Variable Diffuser Vane Cavities for Compressor Stability

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Solution Overview

Problem

In aircraft environmental control systems, the vanes in variable diffusers of cabin air compressors experience instability and wear due to floating under unstable airflow conditions, leading to dithering, vibration, and potential failure.

Innovation Solution

The vane design includes a body with specific cavities and notches that create a load against the backing plate, preventing free floating and reducing wear by distributing forces uniformly, thus stabilizing the vane during airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If small clearance is provided between the shroud and the vanes and between the shroud and the backing plate, then the variable diffuser can operate with compact dimensions, but the vanes float freely causing dithering, vibration, and resonance under unstable airflow conditions

Engineering Contradiction:

Improvecompact dimensionsVSAvoidvane stability

Core Design Contradiction:

Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies the counterweight principle by creating a load against the backing plate that counteracts the unstable airflow forces. The cavities and notches are designed to generate pressure differential forces that balance the aerodynamic loads, preventing vane flotation and instability while maintaining compact dimensions.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent changes the physical state and distribution of forces within the vane structure by introducing cavities and notches. These geometric modifications alter the pressure distribution and load characteristics, transforming the vane from a freely floating state to a stabilized state with controlled force distribution.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If vanes are held between shroud and backing plate with small clearance, then the variable diffuser structure remains simple, but significant wear occurs between the vanes and the shroud and between the vanes and the backing plate

Engineering Contradiction:

Improvestructure simplicityVSAvoidvane wear resistance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent modifies the force distribution parameters by introducing cavities and notches that create a stabilizing load against the backing plate. This changes the contact mechanics from high-stress point contact to distributed load bearing, significantly reducing wear while maintaining structural simplicity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The cavities and notches act as beforehand cushioning elements that prepare the vane structure to withstand operational loads. By pre-establishing load paths and force distribution mechanisms, the design prevents excessive wear before it occurs during operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If vanes float freely under unstable airflow conditions, then no additional structural elements are needed, but the vanes may dither, vibrate, or resonate leading to potential failure

Engineering Contradiction:

Improvestructural elementsVSAvoidvane failure prevention

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces a counterbalancing load mechanism through the cavities and notches that opposes the destabilizing airflow forces. This creates a force equilibrium that prevents dithering, vibration, and resonance, eliminating the need for additional structural elements while ensuring reliability.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

4Stability of the object's composition

If the vanes are stabilized against the backing plate, then dithering and vibration are prevented, but the design complexity increases with additional cavities and notches

Engineering Contradiction:

Improvevane stabilizationVSAvoidcavities and notches

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the stabilization function with the existing vane structure by integrating cavities and notches directly into the vane body. This combines multiple functions (structural support, load distribution, and stabilization) into a single integrated component, minimizing additional complexity while achieving effective stabilization.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9890793B2Variable diffuser vane

Publication Date: 2018.02.13 HAMILTON SUNDSTRAND CORP

AI summary

A vane for a variable diffuser includes a body with an inlet end and an outlet end, a leading surface extending from the inlet end to the outlet end, a trailing surface opposite the leading surface and extending from the inlet end to the outlet end, a first surface extending from the inlet end to the outlet end, and a second surface opposite the first surface and extending from the inlet end to the outlet end. The vane further includes a first cavity on the first surface of the vane adjacent the inlet end, a second cavity on the first surface of the vane adjacent the outlet end, a third cavity on the second surface of the vane adjacent the inlet end, and a fourth cavity on the second surface of the vane adjacent the outlet end.