![]() ![]() Airfoils are generally designed for a specific flight condition and, therefore, are not fully optimized in all flight conditions. Of the factors that mainly affect the efficiency of the wing during a special flow regime, the shape of its airfoil cross section is the most significant. +-.0.150 inches in directions normal to the surface of the airfoil.ĭesign of a shape adaptive airfoil actuated by a Shape Memory Alloy strip for airplane tail The nominal airfoil given by the X, Y and Z distances lies within an envelop of. The X and Y distances may be scalable as a function of the same constant or number to provide a scaled up or scaled down airfoil section for the bucket. The profile sections at each distance Z are joined smoothly to one another to form a complete airfoil shape. The X and Y values are distances which, when connected by smooth continuing arcs, define airfoil profile sections at each distance Z. Third stage turbine buckets have airfoil profiles substantially in accordance with Cartesian coordinate values of X, Y and Z set forth Table I wherein X and Y values are in inches and the Z values are non-dimensional values from 0 to 0.938 convertible to Z distances in inches by multiplying the Z values by the height of the airfoil in inches. Hyde, Susan Marie By, Robert Romany Tressler, Judd Dodge Schaeffer, Jon Conrad Sims, Calvin Levy Application of these conditions to the QAT fan blade and engine cycle was estimated to result in an overall fan efficiency gain of 0.4 percent. Constraints related to flight safety and failed mode operation suggest that use of the baseline blade shape with actuation to the optimum cruise condition during a portion of the cycle would be likely required. A high-level aerodynamic assessment using a GE90-90B Block 4 engine cycle and fan blade geometry indicates that blade camber changes of approximately +/-4deg would be sufficient to result in fan efficiency improvements nearing 1 percent. Based on perceived contributions to improving engine efficiency, the fan blade was chosen as the primary application for a more detailed assessment. Three general categories of potential components were considered-fan blades, booster and compressor blades, and stator airfoils. Scoping of shape changing airfoil concepts including both aerodynamic analysis and materials-related technology assessment effort was performed. Also, this method is flexible and extendible to a larger class of requirements and changes in constraints imposed. This method determines a robust, optimal, subsonic airfoil shape, beginning with an arbitrary initial airfoil shape, and imposes the necessary constraints on the design. A perturbation procedure provides a class of airfoil shapes, beginning with an initial airfoil shape.Ī method has been developed to create an airfoil robust enough to operate satisfactorily in different environments. The resulting design is robust against variations in airfoil dimensions and local airfoil shape introduced in the airfoil manufacturing process. Method system, and product from application of the method, for design of a subsonic airfoil shape, beginning with an arbitrary initial airfoil shape and incorporating one or more constraints on the airfoil geometric parameters and flow characteristics. In particular, we obtain and interpret a two-dimensional approximation of both transonic lift and drag, and we show how these approximation inform a multi-objective design problem. The active subspaces enable low-dimensional approximations of lift and drag that relate to physical airfoil properties. ![]() We mathematically relate the two parameterizations with a common polynomial series. We examine two particular airfoil shape parameterizations, PARSEC and CST, and study the active subspaces present in two common design quantities of interest, transonic lift and drag coefficients, under each shape parameterization. Airfoil design in a transonic flow field with a parameterized geometry is a popular test problem for design methodologies. This low-dimensional structure provides insights that characterize the dependence of quantities of interest on design variables. A low-dimensional active subspace, when present, identifies important directions in the space of design variables perturbing a design along the active subspace associated with a particular quantity of interest changes that quantity more, on average, than perturbing the design orthogonally to the active subspace. Active Subspaces of Airfoil Shape Parameterizationsĭesign and optimization benefit from understanding the dependence of a quantity of interest (e.g., a design objective or constraint function) on the design variables. ![]()
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