Study On The Effect Of The Number And Distribution Of Spoiler On The Fuel Regression Rate Of Hybrid Rocket Motor

Hybrid rocket motor has many advantages,such as safety,environmental protection,grain stability and so on.It has great potential in motorering application,but the thermal decomposition rate of solid fuel of hybrid rocket motor is low.In order to improve the thermal decomposition rate of solid fuel,it is a common method to use spoiler to reduce the gas velocity in combustion chamber and increase the thermal decomposition rate of solid fuel.In this paper,hydrogen peroxide/hydroxyl-terminated polybutadiene(HTPB)propellant is used as oxygen-burning agent combination,and two-dimensional axisymmetric integrated numerical simulation is used to simulate hybrid rocket motors with different internal spoiler diameter difference,different number and distribution of internal spoiler,The number and distribution of internal spoiler in hybrid rocket motors are studied to the thermal decomposition of solid fuel in hybrid rocket motors,and provides a theoretical basis for the design of solid-liquid rocket motor.The fuel regression rate calculation of hybrid rocket motor structures with built-in spoiler diameter difference of 2.25_hD,2.5_hD,2.75_hD,3.0_hD and 3.25_hD is carried out.The results show that the thermal decomposition rate of solid fuel increases first and then decreases with the increase of the internal and external diameter difference of the built-in spoiler.The thermal decomposition rate of hybrid rocket motor fuel with built-in spoiler and without built-in spoiler structure is compared.Under the same boundary conditions,the thermal decomposition rate of the former is significantly increased.When the inner diameter of the internal spoiler is 3.0,the maximum efficiency is increased by 26.55%.The single built-in spoiler structure divides the wall regression rate rate of solid fuel into two regions.The thermal decomposition rate of the front part of the spoiler plate is slightly lower than that without the built-in spoiler.The thermal decomposition rate of fuel behind the spoiler plate increases dramatically,and then decreases along the axis until it reaches the level in front of the spoiler plate.As the position of the built-in spoiler moves along the axis from the nozzle inlet,the average thermal decomposition rate of solid fuel in hybrid rocket motor increases first and then decreases.The maximum value is that the spoiler is located in the front of the grain about 30%,and the closer the spoiler is to the position,the higher the average regression rate is.The solid fuel wall regression rate is divided into three parts by two built-in spoiler plates.The solid fuel regression rate of the combustor with the first built-in spoiler plate is lower than that without the spoiler plate;the grain regression rate of the rear part of the two built-in spoiler plates is obviously increased and gradually decreased along the transverse axis direction;when the distance between the two built-in spoiler plates is close,the solid fuel wall regression rate of the combustor with the first built-in spoiler plate is lower than that without the The solid grain regression rate rate caused by the first spoiler has not been reduced to the level before the plate,and then the spoiler is used to increase the subsequent solid grain regression rate rate,which leads to the low average grain regression rate rate.When the second spoiler is too far behind,because the solid grain behind the spoiler in the combustion chamber is too short,the vortex behind the spoiler plate can not fully play its role,resulting in the average grain.This caused the regression rate to low.The three built-in spoiler structures divide the solid fuel wall regression rate rate into four parts.The first built-in spoiler plate has a lower solid fuel regression rate rate than the combustion chamber without spoiler plate structure.The grain regression rate rate of the rear part of the three built-in spoiler plates has a significant increase and gradually decreases along the transverse axis.The higher the wave peak is near ?_d=0.33,the higher the spoiler plate is.The farther away,the lower.Therefore,when the position of the first spoiler is fixed,the subsequent spoiler should be located at the back of the equal position of the grain behind the first spoiler,so that the minimum value behind each spoiler plate is equal.At this time,the overall regression rate of solid fuel grain is the largest.