Single stage, low noise, advanced technology fan. Volume 1: Aerodynamic design

The aerodynamic design for a half-scale fan vehicle, which would have application on an advanced transport aircraft, is described. The single stage advanced technology fan was designed to a pressure ratio of 1.8 at a tip speed of 503 m/sec 11,650 ft/sec). The fan and booster components are designed in a scale model flow size convenient for testing with existing facility and vehicle hardware. The design corrected flow per unit annulus area at the fan face is 215 kg/sec sq m (44.0 lb m/sec sq ft) with a hub-tip ratio of 0.38 at the leading edge of the fan rotor. This results in an inlet corrected airflow of 117.9 kg/sec (259.9 lb m/sec) for the selected rotor tip diameter if 90.37 cm (35.58 in.). The variable geometry inlet is designed utilizing a combination of high throat Mach number and acoustic treatment in the inlet diffuser for noise suppression (hybrid inlet). A variable fan exhaust nozzle was assumed in conjunction with the variable inlet throat area to limit the required area change of the inlet throat at approach and hence limit the overall diffusion and inlet length. The fan exit duct design was primarily influenced by acoustic requirements, including length of suppressor wall treatment; length, thickness and position on a duct splitter for additional suppressor treatment; and duct surface Mach numbers

Curved centerline air intake for a gas turbine engine

An inlet for a gas turbine engine was disposed about a curved centerline for the purpose of accepting intake air that is flowing at an angle to engine centerline and progressively turning that intake airflow along a curved path into alignment with the engine. This curved inlet is intended for use in under the wing locations and similar regions where airflow direction is altered by aerodynamic characteristics of the airplane. By curving the inlet, aerodynamic loss and acoustic generation and emission are decreased

Preliminary Design of Low Cost Propulsion Systems Using Next Generation Cost Modeling Techniques

Introduction At GE Aircraft Engines (GEAE), during the preliminary design process for aircraft propulsion systems, the designer has always been concerned about the cost implications of engine architecture and material requirements, which are driven by design specified engine thermodynamic operating conditions. The concern was not only about initial acquisition economics, but about maintenance costs associated with the propulsion life cycle as well as the development costs associated with design and certification of the power plant. The difficulty has been that there was no rapid, accurate cost estimating process to allow the designers ready access to the cost implications of design choices. High cycle pressure ratios and bypass ratios were thermodynamically attractive in reducing SFC. Technology, whether in the form of complex aerodynamic blade shapes to increase efficiency or higher temperature materials to reduce undesirable effects of cooling flows on SFC, was considered without in depth quantitative cost impacts of these design choices. Unprecedented levels of airline financial losses in the early 1990s provided a clear focus, for both current and future products, indicating cost is a key discriminator. Airline customers demanded engines that are affordable both to buy and to own. Clearly a need had been established to quickly and accurately understand the cost and life implications of preliminary design choices. Examination of cost models, both inside and outside the company, failed to locate a generic model which satisfied GEAE business needs; i.e., one tha

PRELIMINARY DESIGN OF LOW COST PROPULSION SYSTEMS USING NEXT GENERATION COST MODELING TECHNIQUES

GE Aircraft Engines, Cincinnati, Ohio 111111111111111111111 III utilized current production costs for parts and was tied to a system which was periodically updated costed development and certification program associated with engine design choices reflected the impact of thermodynamic design choices on maintenance cost associated with long term product utilization. The technical challenge had been established and GEAE launched an initiative in the early 1990's to produce such a code. This paper presents trade studies considering engine cycle trades with cost as a key discriminator. INTEGRATED PRELIMINARY DESIGN SYSTEM To function in a manner which provides rapid response and system optimization, a preliminary design tool set, capable of being integrated, is required. The specific needs are linkable models which define: • parametric engine cycle performance • parametric engine weight • engine cost • NC mission analysis Ideally these programs would be linked and on-line user specified inputs would generate real time system impacts and interdependencies. At a minimum, the programs must provide input to each other with minimal user intervention. Emission and noise considerations must also be assessed in any actual product study. For the purpose of brevity and relative simplicity the emission and acoustic effects are not considered for the study presented here. The preliminary design system currently in use at GEAE has the above linkable tool se