Turbomachine Casing Clearance Control via Segmented Radial Adjustment
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Solution Overview
Problem
Current clearance control systems for turbomachines, such as gas turbines, struggle to accurately and efficiently adjust running clearances under various operating conditions, particularly during transient states, due to limitations in responding to rapid changes and displacements caused by centrifugal, thermal, and maneuver loads, leading to inefficiencies and increased maintenance costs.
Innovation Solution
A clearance control system with each segment of the casing coupled to at least three adjusting devices, including adjusting gear units, actuators, and control rods, allowing for circular path curvature and independent adjustment of running clearance, regardless of operating state, to compensate for multiple influencing variables and ensure reliable and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a clearance control system uses a segmented casing with adjusting devices to maintain optimal running clearance, then the running clearance can be kept small and constant, but the device complexity increases due to multiple adjusting devices and actuators
Solution Approach 1:
The casing is divided into multiple segments that can be independently adjusted radially. Each segment is coupled to adjusting devices that can move it relative to the rotor, allowing precise control of running clearance in different regions of the turbomachine
Solution Approach 2:
The clearance control system uses actuators to dynamically adjust the position of casing segments in real-time based on operating conditions. The system transitions from a static casing to a dynamically adjustable one, maintaining optimal clearance during transient states and different operating phases
2Reliability
If the casing segments are adjusted radially to compensate for rotor expansion, then the running clearance can be maintained, but the system cannot compensate for displacements and ovalizations caused by maneuver loads
Solution Approach 1:
The adjusting devices are not limited to pure radial adjustment but can also accommodate axial and tangential movements. This multi-dimensional adjustment capability allows the system to compensate for various types of deformations including ovalizations and displacements caused by maneuver loads, not just thermal expansion
3Loss of energy
If the running clearance is reduced to improve efficiency, then fuel consumption decreases, but the risk of rotor blade contact with casing increases during transient operation
Solution Approach 1:
The clearance control system anticipates transient states and proactively adjusts casing segment positions before critical conditions occur. During acceleration or deceleration phases, the system pre-adjusts clearances to prevent both excessive gaps that waste energy and potentially harmful contacts, maintaining safety margins while optimizing efficiency
Solution Approach 2:
The system continuously monitors running clearance and operating conditions, using feedback signals to adjust casing segment positions in real-time. This closed-loop control ensures that clearance remains within safe and efficient ranges during all operating phases, preventing rotor blade contact while minimizing energy losses
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 enables precise and efficient adjustment of running clearance, reducing fuel consumption, lowering costs and weight, and enhancing reliability and maintainability, while preventing sickle-shaped clearances and accommodating thermal and mechanical deformations.
Implementation Method 1
The adjusting devices (20) are designed to transform an at least predominantly axial movement of the adjusting element (22) into an at least predominantly radial movement of the respectively associated segments (16a-d) of the casing (18)
Implementation Method 2
the radius of the rotor or of the rotor disk in the region B1—proportional to the change in rpm—experiences a change in radius due to the acting centrifugal forces
Implementation Method 3
the running clearance can vary relatively strongly on account of the differing temporal expansion behaviors of the rotor and its casing
Data Source
AI summary
The invention relates to a clearance control system for adjusting a running clearance (L) between a rotor (12) having rotor blades (10) of a turbomachine (14), especially a gas turbine, and a casing (18) that surrounds at least sections thereof and comprises at least two segments (16a-d), the clearance control system having at least one adjusting device (20), which can be coupled to at least one segment (16a-d) of the casing (18), and by means of which the at least one segment (16a-d) can be moved radially in relation to a rotational axis (D) of the rotor (12) for adjusting the running clearance (L), wherein each segment (16a-d) of the casing (18) is coupled to at least three adjusting devices (20) of the clearance control system. The invention also relates to a turbomachine (14), especially a gas turbine, as well as to a method for adjusting a running clearance (L).