Bypass Duct Fluid Cooler Layout for Low-Loss Turbofan Cooling
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Solution Overview
Problem
Installing a heat exchanger in the bypass duct of a turbofan gas turbine engine disrupts the flow of bypass air, leading to energy losses and increased specific fuel consumption.
Innovation Solution
A fluid cooler system is designed with an inlet duct protruding into the bypass duct, a heat exchanger oriented obliquely to the bypass air flow, and an outlet duct to return cooled air, minimizing disruption and allowing for efficient heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat exchanger is installed inside the bypass duct, then heat transfer between bypass air and other systems is enabled, but the flow of bypass air is disrupted causing energy losses and increased specific fuel consumption
Solution Approach 1:
The heat exchanger is repositioned from an in-duct installation to an external installation on the bypass duct. This spatial relocation allows bypass air to flow along the external heat exchanger surface without significant flow disruption, while still enabling effective heat transfer. The three-dimensional arrangement of inlet/outlet ducts and heat exchanger components optimizes airflow patterns and reduces energy losses.
Solution Approach 2:
The heat exchanger system is divided into multiple functional components: inlet duct for capturing bypass air, external heat exchanger unit for heat transfer, and outlet duct for returning cooled air. This segmentation allows each component to be optimized independently for its specific function while maintaining overall system efficiency and minimizing interference with bypass airflow.
2Temperature
If a heat exchanger is installed inside the bypass duct, then cooling function is provided, but specific fuel consumption increases
Solution Approach 1:
By moving the heat exchanger externally and configuring the inlet/outlet ducts to capture and return bypass air efficiently, the system maintains cooling functionality while minimizing interference with the main bypass airflow. This reduces the energy penalty and lowers specific fuel consumption compared to internal installation.
3Temperature
If a heat exchanger is installed in the bypass duct, then heat transfer is facilitated, but flow disruption occurs
Solution Approach 1:
The heat exchanger is positioned externally on the bypass duct with inlet and outlet ducts that capture bypass air and return it after heat transfer. This external configuration allows bypass air to flow smoothly along the heat exchanger surface without the blockage and turbulence caused by internal installation, thereby maintaining high flow efficiency while enabling effective heat transfer.
Solution Approach 2:
The inlet and outlet ducts are designed with curved trajectories to smoothly guide bypass air into and out of the heat exchanger. This curved geometry minimizes flow separation and turbulence, maintaining streamlined airflow and reducing energy losses associated with abrupt directional changes.
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 reduces energy losses and maintains engine performance by optimizing airflow through the heat exchanger, providing a net thrust benefit under certain conditions.
Implementation Method 1
a heat exchanger in fluid communication with the inlet duct, the heat exchanger facilitating heat transfer between a fluid and the portion of bypass air received into the inlet duct
Data Source
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AI summary
A fluid cooler (24) for installation in a bypass duct (22) of a turbofan gas turbine engine and associated methods are provided. The fluid cooler (24) includes an inlet duct (62), a heat exchanger (40) and an outlet duct (64). The inlet duct (62) includes an inlet (32) protruding into the bypass duct (22) to receive a portion of the bypass air (b) into the inlet duct (62). The heat exchanger (40) is in fluid communication with the inlet duct (62). The heat exchanger (40) facilitates heat transfer between a fluid (F) and the portion of bypass air (b) received into the inlet duct (62). The heat exchanger (40) defines a general flow direction for the portion of bypass air (b) that is different from the main flow direction (D1) of bypass air (B) inside the bypass duct (22). The outlet duct (64) conveys the portion of bypass air (b) from the heat exchanger (40) back to the bypass duct (40).