Components level mathematical model of two-stage turbocharging reciprocating engine propeller propulsion system and analysis of its flying characteristic

A flying characteristic simulation method was studied for two-stage turbocharging reciprocating engine propeller propulsion system suitable for medium/high altitude low-speed long-endurance multi-role aerial vehicle systems at 10-20 kilometers height. With introduction of the simulation method for gas turbine engine with component models, and based upon component maps or algebraic equations, this method solved joint-working equations of the propulsion system by Newton iteration method to obtain co-operation points of the system. A full-power holding requirement and turbocharger-engine collaboration condition were stated. The regulating rules in both full-power holding mode and power lapse mode were analyzed. The influences of regulating rules on turbocharger operating lines were discussed. Finally, the altitude-velocity characteristics of the propulsion system and components were investigated. The research shows three results. This method enables rapid convergence and usually needs only 5-6 iterations to obtain one operating point. The regulation scheme of two gas-bypass valves can not only meet the design objectives, but also allow effective adjustment to the operating points of the turbochargers. This method can be extended conveniently to the simulations of more complex multi-stage turbocharging systems.