Modification of sooting tendency by magnetic effects

Experimental investigations assess for the first time the influence of the gradient of the square of the magnetic flux density (∇(B²)) on the soot production in a laminar axisymmetric non-premixed flame. The steady non-smoking ethylene flame is established in a coflowing mixture, composed of oxygen and nitrogen, over a Santoro type burner. This burner is located in an electromagnet. The flame experiences different magnitudes of upward ∇( B²), ranging from 0 to 18.2 T²/m, as well as different oxygen contents of the coflow, ranging from 21% to 50% in volume. Soot volume fraction is mapped in the flame by Laser Extinction Measurement technique. Increasing the magnitude of the ∇(B²) allows for the modification of soot production in the flame. This modification is enhanced by increasing oxygen content, as oxygen exhibits a relatively high paramagnetic susceptibility. Furthermore, the aforementioned modification is shown to enable the shift among similar soot concentration profiles in the flame, just as the variation of oxygen content can do. Consequently, modification of the inner flame structure by magnetic effects could contribute to the control of oxyfuel combustion.