The effect of suspended carbon-black particles on the burning behavior of n-heptane pool fire

This study experimentally shows the influence of the suspended carbon black particles on the burning behavior of an n-heptane pool fire. The nanoscale black carbon was dispersed in n-heptane with ultrasonic oscillation method. Experiments with different initial fuel thicknesses (4 mm, 8 mm and 12 mm) and volume fractions (0.1%, 0.5%, and 1%) of carbon-black particles were conducted in a square steel-tray with dimensions of 0.18 m. The burning rate and fuel temperature were investigated. The results indicate that the maximum burning rate reduced with the increase of volume fraction. Nevertheless, for the case with a larger volume fraction of particles, a higher increasing rate of the burning rate was observed after ignition and experience a longer quasi-steady burning period. With the increase of initial fuel thickness, the burning rate increased and the effects of suspended carbon black enhanced. The boiling layer decreased significantly in the cases with high volume fraction along with a higher temperature gradient in the non-boiling layer. The radiation transmittance was the main cause of the larger burning rate increasing rate and thinner boiling layer in the nanofluids with higher carbon-black volume fraction.