Experimental studies on the burning of coated and uncoated micro and nano-sized aluminium particles

P. Escot Bocanegra (1) , C. Chauveau (1) , I. Gökalp (1)

1 LCSR - Laboratoire de combustion et systèmes reactifs

In this work, two different techniques are used to reduce the burning times of aluminum particles with the ultimate goal to improve performance of solid propellants. One method is to coat the particles by nickel, and the second is to decrease the particle size to nanometric scale. A thin coating of Ni on the surface of Al particles can prevent their agglomeration and at the same time facilitate their ignition, thus increasing the efficiency of aluminized propellants. In this work, ignition of single Nicoated Al particles is investigated using an electrodynamic levitation setup and laser heating of the particles. The levitation experiments are used to measure the particle ignition delay times and burning times at different Ni contents in the particles. Decreasing the size of Al particles increases their specific surface, and hence decreases the burning time of the same mass of particles. In this investigation, a cloud of Al nanoparticles suspended in a tube is ignited by an electric spark. The cloud experiments are used to measure the flame front propagation velocity for different particle sizes and different coatings. The results and their analysis show that both methods reduce the Al burning time. Ni coating reduces significantly the ignition time of micro sized Al particles and hence the total burning time compared to non-coated particles. The nano-sized particle clouds also burn faster than micro-sized Al particle clouds.

Mots clés: Particles; Nano -particles; Combustion; Aluminum

Domaines: Milieux fluides et réactifs

P. Escot Bocanegra, C. Chauveau, I. Gökalp. Experimental studies on the burning of coated and uncoated micro and nano-sized aluminium particles. European Conference for Aerospace Sciences (EUCASS), Jul 2005, Moscow, Russia. pp.33-38, ⟨10.1016/j.ast.2006.10.005⟩. ⟨hal-02018395⟩