Precooler Inside Intermediate Chamber Reduces Drag
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Solution Overview
Problem
Existing bypass turbine engines experience aerodynamic disturbances and increased drag due to the placement of precoolers in the fan duct, which also result in inefficient heat exchange and temperature regulation of the hot air used for aircraft functions.
Innovation Solution
The precooler is positioned inside the intermediate chamber in thermal contact with the rear part of the inner fairing, utilizing both external cold stream airflow and internal cooling air to cool hot air, with a controllable air intake and annular cross-section design for enhanced heat exchange, and optionally a double-walled inner fairing with curved ducts for improved cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the precooler is housed in the fan duct, then the hot air can be cooled by the cold stream, but aerodynamic disturbances are generated in the cold stream and drag increases
Solution Approach 1:
The precooler is extracted from the fan duct and relocated to the intermediate chamber surrounding the central generator. This separation removes the source of aerodynamic disturbances from the cold stream path while preserving the cooling function through thermal contact with the inner fairing and access to cold air via dedicated intakes.
Solution Approach 2:
The inner fairing acts as an intermediary thermal medium. The precooler maintains thermal contact with the rear part of the inner fairing, which is itself cooled by the cold stream in the fan duct. This indirect cooling path allows heat exchange without direct placement in the cold stream, eliminating aerodynamic disturbances.
2Temperature
If cold air is bled from the cold stream to cool the hot stream, then heat exchange occurs, but the heated cold air must be discharged outside increasing drag
Solution Approach 1:
The cooling function is merged with the existing cold stream flow path. Instead of creating a separate discharge path for heated air, the system utilizes the cold stream that already flows through the fan duct. The precooler is positioned to be cooled by this existing flow, and the heated air is discharged through the rear orifice along with the cold stream, eliminating additional drag from separate discharge.
Solution Approach 2:
The cold stream serves dual purposes: it cools the precooler indirectly through the inner fairing and provides the cooling medium for the precooler's air intake. The system uses its own cold stream resource to achieve cooling without requiring external cooling resources or creating additional harmful discharges.
3Object-affected harmful factors
If the precooler is positioned inside the intermediate chamber with thermal contact to the inner fairing, then aerodynamic disturbances in the fan duct are avoided, but the heat exchange path becomes indirect
Solution Approach 1:
The inner fairing serves as a thermal intermediary between the cold stream and the precooler. The precooler is thermally coupled to the rear part of the inner fairing, which is directly exposed to the cold stream. This indirect thermal path through the fairing wall effectively transfers heat while maintaining clean airflow in the fan duct.
Solution Approach 2:
The cooling system is segmented into distinct functional zones: the cold stream flow path in the fan duct, the thermal transfer interface through the inner fairing wall, and the precooler in the intermediate chamber. This segmentation allows each component to perform its function optimally without interfering with others, particularly protecting the cold stream from aerodynamic disturbances.
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 configuration minimizes aerodynamic disturbances, reduces drag, and allows for precise temperature control of the cooled hot air by using external and internal cooling sources effectively, improving the overall efficiency of the turbine engine.
Implementation Method 1
a precooler comprising an inlet for a current of hot air bled from said central generator and an outlet for a current of cooled hot air generated using said cold stream
Implementation Method 2
said precooler is positioned inside said intermediate chamber in thermal contact with the rear part of the inner fairing
Implementation Method 3
utilizing both external cold stream airflow and internal cooling air to cool hot air
Data Source
AI summary
A pre-cooler having an annular cross-sectional shape about the axis of a pod and arranged inside the rear part of an inner shroud in external contact with a cold flow exiting a fan duct channel and in close contact with a cooling air stream drawn from the cold flow.