Vortex Tube Cooling With Fluidic Oscillators for Gas Turbine Blades
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Solution Overview
Problem
Conventional impingement cooling systems in gas turbine blades utilize hot compressed air, leading to limited heat transfer rates and uneven temperature profiles, posing challenges in maintaining adequate cooling performance and thermal stress management.
Innovation Solution
A cooling system incorporating a vortex tube to separate compressed fluid into cold and hot streams, combined with a fluidic oscillator to generate biaxial pulsating jets at different frequencies, enhancing heat transfer efficiency and uniformity through orthogonal outlet passages and internal flow networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hot compressed air is used for impingement cooling, then the cooling system can operate with available compressor output, but the heat transfer rate is limited and cooling effectiveness is reduced
Solution Approach 1:
The compressed air flow is segmented into multiple oscillating jets that sweep across the blade surface, increasing the effective cooling area and improving heat transfer efficiency compared to a single steady jet
Solution Approach 2:
The fluidic oscillator generates periodic oscillating jets that move back and forth across the impingement surface, enhancing turbulence and heat transfer while using the same hot compressed air supply
2Temperature
If steady-state impinging jets are used, then the cooling system is simple to implement, but the surface temperature profile is uneven and thermal stresses increase
Solution Approach 1:
The fluidic oscillator creates periodic oscillating jets that sweep across the blade surface, distributing cooling more uniformly and reducing hot spots and thermal stresses
Solution Approach 2:
The cooling system transitions from steady-state to dynamic oscillating jets, allowing the cooling flow to adapt and cover larger surface areas while improving temperature uniformity
3Temperature
If the compressor discharge temperature is high, then the available cooling air is readily available, but the temperature differential between cooling air and blade surface is small
Solution Approach 1:
The oscillating jets enhance heat transfer coefficients through increased turbulence and surface coverage, compensating for the reduced temperature differential available from hot compressed air
Solution Approach 2:
The cooling flow is divided into multiple oscillating jets that increase the effective heat transfer area and improve overall cooling efficiency despite limited temperature differential
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 system achieves superior cooling performance by increasing the cooling surface area and reducing thermal stresses, extending the service life of gas turbine blades while allowing flexible installation and reducing maintenance costs.
Implementation Method 1
a vortex tube that defines a body having an inlet port connectable to a compressor to receive compressed fluid. The vortex tube is configured to separate the flow of the compressed fluid into a cold stream and a hot stream.
Implementation Method 2
a fluidic oscillator in fluid communication with the vortex tube, wherein the fluidic oscillator defines a first end, a second end, and at least two outlet passages. The first end of the fluidic oscillator is connected to a cold stream outlet port of the vortex tube to receive the cold stream. The fluidic oscillator is configured to generate at least two oscillator jets of the cold stream, operating at different oscillation frequencies, to produce biaxial pulsating flow oscillations
Data Source
AI summary
A cooling system for a gas turbine is disclosed comprising a vortex tube defining a body having an inlet port connectable to a compressor to receive compressed fluid. The vortex tube is configured to separate flow of the compressed fluid into a cold stream and a hot stream. The cooling system further includes a fluidic oscillator in fluid communication with the vortex tube, the first end of which is connected to a cold stream outlet port of the vortex tube to receive the cold stream. The fluidic oscillator is configured to generate at least two oscillator jets of the cold stream, operating at different oscillation frequencies, to produce biaxial pulsating flow oscillations onto a surface of at least one gas turbine blade of the gas turbine. A more efficient cooling system will result from the proposed cooling system's increased cooling impinging surface area and significantly reduced cooling fluid temperature differential.