Preliminary Study on ECT Imaging of Flames in Porous Media

S. Liu1, Q. Chen2, X. Xiong3, Z. Zhang3, and X.K. Liu4

1School of Energy and Power Engineering, North China Electrical Power University, Beijing, China, Email: s.liu@mail.etp.ac.cn

2School of Mechanic and Electronic Control Beijing Jiaotong University

3National Natural Science Foundation of China, 83 Shuangqing Road, Haidian Dist. Beijing, China

4Beijing association of science and technology, Beijing, China

ABSTRACT

Combustion in porous media is becoming a important technique in the utilization of gaseous fuels due to its high efficiency, low pollution, and broad power dynamic ranges. The fluctuation and uniformity of the flame distribution inside the porous media are essential aspects for the desired combustion conditions. However, the flame distribution inside a porous medium cannot easily be monitored since it is not possible to ‘see’ through the medium by conventional visualization techniques. In this study, the cross-sectional profiles of flames inside a porous medium are imaged by electrical capacitance tomography (ECT). First, the relationship between the flame ionization and the relative permittivity is established as the basis for ECT imaging of flames; second, image reconstruction algorithms are discussed and an online iterative method OIOR is selected; finally, experimental measurements are carried out and images of flames are reconstructed. The shape, size and motion of the flames are clearly monitored in the measuring zone.

Keywords ECT, porous media, combustion visualization