Curved Diffuser Passage for Centrifugal Compressor
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Solution Overview
Problem
Existing diffuser designs for gas turbine engine centrifugal compressors either suffer from excessive trailing edge blockage or inadequate area ratios, leading to impaired performance and increased pressure losses, which affect the efficiency of downstream components.
Innovation Solution
The design incorporates an annular diffuser housing with diffuser flow passages featuring a throat portion and a diffusing section with a centerline that includes both linear and curved portions, allowing for a varying equivalent cone angle along the passage, resulting in a quasi-vaneless annular inlet and circumferentially flared and curved sides to optimize flow distribution and reduce radial envelope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional diffuser designs are used with greater than optimum area ratios, then trailing edge blockage is reduced, but downstream component performance is impaired due to large trailing edge blockages
Solution Approach 1:
The patent applies parameter changes by varying the equivalent cone angle along the diffuser passage length. The diffuser passage is designed with a non-uniform expansion profile where the equivalent cone angle changes continuously from upstream to downstream, allowing optimization of both area ratio and trailing edge blockage simultaneously. This gradual, controlled expansion maintains favorable flow conditions while achieving the desired balance between area ratio and trailing edge blockage.
2Stress or pressure
If diffuser passages are designed to improve aerodynamic performance, then static pressure rise increases, but the radial envelope of the engine increases
Solution Approach 1:
The patent employs curvature by designing the diffuser passage with a curved centerline and varying cross-sectional geometry. The passage follows a curved path with optimized curvature radius that allows the flow to turn smoothly while expanding. This curved configuration enables compact packaging within a smaller radial envelope while maintaining effective diffuser length and achieving high static pressure rise through optimized flow turning.
Solution Approach 2:
The patent utilizes three-dimensional diffusion by varying the passage geometry in multiple dimensions. The diffuser passage expands not only in the radial direction but also in the axial and circumferential directions, creating a complex 3D flow path. This multi-dimensional expansion allows efficient diffusion of the flow while keeping the overall radial envelope compact, as the area increase is distributed across multiple spatial dimensions rather than requiring large radial growth.
Data Source
AI summary
A diffuser for a centrifugal compressor including an annular diffuser housing having a plurality of diffuser flow passages therethrough the housing. Each passage including a throat portion and a diffusing section with upstream and downstream diffusing portions. A diffusing passage centerline includes a linear portion extending downstream through the throat portion and the upstream diffusing portion and a curved portion of the diffusing passage centerline extending downstream from the centerline linear portion through the downstream diffusing portion. The diffuser flow passages may have an equivalent cone angle varying non-linearly or more particularly curvilinearly downstream along curved portion. The downstream diffusing portion may be flared.