Turbomachine Compressor Rotor Guide Wall for Bleed Air Pressure Drop Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current centripetal air sampling methods in turbomachines experience significant turbulence and pressure drops due to air bleed, leading to increased specific consumption and temperature rise, with existing solutions like radial tubes being complex, costly, and heavy.
Innovation Solution
A guide wall is mounted in the chamber between rotor discs, extending along the wall of revolution at a short radial distance to channel air directly to the discs, avoiding jet bursting and vortex formation, and reducing pressure drops by creating Ekman layers with radial air velocities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is bled through through passages in the rotor wall to the annular chamber, then cooling and ventilation of turbine components is achieved, but significant turbulence and pressure drops occur in the annular chamber
Solution Approach 1:
A guide wall is introduced as an intermediary element in the annular chamber to channel and direct the bleed air flow. The guide wall comprises a cylindrical part extending along the wall of revolution at a short radial distance, defining an annular passage that guides air axially from the through passages to one of the rotor discs, preventing direct jet bursting and vortex formation in the chamber
Solution Approach 2:
The invention changes the flow parameters by guiding the air through a controlled annular passage rather than allowing free turbulence in the chamber. This transforms the flow from a high-turbulence state with significant pressure drops to a more controlled axial flow pattern, reducing the pressure drop by up to 50%
2Temperature
If the air entrainment coefficient Ke is increased above 1 to ensure proper turbine cooling, then cooling effectiveness improves, but the flow rate of air drawn off must be increased which raises specific consumption
Solution Approach 1:
The guide wall acts as a mediator that reduces the harmful effects of high rotation speed on the bleed air. By channeling the air through the annular passage and allowing it to form Ekman layers on the rotor discs, the guide wall reduces the relative velocity difference between the air and the rotating discs, thereby reducing the entrainment coefficient Ke and the associated energy losses
3Loss of energy
If radial tubes are mounted in the annular chamber to force air through them, then pressure drops and temperature increase of bleed air are limited, but the fixing means become complex, increasing cost and mass
Solution Approach 1:
The invention extracts and eliminates the complex radial tube assembly and its fixing means from the system. Instead of using radial tubes that require complex vibration-limited mounting, the guide wall provides a simpler, integrated solution that achieves the same flow control objective without the need for additional components or complex assembly procedures
Solution Approach 2:
The guide wall represents a simpler, more economical component compared to the radial tube assembly. It can be manufactured as a single piece or simple assembly that is easier and cheaper to produce, install, and maintain, reducing both initial cost and lifecycle expenses
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 solution reduces pressure drops by up to 50%, allowing air to be bled from a more upstream stage, decreasing specific consumption and temperature, while being simpler, lighter, and less expensive than radial tubes.
Implementation Method 1
The air guided along the wall of revolution then flows naturally along the discs in the direction of the axis of rotation, forming on these discs layers where the air velocities are essentially radial. These layers are related to atmospheric or oceanic phenomena and are called Ekman layers
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Turbomachine compressor rotor comprising at least two coaxial discs (117, 118) carrying blades and connected to one another by an axisymmetric wall (134), and centripetal air bleed means comprising air passages (148) passing through the axisymmetric wall, and a wall (154) extending along the axisymmetric wall from the through-passages as far as one of the discs in order to channel the air flow inside the axisymmetric wall.