Influence of reflected particles on the ablation of a body in a two-phase flow

Abstract

The article examines the results of an experimental investigation into the influence of reflected particles on oncoming particles when a two-phase stream flowed round a body. The two-phase flow had a continuous phase of air and a discrete phase of accurately fractionated electrocorundum particles 23 and 109 μm in diameter with a concentration of up to 0.25 kg of particles/kg of air. The velocity of the air was u = 200 m/sec and the velocity of the particles was u_s = 155–190 m/sec. The intensity of the interaction between the incident and reflected particles was determined by using the integral ablation characteristics of the models. Aluminum circular forward-pointing and inverted cones were used as models. A cloud of low-velocity reflected particles formed inside the inverted cones and prevented the oncoming particles from hitting the surface of the model. The half-angles of the cones were varied in the range α = 15–90 °. Dependences were obtained relating the probability of collision of the particles to the angle of incidence with the surface, their diameter, and the characteristic dimensions of the body in the flow, and also to their concentration. The results could, in principle, be used to develop new ablation-resistant materials with better antiablation properties than those used at present.