Gas Turbine Inlet Lip Boundary Layer Control
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Solution Overview
Problem
Aircraft gas turbine engines face performance variations during diverse flight conditions, and existing inlet lip section designs that prevent airflow separation are often heavy and inefficient due to thick designs required for cross-wind and take-off conditions.
Innovation Solution
A gas turbine engine system with a bleed passage that introduces a controlled bleed airflow near the inlet lip section's boundary layer to simulate a thick inlet lip section, reducing the need for a thick design during specific flight conditions, thereby allowing a thinner, lighter nacelle assembly with improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inlet lip section is designed thick to prevent airflow separation during cross-wind and take-off conditions, then the engine operability is improved, but the nacelle weight and fuel burn increase
Solution Approach 1:
The invention applies dynamics by making the inlet lip section adjustable rather than fixed. A movable inlet lip section can be positioned in different configurations based on flight conditions - thicker effective profile during cross-wind and take-off, thinner during cruise. This dynamic adjustment resolves the contradiction by allowing the structure to optimize between reliability and weight depending on operational requirements.
Solution Approach 2:
The invention changes the geometric parameter of the inlet lip section by using variable geometry design. The lip section can alter its effective thickness parameter through movable components or adjustable positioning, transitioning between a thick profile for high reliability during critical phases and a thin profile for weight reduction during cruise operations.
2Reliability
If the inlet lip section is designed thick to prevent airflow separation, then the engine operability is improved, but the nacelle diameter increases
Solution Approach 1:
The movable inlet lip section enables the nacelle diameter to be dynamically adjusted. During cruise, the lip section can be positioned to minimize the effective diameter, reducing the aircraft's maximum diameter envelope. During cross-wind conditions, it can be repositioned to provide the necessary thickness for operability, thus resolving the contradiction between reliability and dimensional constraints.
Solution Approach 2:
The invention changes the geometric parameter of the inlet lip section by using variable geometry design. The lip section can alter its effective thickness parameter through movable components or adjustable positioning, transitioning between a thick profile for high reliability during critical phases and a thin profile for weight reduction during cruise operations.
3Ease of operation
If a thick inlet lip section is used to ensure engine operation during diverse conditions, then the ease of operation is improved, but the manufacturing complexity and weight increase
Solution Approach 1:
The movable inlet lip section applies dynamics by making the configuration adjustable rather than fixed. The system can transition between different operational states - providing a thick effective profile for cross-wind and take-off operations, and a thin profile for cruise. This dynamic capability enhances ease of operation across diverse conditions while managing complexity through controlled adjustability rather than always-being-thick design.
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 approach enhances engine performance by maintaining efficient airflow during various flight conditions while reducing the nacelle's weight and fuel burn, achieving a reduced maximum diameter and increased efficiency.
Implementation Method 1
The controller identifies an operability condition and selectively introduces the bleed airflow near a boundary layer of the inlet lip section in response to the operability condition
Data Source
AI summary
A gas turbine engine system for an aircraft includes a nacelle having a fan cowl with an inlet lip section and a core cowl, at least one compressor and at least one turbine, at least one combustor between the compressor and the turbine, a bleed passage, and a controller. The bleed passage includes an inlet for receiving a bleed airflow and an outlet that discharges the bleed airflow in an upstream direction from the outlet. The controller identifies an operability condition and selectively introduces the bleed airflow near a boundary layer of the inlet lip section in response to the operability condition.