Pump Flow Guide for Gas Turbine Purge Air
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Solution Overview
Problem
The existing interface between a gas turbine rotor and a transition duct presents a tortuous flow path for purge air, necessitating excessive amounts of air to resist hot gas ingestion into the inner cavity, leading to reduced component efficiency, higher fuel consumption, and potential turbine part life reduction.
Innovation Solution
A pump/flow guide is attached to the transition duct, providing a smooth flow path and centrifugal pumping action to direct purge air radially outward, reducing the amount of air needed to counteract hot gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a traditional interface between turbine rotor and transition duct is used, then the structure is simple, but the flow path is tortuous requiring excessive purge air
Solution Approach 1:
The interface structure is segmented into multiple functional components: a transition duct with inwardly directed purge air slots, a turbine rotor with outwardly directed purge air slots, and a purge air pump. This segmentation allows each component to contribute to creating a smooth flow path that reduces purge air requirements while maintaining structural feasibility.
Solution Approach 2:
The purge air pump acts as an intermediary device that actively manages the purge air flow between the transition duct and turbine rotor. By positioning the pump at the interface and using it to direct purge air through smoothly contoured paths, the system mediates the flow between components to eliminate tortuous paths and reduce the quantity of purge air needed.
2Reliability
If large amounts of purge air are used to resist hot gas flow, then hot gas ingestion is prevented, but component efficiency decreases and fuel consumption increases
Solution Approach 1:
The system changes the parameters of purge air delivery by using a pump to control pressure, flow direction, and distribution. The pump modifies the purge air parameters to create effective sealing at the interface with minimal air quantity, thereby preventing hot gas ingestion while reducing the energy penalty associated with moving large volumes of air.
Solution Approach 2:
The passive mechanical reliance on large volume purge air flow is replaced with an active pumped flow system. The purge air pump provides controlled mechanical energy to drive the purge air through optimized flow paths, substituting the need for high-volume natural flow with a more efficient controlled delivery system.
3Object-affected harmful factors
If additional purge air is utilized without being captured, then hot gas flow is resisted, but combustion exit temperatures increase and turbine part life reduces
Solution Approach 1:
The excess purge air that would otherwise go uncaptured and contribute to elevated combustion exit temperatures is extracted and redirected by the pump system. The pump captures the purge air and directs it through controlled paths where it can effectively resist hot gas flow without being lost to the combustion exit, thereby preventing temperature increases and protecting turbine part life.
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 solution enhances purge air flow efficiency, reducing fuel consumption and extending turbine part life by minimizing the amount of purge air required while maintaining effective resistance to hot gas ingestion.
Implementation Method 1
the structure of the pump/flow guide assists in providing a centrifugal pumping structure that drives the purge air radially outwardly
Data Source
AI summary
A pump/flow guide is positioned in a gas turbine engine and attached to a transition duct to face a turbine disk. The pump/flow guide provides a smooth path for guiding purge flow to resist the ingestion of hot gas. One leg of the pump/flow guide extends radially outwardly and contacts the radially inner section of the transition duct that forms a “fish mouth.” Spaced tabs on the pump/flow guide receive bolts to secure the pump/flow guide to the transition duct. The pump/flow guide thus provides a relatively smooth flow passage for purge gas flow.