Analysis on faults in the nozzle throat insert of a pulse motor

In solving problems of breakage in nozzle throat inserts for a pulse motor, analysis on the strength of nozzle throat insert have been carried out using the MSC Patran 2004r2 finite element software. Triangular elements for axial symmetry structure were selected. Programs of variational pressure load were written with the PCL language. Compression resistance experiments to the whole nozzle were finished in a sealed container with high pressure. Relations of load, displacement restriction and material performance versus the maximum stress of the nozzle throat insert are here analyzed. The result of analysis showed that the anti-ablation property of the supporter for throat insert is not sufficient. The supporter for throat insert was then changed into one made of composite having a metal bush of higher anti-ablative property. Tests proved that the improved nozzles are effective and that their structures are successful.