Solid rocket motor nozzle provide thrust for aircraft through effectively translating gas energy into kinetic energy to the by controlling the gas expansion chamber,tungsten copper nozzle throat insert throat has the function of limiting throat insert expand for ablation , which directly decrease the thrust .When solid rocket motor sparking, the temperature of nozzle throat insert increases to 2000,producing great temperature gradient and thermal stress which easily makes throat insert crack. If the throat ablate serious in working, it is difficult to maintain a stable pneumatic shape even fragmented which will directly influence thrust and efficiency or even lose productive capacity.
The working mechanism of tungsten copper military nozzle throat insert made of graphite is that the graphite absorb heat by sublimating under high temperature and then dissipate heat with far fewer units of material consumption but scattering large mount of heat so that the nozzle of solid rocket motor will cool down. But graphite do not sublimate at the temperature lower than 3,400 Celsius degree, however, throat inserts’ working temperature of general engine is 3000 Celsius degree or so, so the sublimation of carbon is not the good exothermic mechanism for throat insert.
While the tungsten copper military nozzle throat insert
made of tungsten coppe ralloy, the copper melts when the surface
temperature at a high level and forming liquidfilm attached to the
nozzle throat insert surface, producing the thermal resistance effects
and prevent heat from transferring into internal of material. So
tungsten copper alloy is more ideal materials for throat insert
compared with others.
没有评论:
发表评论