Numerical simulation of chemical ablation and mechanical erosion in hybrid rocket nozzle

Chemical ablation and mechanical erosion of hybrid rocket nozzles can cause loss of nozzle thermal protection material, resulting thrust reduction. In this paper, the chemical ablation and mechanical erosion mechanisms of nozzle thermal protection materials are studied through numerical simulation. For chemical ablation, a coupled thermal-mechanical-chemical model is established, considering three mechanisms: wall regression caused by non-homogeneous chemical reactions at the wall, convective heat transfer and fluid-structure interaction. For mechanical erosion, a Fluent DPM model and an Abaqus DEM model are established, which are investigated from the perspectives of empirical formula and solid mechanics mechanisms respectively, and validated against each other. The comprehensive effect of chemical ablation and mechanical erosion on the morphology of the nozzle is considered. The results show that both chemical ablation and mechanical erosion dominate the wall regression rate at the downstream of the converging section and upstream of the throat while the other location is only dominate by chemical ablation. After 5s of operation, thrust of rocket engine decreases by 5.8%. The Abaqus DEM model presented by this paper breaks the limitations of the empirical formulae due to the introduction of the material constitutive model and the failure criterion.

Automated summary

This paper investigates the chemical ablation and mechanical erosion mechanisms of nozzle thermal protection materials in hybrid rocket nozzles through numerical simulation. The study finds that both chemical ablation and mechanical erosion have significant effects on the wall regression rate of the nozzle at specific locations, and that the thrust of the rocket engine decreases over time.