Turbulated Aft-End Combustor Liner Cooling
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Solution Overview
Problem
Conventional gas turbine combustors face challenges in achieving uniform cooling and reducing NOx emissions in the transition region between the combustion and discharge sections, as they are prone to high temperatures and limited by the thermal capabilities of existing components, leading to inefficiencies in heat transfer and increased pressure losses.
Innovation Solution
The implementation of an annular cooling system with transverse turbulators on the combustor liner, which enhances heat transfer efficiency while reducing the amount of cooling air required, and incorporates a modified Hula seal configuration to minimize heat transfer to temperature-limited components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If film-cooling is used to protect the combustor liner, then liner integrity is maintained, but cooling air consumption increases and cooling uniformity deteriorates
Solution Approach 1:
The combustor liner incorporates porous material structure that allows cooling air to be distributed uniformly through the liner walls via capillary action and pressure gradients, achieving effective cooling without requiring large volumes of cooling air. The porous structure enables intimate contact between cooling air and the liner inner surface, improving cooling efficiency while reducing air consumption.
Solution Approach 2:
The invention introduces a plenum chamber connected to cooling air sources, using pneumatic pressure distribution to deliver cooling air uniformly across the liner surface. The plenum system regulates and distributes cooling air pressure, ensuring consistent cooling effectiveness throughout the combustor liner while optimizing air consumption.
2Object-generated harmful factors
If lean premixed combustion is used to reduce NOx emissions, then flame temperature decreases and NOx emissions are reduced, but the flame temperature remains too high for conventional combustor components
Solution Approach 1:
The porous combustor liner acts as an intermediary thermal barrier between the high-temperature lean premixed flame and the combustor components. The porous structure provides extensive surface area for heat transfer, effectively dissipating flame heat to the cooling air while protecting the liner and downstream components from excessive temperatures.
Solution Approach 2:
The porous liner material provides thermal management by allowing cooling air to flow through its structure, absorbing heat from the flame side while maintaining structural integrity. This enables the system to withstand lean premixed combustion temperatures that would otherwise damage conventional combustor components.
3Use of energy by moving object
If turbulators are added to enhance heat transfer, then heat transfer efficiency improves, but pressure loss increases
Solution Approach 1:
The porous liner structure provides distributed heat transfer surfaces throughout the liner walls, enabling efficient heat extraction from the combustion gases without requiring discrete turbulator elements that would create pressure losses. The porous structure's extensive internal surface area facilitates heat transfer while maintaining smooth external flow paths.
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 solution achieves improved heat transfer with reduced cooling air usage, lower temperatures in critical areas, and decreased manufacturing complexity, effectively addressing the limitations of conventional cooling methods and maintaining component integrity under high firing temperatures.
Implementation Method 1
transverse turbulators spaced apart axially along the combustor liner and extending radially outward therefrom. The turbulated cooling air enhances heat transfer
Implementation Method 2
the air from the plenum passes through louvers in the combustor liner and then passes as a film over the inner surface of the liner, thereby maintaining combustor liner integrity
Implementation Method 3
incorporates a modified Hula seal configuration to minimize heat transfer to temperature-limited components
Data Source
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AI summary
A turbine includes a transition portion where a combustor section joins a transition piece. The combustor section includes a combustor liner (18) having an aft end (150) that joins a transition piece body (14) of the transition piece. A reduced thickness portion at the aft end of the combustor liner is covered by a cover sleeve (140) to form an air flow passage (42) on the aft end of the combustor liner. Apertures (146) in the forward portion of the cover sleeve allow cooling air to flow into air flow passage. A plurality of turbulators (142) project radially outward from the reduced thickness portion of the combustor sleeve towards said cover sleeve. An arch shaped resilient seal structure (38) is positioned between the cover sleeve (140) and the transition piece body (14). Supports (144) formed on the reduced thickness portion of the combustor liner (18) bear against the inside of the cover sleeve to prevent the cover sleeve (140) from deforming inward due to a force applied by the seal, thereby ensuring that the air flow passage (42) remains open.