Showing papers by "Walter F. O'Brien published in 1995"
TL;DR: In this paper, an active noise control system using a compact sound source is used to reduce aircraft engine duct noise using an adaptive filtered-x algorithm, which is based on an array of identical thin, cylindrically curved panels (125) with an inner radius of curvature corresponding to that of the engine inlet.
Abstract: An active noise control system using a compact sound source is effective to reduce aircraft engine duct noise. The fan noise from a turbofan engine is controlled using an adaptive filtered-x algorithm. Single, multi channel control systems are used to control the fan blade passage frequency (BPF) tone and the BPF tone and the first harmonic of the BPF tone for a plane wave excitation. The multi channel control system is used to control fan tones and a high pressure compressor BPF tone simultaneously, and any spinning mode. A compact sound source is employed to generate the control field. This compact sound source consists of an array of identical thin, cylindrically curved panels (125) with an inner radius of curvature corresponding to that of the engine inlet. These panels are flush mounted inside the inlet duct (Inlet Wall) and sealed on all edges to prevent leakage around the panel.
77 citations
05 Jun 1995
TL;DR: The Joint Dynamic Airbreathing Propulsion Simulations (JDAPS) is a partnership of government, university, and industry organizations for the purpose of developing and applying turbine engine/component numerical simulations to aid in the understand- ing of turbine engine dynamic behavior as mentioned in this paper.
Abstract: The Joint Dynamic Airbreathing Propulsion Simulations (JDAPS) is a partnership of government, university, and industry organizations for the purpose of developing and applying turbine engine/component numerical simulations to aid in the understand- ing of turbine engine dynamic behavior. The primary focus of the simulations being developed by the partnership is to aid in the understanding of gas turbine dynamic behavior such as engine surge, compressor rotating stall, the effects of inlet distortion, and dynamic events during engine start. The insight gained from the development and application of these simulations provides design guidance for improved turbine engine performance and operability. By pooling resources, the organizations involved in the JDAPS partnership have access to more support, both financial and techni- cal, than any one organization could afford on its own. Such syn- ergy makes each organization's return on investment very high.
5 citations
30 May 1995
TL;DR: A plant model is required to design and develop a control system where the device to be controlled is a gas turbine engine as discussed by the authors, which is suitable for the investigation of active controls for preventing instabilities and optimizing performace, especially in aircraft engines in connection with intelligent engine concepts.
Abstract: A plant model is required to design and develop a control system where the device to be controlled is a gas turbine engine. The desirable plant model is a wide-range, high-fidelity model which incorporates the fluid dynamic behavior of the engine internal flows. Such a model can predict the behavior of the engine in stable and unstable regimes; is easily altered to include design changes; and is suitable for the investigation of active controls for preventing instabilities and optimizing performace, especially in aircraft engines in connection with 'intelligent' engine concepts. Models of this kind are presently available and under continuing development. Both compression system and engine models may be constructed as one- or multi-dimensional flow simulations. When such models are linked with control models, a powerful analysis and development tool is produced. The usual control strategies for the stable, normal operating range may be investigated, as well as means to prevent and recover from unstable operation. The mathematical theory of detailed dynamic models is described and examples of specific simulations are given. The application of conventional and advanced control strategies to the simulation is shown by discussion and examples. The advantages of such model-controller combinations are illustrated.