Contra-Rotating Turbine Cavity Segmentation for Cooling Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cooling devices for contra-rotating turbines, such as LPTACC, are ineffective due to the formation of a boundary air layer around rotating drums, reducing cooling efficiency and increasing compressor efficiency penalties.
Innovation Solution
The implementation of a turbine design featuring upstream and downstream annular cavities separated by sealing means, with the upstream cavity supplied with high-pressure cooling air for purging and pressurization, and the downstream cavity supplied with lower-pressure cooling air for efficient cooling of the rotors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single annular cavity is used for cooling the contra-rotating turbine, then the structure is simpler, but the cooling efficiency is reduced due to the piston effect and boundary layer formation
Solution Approach 1:
The single annular cavity is divided into two separate cavities: an upstream annular cavity and a downstream annular cavity, separated by a sealing means. This segmentation allows independent pressure control in each cavity, eliminating the piston effect that occurred in the single-cavity design and improving cooling efficiency.
2Reliability
If high-pressure cooling air is supplied to the entire annular space, then the purging effect is improved, but the compressor efficiency penalty increases
Solution Approach 1:
Different pressure levels of cooling air are supplied to different regions: high-pressure cooling air is supplied only to the upstream annular cavity where purging is needed, while lower-pressure cooling air is supplied to the downstream annular cavity. This local differentiation maintains effective purging while reducing the overall compressor efficiency penalty.
3Ease of operation
If cooling air is supplied without pressure differentiation, then the system is simpler to operate, but the clearance control precision is reduced
Solution Approach 1:
The system dynamically adjusts the pressure of cooling air supplied to different cavities based on operational requirements. The upstream cavity receives high-pressure air for effective purging, while the downstream cavity receives lower-pressure air for precise clearance control, enabling adaptive optimization of both purging and clearance management.
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 design effectively reduces the air temperature felt by the outer annular drum, minimizes the 'piston' effect, and achieves active control of clearances in the turbine, thereby enhancing overall turbine efficiency and longevity.
Implementation Method 1
the upstream annular cavity being connected to first means for supplying cooling air at a first pressure
Implementation Method 2
cooling air can enter the manifold housings 22 then into the tubes 23 before coming out through the orifices opposite the casing 18, so as to cool it
Implementation Method 3
one upstream annular cavity and one downstream annular cavity separated from each other by sealing means
Data Source
AI summary
A turbine has a first rotor and a second rotor configured to pivot about a longitudinal axis (X) according to two opposite directions of rotation. The first rotor has a radially outer drum from which blades extend radially inwards. The first rotor and the second rotor are surrounded by a stator annular part. The stator annular part delimits, with the drum, at least one upstream annular cavity and one downstream annular cavity separated from each other by sealing means.