Fan Casing Cooler with Shape-Memory Actuation for Drag Reduction
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Solution Overview
Problem
Current surface coolers for aircraft engines are statically oversized during off-peak conditions, leading to increased aerodynamic drag and specific fuel consumption, as they are designed for maximum engine load, necessitating a solution to adaptively balance cooling performance with drag reduction.
Innovation Solution
A fan casing cooler with a thermally sensitive portion made of metal layers that change shape in response to temperature changes, passively positioning the cooler to optimize energy transfer during peak demand while minimizing drag during off-peak conditions, using materials like aluminum alloy and aluminum silicon carbide, and incorporating shape-memory alloys for actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cooler is designed with large fin geometry and height for maximum engine load, then cooling performance is improved, but aerodynamic drag increases during off-peak conditions
Solution Approach 1:
The cooler incorporates a passive retraction and extension system that allows the fin geometry to dynamically adjust its position relative to the airflow. During peak demand, the cooler extends into the airflow path to maximize cooling; during off-peak conditions, it retracts to minimize aerodynamic drag, thereby resolving the contradiction between cooling performance and drag reduction.
Solution Approach 2:
The system changes the geometric parameters of the cooler (specifically the fin exposure to airflow) based on thermal conditions. By varying the cooler's effective surface area and orientation in response to temperature demands, the system optimizes both cooling efficiency and aerodynamic performance across different operating conditions.
2Power
If the cooler is statically positioned for maximum cooling capacity, then heat transfer efficiency is improved, but specific fuel consumption increases due to excess drag
Solution Approach 1:
The passive retraction and extension system enables the cooler to dynamically adjust its configuration based on thermal demand. This eliminates the need for a static oversized design, allowing the cooler to maintain high heat transfer efficiency when needed while minimizing energy loss to drag during low-demand operations, thereby reducing specific fuel consumption.
Solution Approach 2:
The cooler's retraction and extension system operates passively, utilizing the thermal conditions and airflow itself to drive the adjustment mechanism without requiring external energy input. This self-regulating system automatically optimizes the balance between cooling performance and fuel efficiency based on real-time operating conditions.
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 solution effectively balances cooling performance with reduced aerodynamic drag, improving specific fuel consumption by passively adjusting the cooler's position and geometry in response to thermal conditions, enhancing efficiency during both peak and off-peak engine operations.
Implementation Method 1
the body includes at least one thermally sensitive portion configured to changes shape in response to a change in a thermal condition
Implementation Method 2
Heat exchangers can be placed in a turbine jet engine fan case, using bypass air to remove lube oil energy through forced convection
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
An apparatus and method for cooling a fluid within a turbine engine (10). A fan casing assembly (18) for the turbine engine (10) can include an annular fan casing (38) with a peripheral wall (43) having a flow path (14) defined through the casing (38). A fan casing cooler (50) includes a body (70) to confront the peripheral wall (43) with at least one conduit (74) configured to carry a flow of heated fluid to convectively cool the heated fluid with a flow of air (72) through the flow path (14).