Turbine Wheel Space Cooling via Swirl Flow Mixing
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Solution Overview
Problem
Turbine wheel spaces in gas turbines often experience excessive heating due to conduction and windage, leading to elevated temperatures that can reduce turbine output, and existing cooling systems face challenges in delivering cooling flows optimally within the compact and structured machinery.
Innovation Solution
A purge flow delivery system with mixing chambers and baffle plates that redirect and mix cooling flows to prevent direct impingement, reducing pressure losses and enhancing mixing, thereby improving cooling efficiency and flow distribution to wheel spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling flow is delivered to wheel spaces using conventional purge systems, then wheel space temperatures are reduced, but the cooling flow cannot be delivered in an optimal manner due to size restrictions and turbine machinery structure
Solution Approach 1:
The patent introduces a swirl component to the cooling flow, transforming it from a purely axial flow to a combined axial-swirl flow. This dimensional change in flow pattern allows the cooling air to better follow the curved surfaces of turbine blades and reach wheel spaces more effectively, overcoming the limitations of conventional axial purge systems in compact turbine geometries
2Temperature
If cooling flow is increased to maintain wheel space temperatures, then cooling effectiveness is improved, but pressure losses increase and system efficiency decreases
Solution Approach 1:
The patent replaces the conventional mechanical purge system with a fluid dynamic solution that uses swirl generation through strategically positioned holes. This substitution creates a more efficient flow pattern that reduces mechanical pressure losses while maintaining cooling effectiveness, as the swirl component naturally guides the cooling flow along blade surfaces without requiring high pressure differentials
3Temperature
If turbine output is reduced to prevent excessive wheel space temperatures, then wheel space temperatures are controlled, but turbine power output decreases
Solution Approach 1:
The patent introduces a swirl component as an intermediary mechanism between the cooling flow source and the wheel spaces. This swirl flow acts as a mediator that efficiently transports cooling air to critical areas, enhancing heat transfer coefficients and cooling effectiveness, thereby allowing the turbine to maintain higher output while still controlling wheel space temperatures
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 effectively cools turbine wheel spaces by reducing flow losses and increasing mixing efficiency, allowing for higher operating temperatures and power output while potentially using lower-cost materials and reducing the need for excessive cooling flow, thus enhancing the operational efficiency and part life of the turbine.
Implementation Method 1
The baffle plates may interrupt the individual flows entering the mixing chambers, thereby reducing flow losses in the system, and may redirect the fluids so as to generate a favorable swirl of the fluids, resulting in increased mixing in the mixing chamber
Implementation Method 2
The wheel spaces may be located radially inward of a mainstream flow of gas through adjacent turbine stages. Typically, the radially inward discs are heated by various effects, including conduction through the rotor blades, ingress of mainstream flow into the wheel space cavities, and windage heating within the wheel spaces
Data Source
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AI summary
The present application provides a purge flow delivery system that is used with a gas turbine engine (10). The purge flow delivery system includes a mixing chamber (130) with a first sidewall (140), a second sidewall (150), and a cover plate (160), a first inlet tube (180) positioned about the first sidewall (140), the first inlet tube (180) configured to deliver a first fluid (184) to the mixing chamber (13)0, a second inlet tube (190) positioned about the second sidewall (15)0, the second inlet tube (190) configured to deliver a second fluid (194) to the mixing chamber (130), and a baffle plate (170) attached to the cover plate (16)0 and positioned to direct the first fluid (184) at a first angle and the second fluid (194) at a second angle.