Abstract: The response processes of hydroxyl terminated polyether (HTPE) propellant engines with different sizes and length-to-diameter ratios were simulated to analyze the effect of structure size on their slow cook-off response characteristics. The temperature distribution, reaction temperature, reaction time and reaction location of propellant were studied. A calculation method based on image processing is established to calculate the temperature distribution of propellant before reaction of motor under slow cook-off. The temperature distribution is used as a parameter to evaluate the response intensity of slow cook-off. The results show that the engine diameter has a great influence on the reaction time and temperature of slow cook off, while the engine length has little effect on them. Both of them have great influence on the reaction position. With the increase in the size and length-to-diameter ratio, the reaction position moves to the edge of the charge. When the size is large enough, the distance between the reaction position and the shell edge remains stable. The mass ratio of high temperature propellant changes with the change of length-to-diameter ratio. When the charge diameter is 150-160 mm, the proportion of high temperature propellant before reaction is the smallest with charges of 5.5 kg, 18.0 kg and 44.0 kg, respectively.

Key words: hydroxylterminatedpolyetherpropellant, slowcook-off, sizeeffect, temperaturedistribution