Rail Member Flow Control Assembly for Turbine Tip Clearance
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Solution Overview
Problem
High tip clearance between the rotor and turbine casing in gas turbine engines leads to significant energy loss, as high-energy fluid escapes without generating useful power, constituting a major source of loss in turbine stages, and reducing this clearance increases the risk of interference between components.
Innovation Solution
A flow control assembly with a wall and member configuration that includes a first and second chamber, where the rail member diverts the fluid path into a curved configuration and the second chamber directs it into a vortex configuration, reducing the effective clearance gap and minimizing energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the physical clearance between the turbine casing and rotating blade is reduced, then tip clearance loss is reduced, but the risk of interference or rubbing between components increases
Solution Approach 1:
The invention divides the flow control function into two separate components: a rail member that reduces the physical clearance gap and a flow diverting member that actively redirects fluid flow. This segmentation allows the rail member to minimize clearance while the flow diverting member prevents harmful leakage, resolving the contradiction between reducing energy loss and maintaining reliability.
Solution Approach 2:
The flow diverting member acts as an intermediary element between the rail member and the turbine casing. It redirects the fluid flow path so that high-energy fluid does not directly escape through the clearance gap, thereby reducing tip clearance loss without requiring the clearance to be physically reduced to the point of causing component interference.
2Loss of energy
If a duel vortex chamber is employed in the turbine casing to reduce effective clearance, then tip clearance flow is reduced, but implementation difficulty increases due to aerodynamic issues
Solution Approach 1:
Instead of modifying the turbine casing to include a complex duel vortex chamber, the invention extracts the flow control function and implements it through simpler components attached to the rotor: a rail member and a flow diverting member. This extraction approach achieves the same effect of reducing tip clearance flow while avoiding the aerodynamic issues and implementation complexity associated with modifying the turbine casing.
Solution Approach 2:
Rather than attempting to create vortex flows within the turbine casing (stationary component), the invention inverts the approach by implementing flow control features directly on the rotating blade (moving component). The rail member and flow diverting member work together to control fluid flow at the source, achieving effective clearance reduction without the complexity of casing modifications.
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
The solution effectively reduces tip clearance flow, enhancing turbine stage efficiency and power generation while minimizing the risk of component interference by creating a vortex flow that reduces the effective clearance gap, thereby minimizing energy loss.
Implementation Method 1
The rail member diverts the fluid path in the first chamber into a generally curved configuration
Implementation Method 2
the second chamber directs the fluid path into a vortex configuration
Implementation Method 3
Any reduction in the amount of tip clearance flow can result in a direct gain in power and performance of the turbine stage
Data Source
AI summary
A flow control assembly is provided, including a member and a wall. The member has a surface, a flow diverting member and a rail member. The rail member is situated upstream of the flow diverting member. The flow diverting member and the rail member each project from the surface of the member. The flow diverting member has a distal end. The wall is disposed in relation to the member to create a clearance gap between the distal end of the flow diverting member and the wall. A fluid path is created between the member and the wall, and flows from an upstream section and through the clearance gap. A first chamber and a second chamber are defined by the wall and located upstream of the clearance gap.