固体火箭发动机药柱包覆套外侧狭缝传热特性OA

The slit on the outer side of grain cladding jacket in solid rocket motor may widen under high overload conditions,posing a risk of flame-proof failure and premature ignition of propellant.To investigate the heat transfer characteristics of the slit to the propellant grain,a numerical simulation study was conducted using dynamic mesh method.Results indicate that when the slit width is small at the initial moment,the heat transfer by convection is stronger than that by conduction at the initial period,leading to a rise in the grain surface temperature.After the flow inside the slit stabilizes,the heat transfer by convection becomes lower than that by the conduction,causing the grain surface temperature to decrease.When the width of the slit is large,vortices form at the slit inlet,enhancing the heat transfer from the external gas to the gas inside the slit.Consequently,the grain surface temperature increases continuously during the combustion.The burning surface regression rate does not significantly affect the internal flow within the slit and has little influence on the heat transfer process.In conclusion,for narrow slits on the outer side,special attention should be paid to the temperature variation at the initial stage of combustion.If the flight mission involves high overload conditions,the possibility of slit widening and enhanced heat transfer must be considered,and the thermal protection measures should be enhanced.