Abstract
An application of the electrospray to mesoscale combustion is studied, with the ultimate goal of coupling the combustor with direct energy conversion modules for power production. The combustor design relies on fuel dispersion by multiplexed electrosprays coupled with a series of catalytic meshes acting as ground electrode and initiators of the fuel oxidation. The combustor has a volume on the order of few cm3 and operates on jet fuel (JP8), which is electrosprayed at a flow rate on the order of 10 g/h with equivalence ratios varying from 0.35-0.70. The behavior of the electrospray in high temperature environments is examined and the phenomenology of the electrospray in the combustion chamber is visualized using planar laser-induced fluorescence from a fluorescent tag doped into the fuel. Combustion efficiencies on the order of 97% can be achieved with uniform temperatures at the catalyst in the range of 900-1,300 K (within ±5%) when the electrospray is operated in an unsteady mode, accompanied by a “hissing” sound characteristic of the onset of corona discharge. Remarkably, no fouling, soot, or NOx were detected in the exhaust gases, which resulted in clean and efficient combustion of even environmentally problematic liquid hydrocarbons.
