Measurement of temperature and temperature profile of wick stabilized micro diffusion flame under the effect of magnetic field using digital speckle pattern interferometry

摘要

The effect of upward decreasing, uniform, and upward increasing magnetic fields on the temperature and temperature profile of a wick stabilized micro diffusion flame is investigated experimentally by using digital speckle pattern interferometry (DSPI). DSPI fringe patterns have inherent speckle noise which leads to inaccuracies in the measurements. To extract data more accurately, the high frequency speckle noise in a DSPI fringe pattern is reduced by using the combination of median filter and Symlet wavelet filter. The optical phase is extracted from the filtered DSPI fringe pattern by using Hilbert transform. The obtained phase is used to calculate the refractive index and temperature distribution in a microflame created by a candle. Temperature in the micro diffusion flame was determined experimentally both in the absence and in the presence of upward decreasing, uniform, and upward increasing magnetic fields. The experimental results reveal that temperature is increased under the effect of uniform and upward decreasing magnetic fields in comparison to the temperature of the micro-flame without a magnetic field. This is in contrast to the normal diffusion flame, where under a uniform magnetic field, there was no effect on temperature. In the case of an upward increasing magnetic field, the temperature of the microflame decreased.