditions. The fuel jet velocity is 23.2 m/s, and the annular air velocity is 5.1 m/s. The techniques used are laser-Doppler anemometry (LDA), thermocouple measurements, and 1D- and 2D-laser induced fluorescence (LIF). The mathematical model is based on a constrained-equilibrium conserved-scalar model, resembling a laminar flamelet model, with a standard {kappa}-{epsilon} turbulence model and a four-flux radiation model. Comparisons up to 42 jet diameters downstream of the burner nozzle show good agreement for mean axial velocity and temperature. The turbulence quantities are qualitatively reproduced by the {kappa}-{epsilon} turbulence model. The OH radical concentrations are underpredicted because of the lack of superequilibrium effects in the chemistry model. In addition, the profile shapes do not correspond very well. The data support the applicability of a conserved-scalar model with an assumed {beta}-function probability density function (PDF) shape for mean temperature predictions. For OH predictions, however, the conserved-scalar approach does not hold.
- OSTI ID:
- 93275
- Report Number(s):
- CONF-940711--
- Country of Publication:
- United States
- Language:
- English
Similar Records
A test of a flamelet model for turbulent nonpremixed combustion
Superequilibrium and thermal nitric oxide formation in turbulent diffusion flames