Compressor Vane Dihedral and Sweep Profile for Tip Sealing
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Solution Overview
Problem
Gas turbine engine compressor vane designs face inefficiencies due to traditional sealing systems and interstage sealing challenges, which affect performance and manufacturing efficiency.
Innovation Solution
The design incorporates rotor disks with spacers and stator vanes featuring airfoils with a specific dihedral and sweep profile, including a leading edge sweep of 25-45° and dihedral of 30-60°, which reduces tip-to-spacer clearance impact and improves airflow by pulling more airflow to the tip region, thereby reducing pressure loss and increasing flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sealing systems with abradable seal material and knife edge runners are used, then sealing between rotor and stator is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent removes the traditional knife edge runners and abradable seal material from the stator vane assembly, extracting the sealing function entirely. The spacer is designed to run directly against the rotor blade tips without any additional sealing components, simplifying the sealing system while maintaining effectiveness through the centrifugal compression mechanism.
Solution Approach 2:
The sealing system becomes self-regulating through centrifugal force. As the rotor spins, centrifugal action automatically compresses the rotor blade tips against the spacer, maintaining the sealing gap without requiring external adjustment or complex mechanical sealing components. The system self-adjusts to operational conditions.
2Ease of manufacture
If compressor vanes have traditional airfoil profiles, then manufacturing is simplified, but pressure loss increases and flow momentum decreases
Solution Approach 1:
The patent modifies the airfoil geometry parameters, specifically implementing a swept leading edge and dihedral angle at the tip region. These parameter changes optimize the airflow characteristics, reducing pressure loss and improving flow momentum while maintaining manufacturability through standard aerospace manufacturing techniques.
3Loss of substance
If tip-to-spacer clearance is reduced to improve sealing, then leakage decreases, but manufacturing precision requirements increase
Solution Approach 1:
The patent transitions from a static clearance design to a dynamic sealing mechanism. The spacer and rotor blade tips are designed to maintain contact or near-contact through centrifugal compression during rotation, dynamically adjusting the effective clearance based on operational speed rather than relying on fixed manufacturing tolerances.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances overall performance by reducing pressure loss and increasing flow momentum, particularly at stall conditions, and maintains higher momentum near the tip region, leading to improved efficiency and reduced leakage.
Implementation Method 1
airfoils with inboard tips in facing proximity to an outer surface of a first of said spacers; characterized in that the airfoils have a dihedral and sweep profile characterized by: leading edge sweep of 25 - 45° along a first region of at least 10% of total span starting within 5% of the tip; and dihedral of 30 - 60° along a second region of at least 10% of total span starting within 5% of the tip
Implementation Method 2
With the rotor rotating, a centrifugal action may maintain longitudinal rotor compression and engagement between a spacer and at least one of the adjacent disks
Data Source
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AI summary
A gas turbine engine rotor stack (44) includes one or more longitudinally outwardly concave spacers (62). Outboard surfaces of the spacers (62) may be in close facing proximity to inboard tips of vane airfoils (50). The airfoils have a dihedral and sweep profile.