Pretrenched Rotor Stator Tip Clearance Gas Turbine
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Solution Overview
Problem
Gas turbine engine manufacturers seek further improvements in thermal, transfer, and propulsive efficiencies beyond what geared architectures can provide, particularly in the design of the compressor and turbine sections to optimize speed and airflow dynamics.
Innovation Solution
The introduction of a rotor with a pretrench that receives the tip of a stator, where the outer wall of the rotor extends linearly from the base of a rotor blade to the pretrench, and the stator extends radially from outside to inside, creating a configuration that reduces airflow turbulence and increases clearance, allowing for more efficient airflow and reduced axial length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the stator tip clearance is increased to reduce airflow turbulence, then propulsive efficiency is improved, but the axial length of the compressor section increases
Solution Approach 1:
The invention transitions the clearance control from an axial dimension to a radial dimension by introducing a pretrench that extends radially inward from the rotor outer surface. This radial pretrench receives the stator tip, providing clearance control without increasing axial length, thus resolving the contradiction between reducing airflow turbulence and maintaining compact axial dimensions.
Solution Approach 2:
The pretrench creates a localized radial depression at specific circumferential positions where stator tips are received. This local modification provides targeted clearance control exactly where needed at the stator-rotor interface, improving airflow dynamics without requiring global increases in axial length throughout the entire compressor section.
2Loss of energy
If a pretrench is introduced to receive stator tips and improve airflow dynamics, then propulsive efficiency and power density are improved, but the rotor structural complexity increases
Solution Approach 1:
The pretrench design segments the rotor structure by creating distinct radial depressions at specific circumferential positions rather than a continuous complex structure. Each pretrench is a discrete feature that receives individual stator tips, allowing the rotor to maintain simplicity in non-pretrench areas while providing targeted functionality where needed.
Solution Approach 2:
The pretrench extends radially inward to a depth that is sufficient to receive the stator tip and provide the desired clearance control, but does not extend deeper than necessary. This partial action approach provides the minimum required structural modification to achieve airflow benefits without excessive complexity or material removal.
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 airflow dynamics by forming vortices that force airflow radially upward, providing a tighter clearance and improving the overall efficiency and compactness of the gas turbine engine, leading to increased power density and propulsive efficiency.
Implementation Method 1
This configuration enhances airflow dynamics by forming vortices that force airflow radially upward
Data Source
AI summary
A gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, a rotor having a pretrench that receives at least a portion of a tip of a stator, the portion of the tip extending radially into the pretrench.