Papers by Keyword: Aircraft Engines

Abstract: The data processing of static engine noise test, especially the elimination of ground reflection to access the free-field sound pressure level, has been defined as one of the basic steps in aircraft noise prediction on the noise certification procedure by ICAO^[1,. Based on the importance of the method, this paper will study the impact of the ground reflection effects on the aircraft engine noise experimental, especially made a detailed overview for the calculation method of reflective index.This paper also gives the method of fixing this effect to get the free field sound pressure level, while making experiments to verify the feasibility of this method, so that make the noise analysis and prediction according to the noise certification procedures.

Abstract: Product performance including the cost of ownership is becoming increasingly dependent on the availability of high quality, high performance, affordable materials of construction. Today, the requirements placed on a new material for a high performance structural application extend well beyond the improvement of one or more material properties. This makes the introduction of a new material a multi-faceted activity. Modern structural materials derive their performance from a combination of composition and processing, the results of which are inextricably intertwined. This statement pertains to both metallic alloys and to fiber reinforced composite materials. In addition, material cost and the reproducibility of material properties are becoming more central as acceptance criteria for incorporating new materials into new products. This paper will use examples of recent developments in materials for aircraft gas turbines to depict the materials introduction process. Some of these developments have been successful and others have not. These examples illustrate the changing picture that represents the successful introduction of a new structural material, even in a high performance, high value product such as a gas turbine. Specific examples will include metal matrix composites, Ni-base alloys and improved reliability Ti alloys. The basis for successful introduction, or lack thereof will be discussed. While the examples are specific to gas turbines, they are generally instructive and depict the growing complexity of the process of developing and introducing new materials into a high value product. An additional issue for all new materials introduction is the time required to achieve product readiness. As the time required for product design decreases, there has been little commensurate reduction in materials development cycle time. This matter also will be discussed and some possible reasons and potential solutions will be described.