Low Profile Triaxial Blade Tip Clearance Probe Assembly
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Solution Overview
Problem
Traditional fan and turbine blade tip clearance (BTC) sensors alter engine structures, reducing gas turbine efficiency by disrupting the air seal and requiring modifications that compromise performance.
Innovation Solution
A low-profile triaxial BTC probe design with a housing, insulators, and a sensor element that minimizes structural disruption by using a specific configuration of cavities, necks, and compressive forces to maintain the air seal integrity while monitoring blade tip clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional cap probes are installed to monitor blade tip clearance, then measurement capability is provided, but engine structure is altered and air seal integrity is compromised
Solution Approach 1:
The probe assembly employs a nested structure where the inner housing is disposed within the outer housing, the sensor element is received within the inner housing, and multiple insulators are nested within cavities. This nested configuration allows the complete probe assembly to fit within a compact footprint, minimizing the space required and reducing disruption to the air seal while maintaining full measurement capability
Solution Approach 2:
The probe assembly transitions from traditional extended configurations to a low-profile three-dimensional arrangement. By utilizing vertical stacking (inner housing within outer housing) and radial nesting (sensor elements positioned within multiple cavities), the design achieves precise blade tip clearance measurement capability while reducing the probe's axial and radial footprint to minimize air seal disruption
2Measurement precision
If traditional cap probes are installed to monitor blade tip clearance, then measurement capability is provided, but engine efficiency is reduced
Solution Approach 1:
The nested configuration of housings, sensor elements, and insulators creates a compact probe assembly that minimizes interference with engine airflow and maintains air seal integrity. This reduces energy loss while providing accurate blade tip clearance measurements for efficiency optimization
Solution Approach 2:
The probe assembly uses localized insulating materials (outer hat insulator, inner hat insulator, outer cap insulator, inner cap insulator) positioned at specific locations to provide electrical isolation only where needed. This localized approach maintains air seal integrity in critical areas while providing measurement capability, rather than using extensive shielding that would disrupt airflow and reduce engine efficiency
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 low-profile triaxial BTC probe effectively monitors blade tip clearance without altering engine structures, thereby maintaining or improving gas turbine efficiency by ensuring precise measurements without compromising the air seal.
Implementation Method 1
a capacitance-based BTC probe (cap probe) may be placed proximate the outer air seal to monitor this gap
Data Source
AI summary
A low profile triaxial BTC probe may comprise a housing having a first body, a first cavity within the first body, and a neck extending radially from the first body, an outer hat insulator disposed within the first cavity, an inner housing, disposed within the first cavity, having a second body and a second cavity within the second body, an inner hat insulator disposed within the second cavity, a sensor element disposed within the second cavity, an inner cap insulator disposed within the second cavity, an inner cap over the inner cap insulator, an outer cap insulator disposed within the first cavity, a cap over the outer cap insulator, and a hard lead comprising a hard shield, a driven guard, and a lead wire.