Numerical Simulation Study Of Solid Rocket Motor High Temperature Gas Cooling System

With the increasing demand for space exploration in the world,solid rocket has become one of the key points in the development of major aerospace countries because of its fast response,strong mobility,low cost and high reliability.As the core of the solid rocket engine,its development and manufacturing has become a priority.Ground ignition test is also an essential part in the development of solid rocket motor.For ground ignition tests of different solid rocket motors,the temperature of nozzle inlet can usually reach above 3000 K.And the high-temperature gas will radiate a lot of infrared energy into the space.Therefore,water jet cooling method is planned to reduce the temperature of the heat source,that is,the intensity of infrared radiation is reduced from the source.Therefore,the effective cooling treatment of high temperature gas is of great significance.However,relevant research on water-jet cooling of rocket engine test stands at home and abroad has focused on the thermal protection.The numerical simulation and test to reduce the overall temperature of exhaust gas to achieve the purpose of concealed test have not been formally carried out.In this paper,the cooling treatment is carried out by installing a water spray in the expansion section to study the interaction between the two phases.The flow field simulation is carried out by commercial computational fluid dynamics software using SST K-Omega,DPM,component transport and other models.The main tasks are as follows:Firstly,through one-dimensional theoretical calculation,reasonable initial values of relevant design parameters are provided for the subsequent numerical simulation study of high-temperature gas jet cooling.In order to prove the feasibility of water spraying on gas cooling,numerical simulation of gas jet without water spraying and water spraying was conducted for a certain type of solid rocket engine.By comparing and analyzing the outlet temperature and flow field cloud diagram,the feasibility of the water jet cooling method for high temperature and high speed gas cooling is illustrated.The calculation results show that the high temperature above 3000 K at the nozzle inlet is reduced to 400 K by water spray cooling,and will not have an unnecessary impact on the test flow field of the nozzle outlet.By changing the injection angle,injection area,spray velocity and flow of cooling water,a large number of numerical simulation studies on optimization of design parameters of gas cooling were conducted.It provides the theoretical and simulation basis for the later experiment,and provides a reasonable solution.Research finding:The cooling effect is best when the injection angle is perpendicular to the flow,and the temperature distribution at the outlet is more uniform than the other angles.Jet injection at the angle perpendicular to the wall or the incoming flow has little different on the distribution of outlet temperature and the overall cooling effect of the gas.Spraying water at a certain angle before or after tilting does not improve the cooling effect,and most of the particles are concentrated near the wall,thus reducing the overall cooling effect of the gas.However,if there is a need for wall protection,this method can be considered.In the case of a certain flow rate,there is a more suitable flow rate to achieve a better cooling effect.Too large or too small injection speed will not improve the overall cooling effect of the gas temperature,but will aggravate the uneven distribution of the gas temperature.In the case of a certain flow rate,there is a more appropriate flow rate,can get the most uniform temperature distribution,is also a better cooling effect.Large or small injection speeds do not improve the overall cooling effect of the gas temperature.On the contrary,it will increase the non-uniformity of gas temperature distribution.Under the appropriate water spraying speed,water spraying flow is the most influential factor among the three influencing factors discussed in this paper.Increasing the flow rate by increasing the flow rate or the area of the jet leads to a further drop in temperature,but with the increase of flow rate,the vaporization rate of water will decrease,and the increase of flow rate will increase the inhomogeneity of temperature distribution.