In the study of noise from propellers and ducted fans, rigorous signal decomposition into harmonic and broadband components is essential for the development of high-fidelity predictive models. Current spectral methods and phase averaging techniques lack the temporal resolution to compensate for fluctuations in operating condition intrinsic to real world experiments. In this paper we use a Vold-...

We report selected carbon species emission indices (EIs) for a Rolls Royce RB211-535-E4 turbofan engine that were acquired during the NASA EXperiment to Characterize Aircraft Volatile Aerosol and Trace-species Emissions (EXCAVATE). Conducted during winter 2002, the mission focused upon characterizing the exhaust constituents of the NASA Boeing 757 aircraft during ground-based operation. Carbon ...

A control software verification framework for gas turbine engines is developed. A stability proof is presented for gain scheduled closed-loop engine system based on global linearization and linear matrix inequality (LMI) techniques. Using convex optimization tools, a single quadratic Lyapunov function is computed for multiple linearizations near equilibrium points of the closed-loop system. Wit...

This paper presents an application of the recently developed theory of language-measure-based discrete event supervisory (DES) control to aircraft propulsion systems. A two-layer hierarchical architecture is proposed to coordinate the operations of a twin-engine propulsion system. The two engines are individually controlled to achieve enhanced performance and reliability, as necessary for fulfi...

We examine the effect of baseline nozzle shape on the ability of fan flow deflectors to reduce downward-emitted turbulent mixing noise of coaxial jets simulating the exhaust condition of a turbofan engine. Several deflector concepts were tested on a nozzle with parallel exit flow lines and a nozzle with convergent flow lines. In every comparison the nozzle with convergent flow lines produced su...