Piezoelectric Gas Injection Nozzle for Turbine Flutter Measurement
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Solution Overview
Problem
Existing systems for measuring aeromechanical damping characteristics of rotating equipment in gas turbine engines are inadequate for identifying flutter susceptibility, leading to potential component degradation and failure.
Innovation Solution
A gas injection nozzle system with a pintle and piezoelectric actuator, controlled by a controller, is used to induce controlled gas flow variations for precise measurement of damping characteristics, utilizing a flexure disk and pressure regulation to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing measurement systems are used, then the system structure is simple, but the measurement precision of aeromechanical damping characteristics is insufficient
Solution Approach 1:
The measurement system is divided into independent functional modules: gas injection subsystem (nozzle, pintle, piezoelectric actuator), measurement subsystem (sensors, data acquisition), and control subsystem. Each module operates independently but coordinates through standardized interfaces, enabling high-precision measurement while maintaining manageable system complexity through modular architecture.
2Quantity of substance
If gas flow control gap is increased, then the gas flow rate increases, but the control precision over flow rate decreases
Solution Approach 1:
The pintle is designed with dynamic positioning capability driven by a piezoelectric actuator, allowing real-time adjustment of the gas flow control gap. This dynamic control mechanism enables precise regulation of gas flow rate by varying the gap size in response to control signals, achieving both high flow rate and precise flow control through active feedback management.
Solution Approach 2:
The manual or mechanical flow control mechanism is replaced with a piezoelectric actuator that converts electrical signals directly into precise mechanical displacement of the pintle. This substitution enables high-precision control of the gas flow gap with minimal mechanical play or wear, achieving superior flow control precision compared to traditional mechanical adjustment systems.
3Measurement precision
If measurement frequency is increased, then the capability to detect high-frequency flutter is improved, but the system response time requirement increases
Solution Approach 1:
The system employs periodic gas injection through the controlled gap, creating oscillating flow patterns that excite and measure aeromechanical damping at specific frequencies. By adjusting the injection frequency, the system can target and measure high-frequency flutter conditions while maintaining manageable response time requirements through resonant excitation techniques.
Solution Approach 2:
The controlled gas flow through the adjustable gap serves as an intermediary mechanism that translates electrical control signals into aerodynamic excitation forces. This intermediary gas flow system enables indirect measurement of high-frequency vibrations by measuring the response to controlled gas injection, rather than requiring direct high-speed contact measurement that would demand extremely fast response times.
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 measures aeromechanical damping characteristics at high frequencies, enabling improved component design and operational criteria to prevent or minimize flutter, thereby enhancing the reliability of gas turbine engines.
Implementation Method 1
The piezoelectric actuator is coupled with the pintle. The piezoelectric actuator is configured to move the pintle between the first position and the second position.
Implementation Method 2
rotational equipment may experience vibrational instability (e.g., 'flutter') in response to aerodynamic forces experienced by the rotational equipment
Data Source
AI summary
A gas injection nozzle includes a nozzle housing, a pintle, and a piezoelectric actuator. The nozzle housing extends along an axis. The nozzle housing includes an inner wall, an outer wall, and an axial endwall. The inner wall and the outer wall form an outer cavity radially between the inner wall and the outer wall. The inner wall forms an inner cavity radially within the inner wall. The nozzle housing further forms a nozzle outlet passage through the axial endwall along the axis. The nozzle outlet passage is connected in fluid communication with the outer cavity by a gap at the first axial endwall. The pintle extends along the axis within the inner cavity and further forms the gap. The pintle is axially movable to vary a size of the gap. The piezoelectric actuator is coupled with the pintle and configured to move the pintle.