Non-Axially Symmetric Fan End Wall Modeling
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Solution Overview
Problem
Existing end wall modeling methods for fan assemblies in aero engines are inefficient due to long optimization times, complex surface generation, and failure to consider combined designs with blades and spinners, leading to increased loss and stall risk.
Innovation Solution
A modeling method that constructs non-axially symmetric end wall curved surfaces in a cascade channel using a flow path design method for a dual flow path of a blade end area, determining initial axially symmetric and recessed curve radii, and employing a multi-segment concave curve modeling method to integrate blade, end wall, and spinner designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional axially symmetric end wall is used, then the design is simple and manufacturing is easy, but secondary flow increases causing increased loss and stall risk
Solution Approach 1:
The patent applies asymmetry by transitioning from an axially symmetric end wall to a non-axially symmetric end wall design. The end wall curve is divided into multiple sections with different curvature characteristics, where the curvature radius varies along the axial direction to control secondary flow. This asymmetric design reduces end wall loss and improves stall margin by optimizing the flow field distribution in the end area.
2Manufacturing precision
If numerical optimization method is used for end wall modeling, then optimal curved surface can be found, but optimization time is long and generated surface is complicated
Solution Approach 1:
The patent applies preliminary action by pre-defining the end wall curve structure with specific control points and curvature characteristics before optimization. The method establishes a parametric model with predetermined geometric features that guide the optimization process, avoiding random search and reducing optimization time while ensuring manufacturing precision.
Solution Approach 2:
The patent segments the end wall curve into multiple sections with different curvature characteristics. Each section is defined by control points that can be independently adjusted, allowing localized optimization without complicating the overall surface generation. This segmentation approach simplifies the optimization process while maintaining manufacturing precision.
3Productivity
If end wall modeling is performed without considering blade and spinner combination, then end wall design is simplified, but airflow becomes unsmooth reducing efficiency and stall margin
Solution Approach 1:
The patent merges the end wall design with blade and spinner configurations into an integrated modeling approach. The non-axially symmetric end wall curve is designed in coordination with blade root geometry and spinner shape, ensuring smooth airflow transition across all components. This combined design optimizes the flow field in the end area, improving efficiency and stall margin while accounting for the interactive effects of all components.
Data Source
AI summary
A modeling method for a fan assembly includes-comprises constructing non-axially symmetric end wall curved surfaces in a cascade channel. Constructing the non-axially symmetric end wall curved surfaces in the cascade channel includes: determining, using a flow path design method for a dual flow path of a blade end area, an initial axially symmetric curve radius and a recessed curve lowest point radius of non-axially symmetric curved surfaces; and constructing the non-axially symmetric end wall curved surfaces in the cascade channel according to the initial axially symmetric curve radius and the recessed curve lowest point radius. The modeling method constructs the non-axially symmetric end wall curved surfaces in the cascade channel using the flow path design method for a dual flow path of a blade end area, to implement the control of flow directions by the non-axially symmetric curved surfaces, thereby reducing end wall loss.