Mathematical Model of Critical Condition for Friction Ignition

The effect of friction on the critical temperature of ignition is considered by establishing the friction ignition model based on the principle of the heterogeneous reaction of Semenov. The effects of the oxygen concentration, flow velocity, friction force, and contact area on the critical temperatures of two fireproof titanium alloys (TB12 and TF550) are studied. The results show that the critical temperature decreases with an increase in the oxygen concentration and increases with the flow velocity. The critical temperature increases approximately linearly with an increase in the friction force and decreases exponentially with an increase in the contact radius. As the contact radius increases to 0.007 m, the critical temperatures of TF550 and TB12 are 1029 and 1016 K, respectively. As the contact radius reaches 0.014 m, the critical temperatures of TF550 and TB12 are 962 and 960 K, respectively.