Experimental Study on Combustion Characteristics of Iron Powder Burner Based on Product Analysis

The iron powder is considered as a potential green renewable metallic fuel. In order to explore the feasibility of using iron powder fuel, improve the design method of iron powder burner, study the combustion characteristics of iron powder and finally realize the effective use of energy after iron powder combustion, the self-sustained combustion of iron powder and air at atmospheric pressure was realized using the self-designed burner. The evolutionary law of the product and the combustion efficiency were researched as well. Results of the ignition and combustion experiments show that the optimum concentration of iron powder for ignition is 0.95~1.28kg/m3. The products were analyzed using scanning microscopy (SEM), laser particle size analyzer(LPSA), focused ion beam(FIB), X-ray diffraction(XRD)and other diagnostic methods. Results show that the morphology of iron particles would change from irregular to spherical after combustion. The products generated during the combustion process would be directly wrapped on the surface of the metal droplets, resulting in an increase of the product size. When the air-fuel ratio is 0.55, the increase rate of particle size is 1.2, which increases as the air-fuel ratio increases under fuel-rich condition. The multi-layer structure would form as the iron particle burns according to the analysis results of the phase diagram. The FIB method is used to further analyze the distribution of components from outside to inside, being Fe2O3, Fe3O4, FeO and Fe in the middle stage of combustion. © 2022, Editorial Department of Journal of Propulsion Technology. All right reserved.