Effect of Electrode Distances on Combustion Behavior of Fuel Droplet in Vertical DC Electric Field(Thermal Engineering)

Flame is affected by external electric field because it contains ions and electrons related to chemical reaction. On the other hand, movement of ions and electrons affects external electric field due to their charge. Since there are a few studies to discuss the change of external electric field, this paper discusses the change of electric field from the experimental results with different electrode distance. It is supposed from 1-D steady-state analysis that if electric field is changed spatially the effect of electric field on combustion behavior is aligned with V^2/L^3 where V is applied voltage between electrodes and L is distance between the electrodes. Because flame deforms to cathode due to electric body force in electric field, the change of flame shape of burning ethanol droplet is observed in vertical DC electric field and electric current during combustion is measured. The result shows there exists the applied electric voltage where flame becomes vertically symmetry to balance the buoyancy by the electric body force and relation between m and n of V^m/L^n for flame symmetry is n/m=1.5. Depending on this result, it is proved that all experimental results with different electrode distance are aligned well with εV^2/L^3 which is a representing electric body force and the change of electric field due to the existence of flame can be estimated by brief 1D steady-state analysis.