Intercooled Cooling Air System for Gas Turbine High Pressure Turbine
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gas turbine engines face challenges in providing effective cooling to high-pressure turbine sections due to the limitations of existing heat exchanger technology, which struggles with high temperatures and pressures, especially as temperatures at the downstream most location of the high pressure compressor approach 732.2°C (1350°F).
Innovation Solution
The proposed solution involves tapping air from an upstream portion of the compressor section and passing it through a heat exchanger positioned in the bypass duct, where it is cooled by bypass air, and then mixing it with air from a downstream location before delivering it to the high pressure turbine section, utilizing a centrifugal compressor impeller driven by a bull gear with a gear ratio multiplier to optimize speed and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is tapped from the downstream most end of the high pressure compressor, then the air temperature is high enough to provide effective cooling, but the existing heat exchanger technology cannot handle the high temperatures and pressures
Solution Approach 1:
The cooling air supply system is segmented into multiple sources: cold air from an upstream compressor location and hot air from the downstream most end of the high pressure compressor. This segmentation allows each air source to serve a specific purpose - the cold air protects the heat exchanger from high temperatures while the hot air provides the necessary cooling temperature when mixed with the turbine section.
Solution Approach 2:
Cold air from an upstream compressor location acts as an intermediary substance that protects the heat exchanger from direct exposure to high temperatures and pressures. This intermediary air is mixed with the hot cooling air after heat exchange, allowing the heat exchanger to operate within safe temperature limits while still achieving effective cooling of the turbine section.
2Stress or pressure
If air is compressed to high pressure for delivery to the turbine section, then the cooling effectiveness is improved, but the energy required to compress the air increases
Solution Approach 1:
Air is compressed to the required high pressure in advance at an upstream location in the compressor section, before it is needed for cooling the turbine section. This preliminary compression allows the air to be delivered to the turbine at the necessary pressure without requiring additional compression energy at the point of use.
Solution Approach 2:
The compressor section serves dual purposes: it both compresses air for combustion and provides compressed cooling air to the turbine section. The compression process inherently provides the high-pressure cooling air needed, eliminating the need for separate compression systems and reducing overall energy requirements.
3Temperature
If air is cooled by passing it through a heat exchanger, then the cooling efficiency is improved, but the heat exchanger materials must withstand high temperatures which limits existing technology
Solution Approach 1:
Cold air from an upstream compressor location serves as a protective intermediary that allows the heat exchanger to operate at lower temperatures. This intermediary air is mixed with the hot cooling air after the heat exchange process, enabling the heat exchanger to achieve effective cooling without being exposed to the high temperatures that would require specialized materials.
Solution Approach 2:
The temperature parameters of the cooling air are changed in two stages: first, cold air is introduced to reduce the temperature of the air stream passing through the heat exchanger; second, hot air from the downstream compressor is mixed in after heat exchange to restore the necessary cooling temperature. This parameter change approach allows the heat exchanger to operate within material limits while still achieving effective cooling.
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 approach reduces the energy required to compress the air, allowing it to be delivered at a lower temperature and higher pressure, enhancing cooling efficiency and reducing energy losses, while also allowing for the use of existing heat exchanger materials, thus overcoming the limitations of current technology.
Implementation Method 1
passed through a heat exchanger positioned in the bypass duct, where it is cooled by bypass air
Implementation Method 2
utilizing a centrifugal compressor impeller driven by a bull gear with a gear ratio multiplier to optimize speed and efficiency
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A gas turbine engine comprises a main compressor section having a high pressure compressor with a downstream discharge, and more upstream locations. A turbine section has a high pressure turbine (117). A tap (110) taps air from at least one of the more upstream locations in the compressor section, passes the tapped air through a heat exchanger (112) and then to a cooling compressor. The cooling compressor compresses air downstream of the heat exchanger (112), and delivers air into the high pressure turbine (117). The cooling compressor includes a downstream connection that delivers discharge pressure air to an upstream location in the high pressure turbine and a second tap (160) from an intermediate pressure location within the cooling compressor. The second tap (160) is connected to a downstream location within the high pressure turbine (117). An intercooling system for a gas turbine engine is also disclosed.