Flame experiments

Hyperspectral images of flames have been acquired using the hyperspectral LWIR camera. The hope is to be able to distinguish between different kinds of fuel and identify different reaction regimes within the flames. The fuels are not premixed, meaning pure fuel is expelled from the nozzle where it then mixes with the air in order to maintain a sustaining flame (Fig. 1). Only simple and pure and fuels are used in the hope that the reactions (and hereby the spectral components) are simpler.

Fig 1: Experimental setup (not to scale)

Firstly, no additional filters are used besides the scanning Fabry-Pérot interferometer (SFPI). The relationship between the transmission of the SFPI, the wavelength (or wavenumber) of the incident light, and the mirror separation can be illustrated as in Fig. 2. Note here, that the response of the detector has not been taken into account.

Fig 2: Transmission profile of SFPI

No additional filters

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Long wave pass filter

Fig 9: Transmission profile of SFPI with long-wave pass filter

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Band pass filter

Fig 16: Transmission profile of SFPI with band pass filter

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Band pass and long pass filter

Fig 23: Transmission profile of SFPI with band pass and long wave pass filter

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