Load Compressor Cooling for APU Gas Generator Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current auxiliary power unit (APU) systems face challenges in achieving efficient cooling and power generation due to high operating temperatures, particularly in cooling the hot section components like the combustor and turbine, which can lead to reduced efficiency and component lifespan.
Innovation Solution
The implementation of a load compressor driven by a turbine, which compresses air and directs a portion of it as cooling air to the gas generator section, including the combustor and air bearings, thereby reducing temperature and improving efficiency by eliminating the need for core compressor airflow for cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high operating temperature is used in the gas generator section, then power generation efficiency is improved, but component lifespan is reduced due to thermal stress
Solution Approach 1:
The patent divides the air flow system into two separate compressors: a core compressor for power generation and a load compressor for cooling. This segmentation allows independent optimization of each function, enabling high temperature operation for power generation while dedicating separate resources for cooling and protection.
Solution Approach 2:
The load compressor acts as an intermediary device that provides cooling air to the gas generator section components. This intermediary system protects the hot section components from excessive thermal stress by introducing cooler air, thereby extending component lifespan without reducing power generation efficiency.
2Temperature
If core compressor airflow is used for cooling, then cooling effectiveness is improved, but power generation efficiency is reduced due to reduced airflow for combustion
Solution Approach 1:
The patent segments the compression function into two independent systems: the core compressor dedicated to providing air for combustion and power generation, and the load compressor dedicated to providing cooling air. This eliminates the trade-off by ensuring that cooling airflow does not compromise the airflow available for combustion and power generation.
Solution Approach 2:
The load compressor is driven by power extracted from the turbine, making the cooling system self-sufficient and independent of the core compressor output. This self-service cooling system allows the core compressor to operate at full capacity for power generation without diverting airflow for cooling purposes.
3Reliability
If additional cooling systems are added to cool the gas generator section, then component protection is improved, but device complexity increases
Solution Approach 1:
The load compressor serves multiple functions: it provides cooling air to the gas generator section, drives the inlet guide vane mechanism through a shaft connection, and can potentially supply air for other aircraft systems. This multi-functionality reduces overall system complexity by consolidating multiple functions into a single component.
Solution Approach 2:
The patent combines the cooling system with the existing APU architecture by integrating the load compressor into the gas generator section and coupling it with the turbine through a shared shaft system. This merging approach leverages existing structural and mechanical systems rather than adding completely separate cooling infrastructure.
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 solution enhances the cooling efficiency of APU systems, extends component life, and improves power generation by reducing the power required for cooling, allowing the load compressor to draw more power from the gas generator section without sacrificing other operational uses.
Implementation Method 1
The core compressor is configured to receive and compress a first flow of air to a first high pressure
Implementation Method 2
The combustion assembly is configured to receive the first compressed air from the core compressor, mix the first compressed air with fuel, and combust the first compressed air and fuel mixture to result in combustion gases
Implementation Method 3
The turbine is configured to extract power from the combustion gases and drive the core compressor and the load compressor
Implementation Method 4
The load compressor is configured to receive and compress a second flow of air to a second high pressure to provide a second compressed cooling air flow to the gas generator section
Implementation Method 5
At least a portion of the second compressed air is directed to the gas generator section as cooling air
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An engine system includes a gas generator section and a load compressor. The gas generator section includes a core compressor, a combustion assembly, and a turbine. The core compressor receives and compresses a first flow of air as first compressed air. The combustion assembly receives the first compressed air from the compressor, mixes the first compressed air with fuel, and combusts the first compressed air and fuel mixture to result in combustion gases. The turbine receives the combustion gases from the combustion assembly and extracts energy from the combustion gases. The load compressor is driven by the turbine, and it is further configured to receive and compress a second flow of air as second compressed air. At least a portion of the second compressed air is directed to the gas generator section as cooling air.