Fans, Compressors, and Turbines EGR 4347 Analysis and Design of Propulsion systems

General Electric CF6-50

CFM-56

F100-PW-220 Turbofan Engine

F-404 vs. J79

GP 7200 – GE and P&W For Airbus 380

Bird Strikes

Results

Compressors AXIAL CENTRIFUGAL

Axial Compressor

Complex Flow in Compressors General Electric

This 4-stage ATEGG Compressor Rig, the highest loaded compressor ever built with acceptable stall margin and efficiency characteristics, meets the Phase III stage loading goals. JTAGG III Advanced Concept Centrifugal Impeller with independent inducer and exducer will provide higher pressure ratio and efficiency. Integrating Forward Sweep and Splitter Technology are key features to achieving high efficiency and high pressure ratio. This stage will be utilized as the JTAGG III low pressure compressor. JTDE Forward Swept Fan Blisk will be the first large forward swept rotor to be tested in a demonstrator engine. A Forged Orthorhombic Transformed Super Alpha-2 Billet will be bonded to Gamma TiAl to form a novel, dual alloy impeller. tet/brochure/Materials.htm The compression systems of tomorrow's aircraft gas turbine engines must have reduced weight, provide higher performance, and be more robust in order to develop pressures of up to seventy atmospheres to meet IHPTET Phase III goals. Significant progress has already been achieved through the application of advanced Computational Fluid Dynamics (CFD) analysis tools, innovative aerodynamic and mechanical design schemes, and high specific strength material systems. Aerodynamic sweep and "splittered" rotor designs provide higher pressure ratios and efficiencies with a significant improvement in stability margin. A Phase III two stage fan combined with a four stage compressor will provide the same performance as the three stage fan and ten stage compressor in the F100 engine, dramatically reducing the number of parts while meeting Phase III production and maintenance cost goals. Hollow fan blades and organic and metal matrix composite rotating and static structures significantly reduce weight. The core driven fan enables the variable cycle engine to operate as a turbofan or turbojet, vastly broadening operational capability. Rotor and stator airfoil designs, analyzed with advanced unsteady aerodynamic analysis codes, reduce aeromechanical design iterations which reduce design costs while increasing correctness. Numerous compression system designs have been tested and analyzed at the Air Force Research Laboratory's Compressor Research Facility (CRF) and Compressor Aero Research Lab (CARL).

TURBINES PURPOSE: Convert KE into shaft HP ENVIRONMENT: –Favorable Pressure Gradient more turning, more work per stage relative to compressor –Temps exceed material limits; cooling reqd –High stresses due to temp and rotation –Fixed geometry –3/4 of energy available after combustor used to drive compressor

Parameters Affecting Turbine Blade Design Vibration Environment Tip Shroud Inlet Temperature Blade Cooling Material Number of Blades Airfoil Shape Trailing-Edge Thickness Allowable Stress Levels (AN 2 ) (N = Speed, RPM) Service Life Requirements

TURBINE ANALYSIS - Velocity Triangles

TURBINE COOLING WHY? TYPES OF DESIGNS EFFECTIVENESS THERMAL BARRIER COATING

WHY? Combustor gas temps exceed metal melting temps To increase thrust-to-weight, temps increase faster than material capability High metal temps weaken blade/reduce life Cooling air can be distributed to reduce large temperature gradients (reduces thermal fatigue) - if not done properly, the reverse can happen

TURBINE COOLING

Castcool® High and Low Pressure Turbine Blades for ATEGG and JTDE will demonstrate capability at conditions more than 100°F above the Phase II turbine temperature objective. Improved Thermal Barrier Coatings which have reduced conductivity and weight will enable this turbine blade to meet Phase II and III turbine temperature goals. High Work Turbine Design demonstrates Phase II performance and cooling technology in rig and JTAGG I engine testing using advanced aerodynamics and cooling schemes in diffusion bonded airfoils. Modern turbines must maintain a balance between high performance, affordability, and design robustness in order to maximize engine payoff. Achieving production part cost, along with substantially improved life-cycle costs, requires development of significantly enhanced manufacturing techniques; strong, low density, affordable materials; and the use of concurrent engineering practices from initial design concept to "fielding" of the part. Development for component robustness and a need for long intervals between inspections and overhauls require parts with improved fatigue behavior. High performance cooling technologies will maximize the effectiveness of reduced cooling flows while improving life through the application of novel structural designs. Special emphasis is placed on enhanced analysis techniques, including 3-D time accurate computational codes, to provide better understanding of the aerodynamic and heat transfer mechanisms occurring in extremely complex airfoils. Using the Air Force Research Laboratory 's Turbine Research Facility (TRF), advanced, short duration test methods are being applied to validate turbine aerodynamic and cooling designs. These test methods will be extended to measure turbine structural dynamics and high cycle fatigue characteristics.