Analysis of local ablation characteristics in combustion chamber of dual-pulse motor

Aimed at the local ablation enhancement problem in the 1st pulse combustion chamber of a dual-pulse motor, numerical simulation of the two-phase inner flow in two dual-pulse motors with φ203 mm and φ120 mm in caliber respectively was conducted. The vortex movement of gas in the combustion chamber and its two-phase characteristics were analyzed, which were induced by the chamber area sudden expansion. The heat convection intension on the chamber wall was computed by an expirical formula. By comparing the calculation results with the experinental data, it was revealed that the convection enhancement zone was consistent with the local ablation spot well. The chamber wall heat convection in the gas vortex region, especially near the reattachment point, was much higher than in the other chamber wall regions, which caused the local ablation enhancement. In addition, when the propulsion grain had metal involved, a portion of metal-oxide particles in smaller size were carried into the vortex zone and moved to the upstream chamber wall. Those particles may deposit on the chamber wall.