Numerical Investigation Of Blast Deflector Cooling Structure

With the continuous improvement of aircraft engine performance,the thermal shock of blast deflector is also increasing.At present,seawater cooling is used to reduce the temperature of the plate surface subjected to thermal shock,and at the same time,it will cause serious corrosion problems.The air cooling method can effectively avoid corrosion problems,but its cooling efficiency is much lower than that of seawater cooling.In order to solve this problem,in addition to developing a new composite material with deflector plates,the cooling structure can also be optimized to improve the comprehensive heat transfer performance.In this paper,two different cooling schemes are designed for the cooling structure of a blast deflector with air cooling.The computational fluid dynamics(CFD)model is established respectively.The flow and heat transfer characteristics of the cooling structure are numerically calculated,and the influence of the different cooling air inlet on the heat transfer performance is studied.Under the condition of fixed cooling air flow,the inlet angle is optimized by single factor.The influence of inlet angle on internal flow field and temperature field distribution is analysed.The heat transfer performance of the test platform was studied by building a cooling structure test platform.Through comparison and analysis,it is found that the temperature variation trend of the test data is the same as that of the simulation result,and the numerical deviation is less than 20%.The correctness of the numerical calculation model is verified.On this basis,an automatic simulation computing platform integrating Solid Works,ICEM-CFD and Fluent is established by using Isight software.The comprehensive heat transfer performance of the cooling structure(the temperature of the deflector,the temperature of the supporting plate and the outlet temperature of the cooling air)is taken as the objective function.The inlet angle,velocity,outlet width and bracing frame height of cooling air are taken as design variables.Design of experiment was carried out by orthogonal test to study the influence of design variables on objective function.It is found that the inlet angle and velocity have greater influence on the heat transfer performance.Under the appropriate constraint conditions,a multi-objective optimization model is established,and the cooling structure is optimized by genetic algorithm.The results show that,compared with the original cooling structure,the temperature of the deflector plate decreased by 7.1%,the cooling air outlet temperature decreased by14.7%,the support plate temperature decreased by 4.9%,and the internal air temperature decreased by 49.4%.This indicates that the heat transfer performance of the cooling structure has been significantly improved,and an ideal optimization results have been obtained.