Ignition and Combustion Behavior in Solid Propellant Microsystems Using Joule-Effect Igniters

A study of solid propellant ignition and combustion of potassium dinitrobenzofuroxanate in Joule-heating pyrotechnical microelectromechanical systems igniters is carried out using a high-speed framing camera. The effect of igniter geometry, propellant formulation (binder content), fuel mass, and input power level on ignition delay time variability is investigated. Analytical heat transfer models of the ignition process were constructed based on the geometry of the igniters and successfully fitted to experimental ignition delay times. Complete combustion of the propellant drops was observed for fuel masses greater than 100 mu g. Flame speeds on the order of tens of centimeters per second were obtained. Two different ignition regimes were observed: a thermal ignition and a "direct ignition" regime.