Blade Tip Clearance Sensor Mounting for Heat and Vibration Stability
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Solution Overview
Problem
Existing blade tip clearance sensors in gas turbines face challenges in maintaining stable operation and response reliability under harsh environments such as high temperature, high pressure, and high vibration, due to instability in probe fixation.
Innovation Solution
A blade tip clearance sensor design featuring a bushing portion, washer portion, flange portion, sensor probe, spacer, and locking screw, secured with a high-strength and high-temperature resistant material, allowing for stable fixation and cooling of the sensor probe, ensuring reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor probe is fixed using conventional methods, then the device complexity is reduced, but the reliability of the sensor under harsh operating conditions deteriorates
Solution Approach 1:
The fixation structure is divided into multiple functional segments: bushing portion for positioning, washer portion for support, flange portion for mounting, spacer for spacing, and locking screw for securing. Each segment performs a specific function, collectively ensuring stable sensor fixation under harsh conditions while maintaining reasonable overall complexity.
Solution Approach 2:
The bushing portion acts as an intermediary component between the sensor probe and the turbine casing. It provides a stable mounting interface that isolates the sensor probe from direct exposure to harsh operating conditions while ensuring precise positioning and secure fixation.
2Measurement precision
If the sensor probe is exposed to harsh environments for monitoring, then the measurement capability is improved, but the durability of the sensor deteriorates
Solution Approach 1:
The bushing portion and flange portion provide protective cushioning for the sensor probe before it is exposed to harsh environments. These components shield the sensor from direct thermal and mechanical stress, extending its service life while maintaining measurement capability in the blade tip clearance monitoring application.
Solution Approach 2:
The bushing portion serves as a protective intermediary between the sensor probe and the harsh operating environment. It allows the sensor to maintain precise measurements of blade tip clearance while reducing direct exposure to high temperature and vibration, thereby extending sensor durability.
3Measurement precision
If the sensor probe is positioned close to the blade tip for accurate monitoring, then the measurement precision is improved, but the thermal stress on the sensor increases
Solution Approach 1:
The bushing portion and spacer act as thermal intermediaries between the sensor probe and the high-temperature blade tip environment. They enable the sensor to maintain accurate clearance measurements while reducing direct thermal coupling, thereby lowering the temperature exposure of the sensor components.
Solution Approach 2:
The fixation structure employs local quality differentiation where the bushing portion and flange portion are designed to withstand high thermal stress, while the sensor probe itself remains relatively protected. This localized structural differentiation allows precise measurement near the blade tip while managing thermal exposure through material and geometric design.
Data Source
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AI summary
Proposed are a blade tip clearance sensor and a gas turbine including the same. The blade tip clearance sensor includes a bushing portion which is fixed to a ring segment mounted on a turbine casing that accommodates a turbine blade therein and which has an internal space, a washer portion mounted on a lower portion of the internal space and provided with a first hollow portion, a flange portion provided on an upper surface of the washer portion and provided with a second hollow portion, a sensor probe which is inserted into the first and second hollow portions and which has a sensor cable, a spacer provided on an upper surface of the flange portion and configured to accommodate the sensor probe therein, and a locking screw which is provided on an upper surface of the spacer and which has a thread engaged with a thread of the bushing portion.