Turbine Fan Case Bleed Air Cooling System
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Solution Overview
Problem
Gas turbine engines face challenges in utilizing bleed air as a cooling source due to limited space within bypass ducts, which hinders the incorporation of features that can effectively leverage this cooling potential.
Innovation Solution
The fan case assembly incorporates a bleed air flow control system that includes an air recirculation duct and a heat exchanger duct, allowing for selective bleeding of air to be used as a cooling source. This system directs a portion of the air through a heat exchanger before re-introducing it into the gas path, providing cooling while optimizing stall margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If bleed air is used as a cooling source within bypass ducts, then cooling efficiency is improved, but the limited space within bypass ducts prevents effective incorporation of cooling features
Solution Approach 1:
The patent moves the cooling system from the bypass duct space to the fan case assembly space. By locating the bleed air flow control system, heat exchanger, and air recirculation duct within the fan case assembly rather than within the bypass ducts, the invention utilizes a different spatial dimension (the fan case volume) to accommodate the cooling features, thereby resolving the space constraint while maintaining cooling functionality
Solution Approach 2:
The patent introduces an air recirculation duct as an intermediary component that connects the heat exchanger outlet back to the gas path. This recirculation mechanism allows the cooled air to be reintroduced into the flow, creating a closed-loop cooling system that efficiently utilizes the available space within the fan case assembly while achieving effective cooling
2Temperature
If a heat exchanger is incorporated into the fan case assembly, then cooling capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the cooling system components (bleed air flow control system, heat exchanger, air recirculation duct) into a single integrated fan case assembly. By combining these functions into one unified structure rather than distributing them separately, the invention reduces overall system complexity while maintaining full cooling capability
Solution Approach 2:
The fan case assembly is designed to serve multiple functions: it houses the bleed air flow control system, contains the heat exchanger, provides the air recirculation pathway, and maintains the gas path. This multi-functional design consolidates what would otherwise be separate systems into a single universal component, thereby improving cooling capability without proportionally increasing complexity
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 bleed air flow control system effectively utilizes bleed air as a cooling source within the fan case assembly, enhancing cooling efficiency and improving stall margin without occupying additional space within the bypass ducts.
Implementation Method 1
a heat exchanger in fluid communication with the cooling fluid passage. The cooling fluid passage may be configured to conduct the portion of the air through the heat exchanger to transmit heat from the heat exchanger to the portion of the air
Data Source
AI summary
A fan case assembly adapted for use with a gas turbine engine includes a fan casing and a bleed air flow control system. The fan casing includes an annular case and a fan track liner coupled with the annular case. The bleed air flow control system is configured to bleed selectively a portion of air flowing through a gas path of the fan case assembly for use as a cooling source in the fan case assembly.