Conformal Engine Controller Layout for Smaller Turbofan Nacelles
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Solution Overview
Problem
The challenge in designing turbofan engines is to maximize propulsive efficiency while minimizing the size and weight of the outer nacelle, which is influenced by the radial height of the engine controller, leading to a trade-off between reducing nacelle size and avoiding excessive weight gain.
Innovation Solution
The relationship between the ratio of the engine controller's radial extent to the fan diameter and the normalized radius, represented by the equation 0.1 < Δr/r < K r' - 4/3, guides the design of a conformal engine controller with a minimal radial footprint, optimizing packaging and weight concerns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine controller is positioned within the outer nacelle to maximize propulsive efficiency, then the propulsive efficiency is improved, but the nacelle size and weight increase
Solution Approach 1:
The patent applies parameter changes by establishing specific mathematical relationships between the controller's radial extent (Δr), the fan diameter (r), and the normalized radius (r'). The equation 0.1 < Δr/r < K r' - 4/3 defines optimal parameter ranges that balance propulsive efficiency with weight constraints, allowing designers to select controller sizes that maximize efficiency while staying within weight limits.
2Length of stationary object
If the engine controller's radial extent is reduced to minimize nacelle size, then the nacelle size is reduced, but the controller may become excessively heavy
Solution Approach 1:
The patent uses parameter changes by defining the optimal radial extent of the controller through the relationship 0.1 < Δr/r < K r' - 4/3. This mathematical constraint ensures the controller is compact enough to minimize nacelle size while preventing it from becoming too small and excessively heavy, thus optimizing the weight-size balance.
3Loss of energy
If a larger fan diameter is used to increase propulsive efficiency, then the propulsive efficiency is improved, but the nacelle size increases
Solution Approach 1:
The patent addresses this contradiction by establishing the relationship between fan diameter (r) and the controller's radial extent (Δr) through the equation 0.1 < Δr/r < K r' - 4/3. This allows larger fans to be used for improved propulsive efficiency while the controller dimensions are scaled appropriately to prevent excessive nacelle size increase.
Data Source
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AI summary
A gas turbine engine is provided. The gas turbine engine includes a turbomachine (104); a fan section (102) including a fan (126) rotatable by the turbomachine (104); a nacelle (134) enclosing the fan (126); and an engine controller (150) positioned within the nacelle (134), wherein the nacelle (134) defines an inner surface radius (r) along the radial direction (R) inward of the engine controller (150), wherein the engine controller (150) defines a radial height (Δr) along the radial direction (R), a total volume (V), and a normalized radius (r'), wherein the normalized radius (r') is a ratio of the inner surface radius (r) to the total volume (V) to cube root, and wherein these parameters are related by the following equation: 0.1r′−1<Δrr<Kr′−4/3, wherein the normalized radius (r') is between 1.25 and 8 and K is equal to 40%, or the normalized radius (r') is between 2.75 and 4.5 and K is equal to 65%.