Dual-Pressure Turbine Cooling Air Tapping System
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Solution Overview
Problem
Gas turbine engine turbine sections face high temperatures, and existing cooling methods using hot downstream compressor air from the compressor section are inefficient, particularly at upstream rotor stages where high pressure compressed air is needed for effective cooling.
Innovation Solution
A dual-pressure air tapping system is implemented, where higher pressure air from a first location in the compressor passes through a heat exchanger to cool the first stage blade row, while lower pressure air from a downstream location cools the downstream blade row, with air paths strategically directed to optimize cooling efficiency across the turbine section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hot downstream compressor air is used to cool the turbine section, then cooling is provided, but cooling efficiency is insufficient particularly at upstream rotor stages
Solution Approach 1:
The turbine cooling system is segmented into multiple zones with different cooling air sources: upstream rotor stages are cooled by high-pressure air from an upstream compressor location, while downstream rotor stages are cooled by lower-pressure air from a downstream compressor location. This segmentation allows each zone to receive optimally pressurized cooling air matched to its specific cooling requirements.
Solution Approach 2:
Different qualities of cooling air (different pressures) are supplied to different locations within the turbine section. Upstream stages receive high-pressure cooling air for effective cooling, while downstream stages receive lower-pressure air. This local differentiation of cooling air quality optimizes cooling efficiency at each specific location.
2Reliability
If high pressure compressed air is used for cooling upstream rotor stages, then cooling efficiency improves, but system complexity increases due to multiple air taps and heat exchangers
Solution Approach 1:
Multiple compressor air taps serve dual purposes: they provide cooling air for specific turbine stages while also maintaining compressor pressure balance. The heat exchanger serves multiple functions by cooling both the cooling air and potentially recovering heat for other engine systems. This multi-functionality reduces overall system complexity despite the presence of multiple components.
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 cooling arrangement enhances the efficiency of the gas turbine engine by effectively managing temperature differences and extending turbine disk life, making efficient use of air delivered into the compressor section, especially in high-bypass ratio engines.
Implementation Method 1
The higher pressure tap passes through a heat exchanger, and then is delivered to cool the first stage blade row in the turbine section
Implementation Method 2
delivered to cool the first stage blade row in the turbine section
Implementation Method 3
passes through a heat exchanger, and then is delivered to cool the first stage blade row
Data Source
AI summary
A gas turbine engine comprises a compressor section and a turbine section, with the turbine section having a first stage blade row and a downstream blade row. A higher pressure tap is tapped from a higher pressure first location in the compressor. A lower pressure tap is tapped from a lower pressure location in the compressor which is at a lower pressure than the first location. The higher pressure tap passes through a heat exchanger, and then is delivered to cool the first stage blade row in the turbine section. The lower pressure tap is delivered to at least partially cool the downstream blade row.