Pivoting Impeller Shroud Clearance Control for Gas Turbine Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas turbine engines face inefficiencies due to air leakage through the clearance gap between the impeller and the impeller shroud, which is difficult to control effectively with conventional systems.
Innovation Solution
A clearance control system for the impeller shroud assembly that includes a unitary structure with a pivot point, cams, a sync ring, and hydraulic or magnetic actuators to precisely adjust the axial position of the impeller shroud, minimizing the clearance gap and matching the impeller's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clearance gap between impeller and impeller shroud is increased to prevent contact, then reliability is improved, but air leakage increases and compressor efficiency deteriorates
Solution Approach 1:
The impeller shroud is made dynamically adjustable through a clearance control device that can change the axial position of the shroud exducer portion. This allows the clearance gap to be optimized for different operating conditions, preventing contact when needed while minimizing leakage during efficient operation. The dynamic adjustment mechanism includes actuators that respond to control signals to modify shroud position in real-time.
Solution Approach 2:
The system changes the physical parameter of clearance gap magnitude by adjusting the axial position of the impeller shroud exducer portion. The clearance control device modifies the spatial parameter (clearance distance) based on operating conditions, allowing optimal balance between preventing contact and minimizing air leakage. This parameter adjustment is achieved through actuated movement of the shroud assembly.
2Loss of energy
If the clearance gap is minimized to improve compressor efficiency, then energy loss is reduced, but the risk of impeller contact with the shroud increases
Solution Approach 1:
The clearance control device enables dynamic adjustment of the impeller shroud axial position to maintain optimal clearance gap under varying operating conditions. This dynamic control allows the system to minimize clearance for efficiency while preventing contact through real-time position modification based on operational requirements.
Solution Approach 2:
The control system receives input signals that reflect impeller position and operating conditions, processes this information, and generates control signals to adjust the impeller shroud position accordingly. This feedback mechanism ensures the clearance gap is optimized to prevent contact while minimizing air leakage, adapting to changing conditions automatically.
3Manufacturing precision
If a complex clearance control system is implemented to precisely control the clearance gap, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The clearance control device is segmented into modular functional components: actuators for position adjustment, a sync ring for coordinated movement, and a control system for signal processing. This segmentation allows precise control of the clearance gap while managing complexity through modular design, where each component has a specific function and can be independently optimized or replaced.
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 system effectively minimizes air leakage by dynamically adjusting the clearance gap to match the impeller's displacement, enhancing compressor efficiency and reducing operational complexity.
Implementation Method 1
The at least one first magnet member may be an electromagnet
Implementation Method 2
The clearance control device may include at least one first magnet member. The axially-extending member may include at least one second magnet member mounted thereto
Implementation Method 3
The clearance control device may include a hydraulic pressure source and an actuator body defining an annular channel in fluid communication with the axially-extending member
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An impeller shroud assembly (54) for a gas turbine engine (20) includes an annular impeller shroud (40) disposed about an axial centerline (30). The impeller shroud (40) includes a shroud inducer portion (56) and a shroud exducer portion (58) disposed radially outward of the shroud inducer portion (56) and extending to an outer radial end (60) of the impeller shroud (40). The shroud inducer portion (56) and the shroud exducer portion (58) defining an impeller-facing surface (62) of the impeller shroud (40). The impeller shroud (40) has a pivot point (66) defined between the shroud inducer portion (56) and the shroud exducer portion (58). The impeller shroud assembly (54) further includes a clearance control device (72) connected to the shroud exducer portion (58) of the impeller shroud (40) proximate the outer radial end (60). The clearance control device (72) is configured to pivot the shroud exducer portion (58) of the impeller shroud (40) about the pivot point (66) between a first axial position and a second axial position.