Ignition Resistance of Polymeric Materials to Particle Impact in High-Pressure Oxygen

Particle impact ignition has been the primary cause of numerous fires in oxygen systems. This ignition phenomenon is known to occur where particles are present in high-velocity gas and where impact occurs on a flammable material. The particle impact ignition behavior of many metals has been widely studied, but the particle impact ignition behavior of polymeric materials is relatively unknown. Particle impact ignition in polymeric materials is a concern because these materials are commonly used in component seat and seal applications where high-velocity particle impacts can occur. This study evaluates several polymeric materials and compares the threshold temperature, which is the minimum temperature required for ignition, of these materials: Kel-F 81® (CTFE), Teflon® (TFE), polyetheretherketone (PEEK), and Vespel SP-1®(polyimide). The materials were configured as targets in the high-velocity particle impact test system at the NASA White Sands Test Facility. Gaseous oxygen was flowed at 27.5 MPa (4000 psig) and sonic velocity, and the targets were impacted with 2000-μm (0.078-in.) aluminum 2017 particles. This paper discusses the results of these tests and ranks the materials according to their threshold temperatures at these conditions.