Study on Control Law for Integrated Variable Geometry Ramjet Engine
A control law design optimization model of supersonic missile/ramjet integration based on energy method is presented.By reasonably adjusting nozzle throat area,inlet subsonic overflow drag is reduced and inlet supersonic pressure recovery coefficient is increased,and specific fuel consumption of the ramjet is reduced,as a result,the missile's total launch weight is reduced.The design optimization model includes a model of predicting the missile lift drag characteristic and a model of computating the ramjet characteristic and installation characteristic,a model of integrating constrain analysis and mission analysis.Composingof missile weight is also taken into account in the design optimization model.The computer program was integrated into iSIGHT software,and the optimization tools of iSIGHT are employed to implement control law design optimization.Computing results of some ramjet engine show that optimally adjusting nozzle throat area can obviously reduce missile launch weight and increase missile maneuverability.