Spectral radiation characteristics in semi-coke jet flame for energy utilization

Abstract

To provide a reference for research and design of the photo-thermal energy cascaded utilization system of fuel combustion, this paper studies the spectral radiation characteristics of the semi-coke jet flame from the perspective of radiative energy utilization. Based on a self-built Hencken flat-flame burner, the spectral radiation characteristics of the semi-coke flame are measured under O2/N2 and O2/CO2 atmospheres using an optical fiber spectrometer. In particular, the spectral radiative exergy characteristics are analyzed based on the second law of thermodynamics. It is found that the intensity of radiative energy and exergy increase, as does the proportion of spectral radiation below the wavelength of 3 μm, with the oxygen ratio and temperature under the experimental conditions. There is little difference between O2/CO2 and O2/N2 atmospheres in the effect on the spectral radiation characteristics. The spectral proportion in the waveband below 1.1 μm is about 7%, while that is over 60% in the waveband of 1.1–3 μm, showing considerable utilization potential. The proportion characteristics of spectral radiation exergy are similar to that of spectral radiation energy in the total spectrum. The spectral radiation in the waveband below 3 μm has higher energy quality because its exergy-to-energy ratio could reach between 76% and 85%. The main factor affecting the radiation exergy is temperature, whereas the influence of the waveband is not obvious. One-dimensional calculation cases of radiation transfer constructed according to the combustion characteristics can well simulate the proportion of spectral radiation. Further studies could adopt numerical simulation as a reasonable supplementary.