Supersonic mixed-compression inlet modeling for control applications.

摘要

Simulation of high speed propulsion systems may be divided into two categories, nonlinear and linear. The nonlinear simulations include simulations based on computational fluid dynamics (CFD) methodologies. These simulations tend to provide high resolution results that show the fine detail of the flow. Consequently, the simulations are large, numerically intensive, and run much slower than real-time. Linear models are generally used during the preliminary stages of control design. These simplistic models often run at or near real-time but do not always capture the detailed dynamics of the flow configuration. The main contribution of this research is a new methodology that can be used to generate linear models from quasi-one-dimensional and multi-dimensional steady-state CFD results. This method provides a small perturbation model that can be used for control applications and real-time simulations. It is important to note the utility of the modeling procedure; all that is needed to obtain a linear model of the propulsion system are the governing equations, the spatial step, geometry, and steady-state operating conditions from a CFD simulation or experiment. Several examples are included that illustrate the utility of the methodology. This research represents an important step in establishing a bridge between the controls discipline and the CFD discipline so that the control engineer is able to effectively use CFD results in control system design and analysis.