Variable Bleed Cooling Passage for Gas Turbine Work Loss Reduction
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Solution Overview
Problem
Existing gas turbine engines face inefficiencies due to bleeding high-pressure, high-temperature air for cooling, which results in lost work and reduced efficiency.
Innovation Solution
A gas turbine engine design incorporating a cooling passage with a heat exchanger and a variable bleed assembly that utilizes low-pressure airflow for cooling, allowing efficient cooling of accessory systems while minimizing work loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high-pressure air is bled from compressors for cooling, then cooling capability is improved, but work loss and temperature increase occur
Solution Approach 1:
A heat exchanger is introduced as an intermediary device between the compressed air source and the components requiring cooling. The heat exchanger transfers thermal energy from the compressed air to the components, allowing cooling without direct contact and minimizing energy loss by recovering thermal energy that would otherwise be wasted.
Solution Approach 2:
The system changes the parameters of the air flow by using a heat exchanger to transfer heat at controlled rates. By managing the thermal energy transfer parameters rather than simply bleeding high-pressure air directly, the system achieves effective cooling while minimizing work loss and temperature increases in the compressed air.
2Temperature
If traditional cooling systems are used, then thermal management is achieved, but aerodynamic performance deteriorates
Solution Approach 1:
The cooling function is extracted from the main aerodynamic flow path by using a separate heat exchanger system. This allows thermal management to be achieved without interfering with the aerodynamic performance of the engine, as the cooling process occurs in a separate, non-intrusive manner that does not disrupt airflow over the engine surfaces.
3Temperature
If engine components are cooled effectively, then thermal management is improved, but engine length increases
Solution Approach 1:
The heat exchanger is nested within or integrated with existing engine structures, allowing the cooling system to be accommodated within the engine's overall footprint. This nesting approach enables effective thermal management while minimizing the increase in engine length, as the cooling components are incorporated into the existing engine architecture rather than adding external length.
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 design achieves efficient cooling of accessory systems with reduced energy loss, enhancing overall engine efficiency and propulsive performance.
Implementation Method 1
A heat exchanger is provided in thermal communication with an airflow through the cooling passage
Data Source
AI summary
A gas turbine engine is provided. The gas turbine engine includes: a fan; a turbomachine drivingly coupled to the fan and defining in part a working gas flowpath, the gas turbine engine defining a bypass passage over the turbomachine, the turbomachine defining an annular cooling passage extending between a CP inlet and a CP outlet, the CP inlet in airflow communication with the working gas flowpath and the CP outlet in airflow communication with the bypass passage; and a variable bleed assembly including a variable bleed duct extending between a VB inlet and a VB outlet, the VB inlet in airflow communication with the working gas flowpath at a location downstream of the CP inlet and the VB outlet in airflow communication with the annular cooling passage for urging an airflow through the cooling passage.