Dual combustor ramjet engine dynamics modeling and simulation for design analysis

Abstract

An integrated low-order, medium-fidelity model for a dual combustor ramjet engine configuration is derived for use in mission analysis and controller design. Each of the individual components – intake, isolator, ram diffuser and combustor, scram combustor and nozzle – are modeled using either empirical data or analytical relations, or in case of the two combustors by using a quasi-one-dimensional code. The components are appropriately linked to capture the key physical phenomena inherent in the dual combustor ramjet engine operation and the ongoing dynamic processes. Feedback loops due to the upstream influence of the pressure and time lags due to acoustic and flow-related delays are modeled. Sample results are generated for a dual combustor ramjet engine configuration with Jet-A fuel at a design condition of Mach 7 at 27.5 km altitude, and stability and dynamic behavior, steady-state performance, and response to fuel throttling input are assessed. Its low order and the ability to be easily reconfigured for a new geometry/parametric input make the model useful for mission analysis studies with a quick turn-around time.